DedicAted to the centenary of the Luginin's tHerttGcHanlcal tabor-atom oP Moscow St*ta UnfverHtg International Synpaslun an Calortnetra and Ctieniual ThornadyiMitii»
June 33-38, 1991, noseow, USSR ABSTRACTS Dedicated to tke centenary ef the Luginiii's tHernoohanlcftl l«bar*tor* of ПОБВОИ Stata *nlvar»tt«i International SyMpasiuM MI C*lorinetra. «ml Cbaninal ИмгатАцмиИав
June 83 - 3Bf 1991t Некоей• USSR ABSTRACTS Печатаетоя по решение оргкомитета международного симпо зиума по термохимии и термодинамике
Оформление литературно-иэдатехьокое агенто!о Pi Злинина 1
CHEMICAL THERMODYNAMICS IN THE FUTURE DEVELOPMENT OF CHEMISTRY
INCLUDING ENVIRONMENTAL PROBLEMS
Leo Brewer Department of Chemistry, University of California, and Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.
High-temperature science will be facing unusual challenges in the decade ahead. New technological advances are requiring new materials with unusual properties that will either be prepared by high-temperature techniques or will need to have long-term stability at high temperatures in various environments. One of the major driving forces for new materials arises from the increasing public concern about environmental pollution. Equipment using volatile fluids that can survive up to the stratosphere and destroy the ozone will have to be replaced. Processes that emit sulfur oxides win have to be modified to reduce sulfur emission to very low values. The efficiency of solar energy devices wilt have to be improved and nuclear power plants win have to be designed to make serious accidents extremely unlikely so that energy production by combustion to carbon dioxide is greatly reduced. Many other examples can be given of the need for new materials. The possible combinations of the elements are enormous. The problems cannot be solved by trial and error procedures. Practical predictive models must be developed to narrow down the range of materials that might have the desired products. Examples of possible models win be discussed. 4 THERMODYNAMIC STUDY OF ICE AND CLATHRATE HYDRATES
H. Suga Department of Chemistry and Microcalorimetry Research Center, Faculty of Science, Osaka University, Toyonaka, Osaka 560, Japan
Discovery of glassy crystals leads us to recognize that the glass transition is not the characteristic property of liquids but just one example of freezing-in processes of disordered systems which must occur widely in condensed systems including crystals. Ice provides a good example of disordered crystal. Water molecule in the lattice can have six orientations under constraint of the ice conditions. The heat capacity anomaly observed around 100 К in pure ice was explained in terms of freezing out of reorientational motion of water molecules in the lattice before the crystal reaches a hypothetical transition temperature. Following the suggestion of Onsager, we have tried to do heat capacity measurements on ice specimens doped with various kinds of impurity which might hopeful3.y accelerate the reorientational motion of water molecules by relaxing the ice conditions constraining the motion in the lattice. Among others, alkali hydroxides were found to be highly effective in inducing a long-awaited ordering transition. The transition took place at 72 К with latent heat effect. The associated entropy change depended on the amount of dopant. Maximum entropy change 2.3 JK-^mol-^ was obtained for the sample doped with KOH in 1.3xlO~3 mole fraction and annealed for 3 days around 65 К. A neutron diffraction experiment showed that the low temperature phase is orthorhombic with the protons polarized in a ferroelectric way along the c-axis of the original hexagonal lattice. The name ice XI was given to the proton-ordered ice under atmospheric pressure. The same technique was applied to clathrate hydrate crystals which are composed of several types of Archimedes' polyhedra made of water molecules through hydrogen bonding with guest molecules enclathrated in the polyhedral cages. Many literatures show that both the water and guest molecules are in orientationally disordered state. Dynamic disorder of the guest is known in some cases to persist down to tempe ratures as low as 30 K. Tetrahydrofuran (THF) forms type II clathrate
hydrate of the cubic structure with formula THF.17H20. Previous heat capacity measurement did not show any anomalous behavior. Our remea- surement clarified the existence of a glass transition around 85 К in" the pure specimen. This indicates that reorientational motion of the host water molecules freezes out at 85 К in a similar way to that of ice around 100 K. A THF clathrate hydrate specimen doped with KOH in 10~4 mole fraction exhibited a first-order transition at 62 К with the associated entropy change of 40.12 JK-1mol"l. If the magnitude is re duced to 1 mole of water, the corresponding value is close to that of hexagonal ice. Our dielectric study showed that the real part of permittivity became small in magnitude corresponding to e„of the crystal just below 62 K. This means that the quest molecules become ordered concomitant ly with the ordering of the host molecules. The ordering of water molecules will produce a strong electric field at the guest site suf ficiently enough to align the guest molecules. Thus the electrostatic interaction between the host and guffst molecules will play an impor tant role In inducing the ordering transition in the clathrate hyd rates. In this way, we can continue the study of ordering phenomena in the hydrates enclathrating guest molecules with various magnitudes Of dipole moment in order to examine a relation between the polarity of the guest molecule and transition temperature. s
THEP.HOGHEHICAL DATABASE .. PAST AND PRESENT Donald D. Wagman
Measurements of the therBiochemical and thermodynamic proper ties of many substances and chemical reactioris were begun follo wing the establishment of the first two laws of thermodynamics in the middle of the nineteenth century. This soon made it desirable to bring together in one place a sum mary of the current state of knowleadge with respect to these da ta. These summaries , thermodynamic databases* have taken many different forms and cover a number of different properties . Ыв review here same of the most significant ones ( from a thermoche- mical standpoint ), starting with the compilation by Jul is Thorn- sen, which appeared in 1BB2-B6, and extending up to such recent efforts as represented by the DIPPR project of the American Insti tute of Chemical Engineers and by IVTAN, the program .sponsored by the Institute of High Temperatures of Academy of Sciences,U.S.S.R. 6 THERMODYNAMICS OF HIGH-TEMPERATURE SUPERCONDUCTING MATERIALS G.F.Voronin Chemistry Department,Moscow State University, 119899,Moscow,USSR Two thermodynamic aspects of superconductivity have recently attracted great interest. One of them concerns the equilibria al superconducting transition and properties of coexistent phases in magnetic fields. This way leads to many important common relations between macroscopic properties of substances, and allows to check whether in point theoretical model of the superconductivity is correct or not. Another direction does not relate to the special superconducting properties of substances at all. The thermodynamic methods are applied to them as to any other substance for determination of phase composition, for prediction of material stability in different environment to be affected by atmosphere, covers, targets etc. In such a case they have to deal with the usual problems of chemical thermodynamics, but are complicated because of existence of many components and phases in high-temperature superconducting systems. Serious difficulties in experimental investigation of the systems under consideration consist in slow relaxation especially with regard to diffusion of cations in phases and high chemical reacti vity of new superconductors. This lecture deals with results of both theoretical and expe rimental thermodynamic researches of systems with superconducting phases. The thermodynamic data were obtained more or less complete only for the Y-Ba-Cu-0 system in a solid state. At present there is a few fragmentary knowledge for the other systems with high- temperature superconductors. For the YBa2Cu30e+z(0 YBa2Cu306+z(or '123'), Y2Ba4Cu7014+z('247') and YBa2Cu408t'124') were calculated. At this point emphasis is placed on the problem of the thermodynamic stability of. superconductors. For one below in fig. the phase diagram with stability field of '123* solid solution is shown 111. As seen in the fig.,'123' is thermodynamically stable only in the cross-hatched field limited by the bold lines. Al tempe rature and composition outside this field, the '123' decomposes into other phases according to the reactions mentioned in fig. caption. But when the nucleation and growth of phases with cation stolchio- metry other than '123' is kinetically suppressed, '123' phase may exist for any long time as a metastable phase. Similar diagrams were calculated for the other superconductors in this system. They are helpful for synthesis and application of superior superconducting materials. REFERENCES 1) G.F.Voronin, S.A.Degterjpv, Yu.Ya Skolis. Proc. 3rd German-Soviet Bilateral Seminar on High-Temperature Superconductivity. October 8- 12, 1990. Karlsruhe.P.862-569. 7 z in УВа2СизОб+г Fig. Stability field of the «123' phase. Thin solid lines represent temperature dependence of equilibrium composition at fixed oxygen pressure. Short dashed lines represent equilibria of orthorhombic and tetragonal phases, bold solid lines represent decomposition according to reactions: 1 - 9YBa2Cu306+zMY2BaCu05+YBa4Cu308 5+10BaCu202+(5.5+8z>/202, 2 - 6YBa2Cu306+2=Y2BaCu05+3BaCu02+2Y*Ba4Cu^014+z+(4z-3)/202, 3 - 6YBa2Cu306+z=2Y2BaCu05+3Ba2Cu305+y+Y2Ba4Cu7014+z+(5z--3y-3)/202. e METALLIC SOLUTIONS AND CALORIMETRY. Jean Pierre Bros Universite de Provence, Centre de Saint Jerdme, SETT-UACNRS1168, Avenue Escadrille normandie-Niemen, 13397 Marseille cedex 13, France. Thermodynamic measurements, on the one hand, structural determinations, on the other hand, are essential for the comprehension and the prediction of the properties of liquid and solid metallic solutions. In order to enable a complete thermodynamic description of alloys, equilibrium methods ( for the determination of partial Gibbs free energy) and calorimetric methods (for the determination of integral and partial enthalpies of mixing) are of great and equal importance. In the first part of this presentation, the main high temperature calorimetric methods, used in metallurgy during these last years, are described and discussed. Special attention is paid for experiments performed in severe experimental conditions (high vapor presure of components, high oxidability,...) In the second part, the object is to show, using some examples ( palladium based alloys, ll-VI alloys,...), the particular information deduced from precise calorimetric measurements. In the next future, we believe that efforts should be concentrated on the complete automation of measurements, still more accurate, and taking into account all alloy- environment. THE SOLUBILITY PROCESS OF LEAD(II) ALKANOATES IM THEIR ALKANOIC ACIDS: BINARY PHASE DIAGRAMS. J.A.R.Cheda, F. Ortega, A. Sanchez Arenas and A. Cosio. Dpto. Quimica Fisica, Fac. cc. Quimicaa, univeraidad Complutense. 28040 Madrid. Spain. It is well Known (1-5) the association of alkali alkanoates ("soaps") and alkanoic acids into a crystalline molecular complexes ( called "acid soaps") of a given stoichiometry ( 1:1, 2:1, 3:2, etc. ), which generally melt incongruently. Besides these peritectic points, a lyotropic mesomorphism is frecuently found too. The thallium (I) alkanoates and some acid-salt phase diagrams have been investigated recently (6), showing formation of only an 1:1 molecular complex,.which melts incongruently, and the appearance of lyotropism as well. On changing thallium (I) by lead (II), the binary phase diagram shows a completly different features: 1) No molecular association between the acid and the salt ie found in the solid state. 2) The eutectic point appears at an abnormally low salt mole fraction and exists as an invariant throughout the whole range of composition. 3) The complete phase diagram resembles those of the surfactans in water. A Krafft-like point is found, in which the solubility of the salt increases dramatically. This behaviour may indicate the presence of mieellar-like aggregates in the liquid. 4) At a mole fraction of about 33 molar per cent of the salt, corresponding to the equimolecular amount of hydrocarbon chains, a change in the slope of solubility occurs, pointing to a diferent kind of aggregates in the liquid state. 5) When the pure salt presents thermotropic mesomorphism, lyotropism is also found in this part of the phase diagram. The main techniques used were diferential scanning calorimetry, to determine the temperature and enthalpy of transition, and polarizing light microscopy, to identify the meeophases. The presence of aggregates in the liquid state is cvrrently under investigation using electrical conductivity, viscosity, FTIR, and Raman spectroscopy. REFERENCES: 1. McBain, J.W.; Stewart, A.; J. Chem. Soc. 1933, 924. 2. Brouwer, H.W.; Spier, H.L.; Thermal Analysis; Procedings of the Third IСТА. Davos. 1971, 3, 131. 3. Meisel, T;Seybold, K.;Roth, J.; Melykuti, Cs.; J. Therm. Anal. 1976, 10, 419. 4. Kung, H.C.; Goddard, E.D.; J. Colloid Interface Sci. 1969, 29, 242. 5. Goddard, E.D.f Goldwasser, S.; Golikeri, G.; Kung, H,C.; Adv. Chem. Ser. 1968, 67. 6.. Garcia-Martin, M; Cheda, J.A.R. and Fernandez-Martin, F.; J. Chem. Therm, (in press) and all the references therein. то NEW DEVELOPMENTS IN HIGH TEMPERATURE, HIGH PRESSURE SOLUTION CALORIMETRY TO INVESTIGATE THE THERMODYNAMIC PROPERTIES OF PURE LIQUIDS AND MIXTURES J-P.E. Groller Laboratolre de Thermodynamique et Cinetlque Chimlque. Universite Blaise Pascal, F-63177 AUB1ERE, France. Key thermodynamic data such as heat capacities, thermal expansivities, compressibilities and excess enthalpies are currently obtained Гог pure liquids and mixtures at high temperatures and elevated pressures. These quantities are obtained by direct experimental measurements thanks to new developments in solution calorimetry. These developments are based on the use of Calvet type C-80 Setaram calorimeters, for which we have adapted special cells depending on the quantity to be determined. Heat capacities are obtained in the static mode while excess enthalpies are measured under flow conditions, both in the range 298-570 K, up to 30 MPa. Thermal expansivities and compressibilities are obtained in the same temperature range up to SOO MPa. In the latter case the technique used is a true pressure scanning calorimetry technique with several interesting features, which allows to investigate also pressure effects on solid liquid equilibria. Complementary information is also obtained by means of vibrating-tube densitometry in the range 298-670 К up to 40 MPa. In essence accumulation of the above quantities permits to obtain accurately the thermophysical properties of a dense fluid (pure or mixed) over a PVT- surface. IT AC MICROCALORIMETRY Ichiro Hatta Department of Applied Physics, School of Engineering, Nagoya University, Nagoya 464-01, Japan. When periodic temperature waves with an angular frequency of Ta = Tnexp[~kx+i(wt-kx|], (1 ) . к = ( Ta„ = (Q/ftiC)exp(iwt+iff/2)f (3) where Q is ac heat energy flux per unit area applied to the sample and С is heat capacity per unit area of the sample. When 0 is kept constant during the measurement, the relative change of the heat capacity is obtained. Furthermore, when Q is known, the heat capacity is determined from the measurement of the ac temperature. The latter way is usefully applied to the precise heat capacity measurement of a small quantity of liquid. For this purpose a small metal tube is used as.a sample cell, to which a fine thermocouple is attached for measuring the ac temperature of the * cell. The ac heat energy fl«x is supplied on the semicyUnder of the tube by chopped light irradiation. This arrangement satisfies the condition of ac heat capacity measurement. First, the ac temperature of the vacant cell is measured. Second, the cell is filled by a standard substance, for instance, water, in which the heat capacity is known, and the ьс temperature of the total system is measured. Third, for the cell filled with a substance in which the heat capacity is unknown, the ac temperature is observed. From these three ac .temperatures the heat capacity per unit volume of an unknown liquid sample is determined. In our measurement, the sample cell is made of a very fine stainless steel tube, 130um in inside diameter, 170um in outside diameter and 39 mm long, which is filled with 0.52U1 of a liquid sample. The heat capacity is determined within an accuracy of 1%[1J. When ac light irradiation is applied to the surface of a bulk sample, the surface temperature is shown by eg. (1) in which T. is put as TQ = 0ехр(11г/4)/<шс(ш)1С(ш))*, (4) where c(u>) is the heat capacity of the bulk sample per unit volume at to and Mo1) ib the thermal conductivity of the bulk sample at u. Therefore, this method is highly promising in obtaining the frequency dependence of the heat capacity(2). REFERENCES 1. H. Yao and I. Hatta, Jpn. J. Appl. Phys. 27 (1988) L121. 2. N. 0. Birge, Phys. Rev. В 34 (1986J 1631. 12 Phase Diagrams JLn the Си О based Superconductors Jaroslav SESTAK Institute of Physics of the Czech Academy of Sciences, Na slovance 2, 18040 Prague 8, Czechoslovakia Thermochemistry of HTSC phase formation and phase compati bilities are discussed in view of kinetic phase diagrams [1,2]. Known binary phase diagrams are reviewed and Jointly redrawn for the basic Y-Ba-Cu-0 [3,4] and Bl-Ca-Sr-Cu-0 [5,6] systems. The pseudobinary cuts between YCuO, с, ва_ Cu02« УВагСизОх and Y2BaCuC>4 as well as BiySrCaCU3-y (1 position effect on the CuOx baged HTSC- Thermo. chim.Acta, in print (1991) [5] R.S.Roth et al:"Phase equilibria and crystal chemistry of the SrO-CaO-Bi203_Cu0x system. j Res Nat Ingt Stand. Tech. 95(1991)291 [6] J.Sestak:"Phase diagrams, melt solidification and cry stallization in the Bi-Ca-Sr-Cu-0 system" J.Ther mal.Anal., in print (1991) [7] J.Sestak chapter in the book High Temperature Supercon ductors (V.Narlicar.ed)"Oxide melt fast solidification as a route to prepare HTSC", Nova Publ. New York (1991) (8] J.Sestak, Z.Strnad in Proc. XV Congress on Glass (O.Ma- zurin.ed) "Glass-formation and Y-Ba-Cu-0 HTSC glass-ce ramics" Vol.2, p.112, izd. NAWKA, Lenigrad 1989. THE INTERPLAY BETWEEN SOLUTE SOLVATION AND SOLUTE-SOLUTE INTERACTIONS. Т. Н. Lilley Biolhermodvnamics Laboratory. Chemistry Department, The University, Sheffield S3'7HF, United Kingdom. For some years now we have been studying the thermodynamic properties of amino acids, peptides., and derivatives of these, mainly in aqueous solutions, but . also in other solvent systems.1 Most of the work we have done has been directed towards obtaining information on the interactions which occur between solvated molecules and relating these to molecular structure. However, we have also pursued some studies, in which attention has been given to thermodynamic expressions of the solvation of isolated molecules.2 In much of our work on solute-solute interactions we have directed our attention to the excess properties of solutions and used a Group Additivity approach3 to rationalise the information obtained. Excess properties are defined relative to the infinitely dilute standard state for the solutes ("concentrations" of these are expressed using the molal scale), and to the pure solvent. These properties are then written as a polynomial in solute molality and, for example, the excess enthalpy (per kg of solvent) for a single solute (A) solution, is given by n=«o tf« = tf-tfWeal = ^Гл„Атд (1) n=2 where ЛпД is the enthalpic coefficient for the homotactic interaction of n solute species. The Group Additivity expression for the heterotactic pairwise interaction of solutes is ••AB = \ > tfjjnj"ij" i nnj j (2) where H± j is the term for the interaction of an i group with a j group, and e.g. n, denotes the number of i groups on the solute A. Table 1 gives some values of group enthalpic interaction coefficients and it is clear from this that the secor dary amide group (CONH) iteracts with itself less well than the tertiary amide group (CON) self- interacts. In other words, removal of hydrogen-bonding capacity increases the interaction. An analogous feature is seen for the interaction of amide groups with urea.4 If one considers the hydration of solutes then the enthalpy of hydration (AS0)nHm)i.e. the molar enthalpy change for the transfer of a solute, infinitely dilute in the gas phase, to an infinitely dilute aqueous solution, can also be written in 1) For a summary of much of this work see: Т. Н. Lilley, in Biochemical Thermodynamics, ed. M. N. Jones, Elsevier (Amsterdam). (1988), chapter 1. 2) T. E. Leslie and T. H. Lilley, Biopolymers, 24 (1985) 69a. G. R. Hedwig, J. F. Reading, and Т. Н. Liliey, in preparation. 3) J. Savage and R. H. Wood, J. Solution Chem.. 5 (1976) 733. 4) P. J. Cheek and T. H. Lilley, J. С S. Faraday Trans. 1, 84 (1988) 2545. Ч terms of group contributions and the form of this is given by the following expression8 ABoln*C = ^Asolntfm.i (3) i where the summation is over all chemical groups on the molecule. Table 1. Some group interaction coefficients for aqueous solutions at 25°C. Group i Group j *U J kg moH CONH CONH -292 CON CON -319 CONH urea -296 CON urea -517 Fig. 1 shows the application of this equation to the hydration of amides4-* and it is clear from this that the secondary amide group interacts more exothermically with the solvent than doee the tertiary amide group. The values obtained for Aioln#m are ~53 and -35 kj mol1 respectively. 20 1—1 1 1 1 1 1 0 10 20 30 40 50 60 -(Contribution from side chains) / kJ mol'1 Figure 1. Application of eqn (3) to the enthalpies of hydration of amides,(0) secondary, til tertiary. The indications are, therefore, that the secondary amide group interacts more favourably with water than does the tertiary amide group. The implication of this is that, in consequence, the secondary group will have less tendency to interact with solutes in water than will the tertiary group.' Several other examples • illustrating what seems to be a general unifying principle on the interplay between the solvation of solutes and their propensity for interaction, will be presented. 6) Т. Н. Lilley, Water Science Rev., 5 (1990) 137. 6) G.Barone.G.Castronuovo, G.Della Gatta, V.Elia and АЛаппопь. Fluid Phase Eq. 21 (1985) 1S7. т5 TRENDS AND ANOMALIES IN THE THERMODYNAMICS OF GASEOUS THORIUM AND URANIUM HALIDES D.L. Hildenbrand. K.H.Lau SRI International. Menlo Park, CA 94025, USA The individual bond dissociation energies (BDE) in the gaseous thorium and uranium fluorides, chlorides and bromides ThXn and UXm, where n = 1 to 4 and m = 1 to 5 were derived from high temperature equilibrium measurements. Species were identified and their partial pressures monitored by mass spectrometry over wide temperature ranges. BDE values were then obtained from reaction enthalpies derived from second law analysis. The patterns of BDE as a function of the number of halogen Iigands do not follow regular or predictable trends. For the vranium halides, patterns in the U-Cl and U-Br systems are similar, but differ sharply from those in the U-F system. With the thorium halides, patterns in die Th-F and Th-CI systems are somewhat similar, but those in the Th-Br system show a very different behavior. The results will be discussed. In addition, the sublimation pressures of all the crystalline thorium and uranium letrahalides have been determined by the torsion-effusion method, and the entropies of sublimation have been derived by the second-law method. When compared at the same temperature and pressure, the sublimation entropies of ThF4 and TI1CI4 are 12 to 13 J K"' mol"' lower than their isomorphous counterparts UF4 and UCI4; however, the values for UBr4 and ThBr4 are nearly identical. These comparisons indicate that the entropies of gaseous TI1F4 and ТЬС14 are lower than the corresponding uranium tetrahalides, perhaps because of symmetry considerations. When the total entropies of TS1F4, UF4 and UCI4 were evaluated with an accuracy of ± 2 J K"1 mol"'from the accurate calorimetric entropies of the solids and the sublimation data, it was found that value for ThF4(g) w?s fully compatible witri a regular tetrahedral (Tj) structure, while 1 1 those of UF4 and UCI4 were 14 and 17 J K" mol" larger than values calculated for aTd structure. A less accurate entropy for ThCI4 is again compatible with T PROBLEMS OF SURFACE THERMODYNAMICS A.I. 'Rusanov Chemistry Faculty, Leningrad State University, Leningrad 199034, USSR Still many unsolved problems exist in studying surface tension, the main quantity of the thermodynamics of surfaces. Some of them are related to the establishment of the Htructure and locel properties of surface layers, where the recent progress has been achieved due to computer simulation methods. There 1в a special difficulty in the thermodynamics of solid surfaces. Gibbs first recognized the differen ce between the surface tension and the surface free energy of solids, but the fundamental equation for surface tension was derived only in 1977 /1,2/. It was also found that the above difference originates from the non-uniformity of chemical potential near the surface of a solid. Further progress was related to understanding the anlsotropy of chemical potential /3iV and its application to surface phenomena. /5/. The anisotropy of chemical potential is caused by the stress . anisofcropy, which is related to the problem of determination of sur face stresses and the surface tension of solids. The majority of mo dern experimental methods refer to high temperatures when solids ex hibit plasticity and the principles of measurements are the same as for liquids. Among low temperature methods related to true solids, only one based on the effect of deformation on solubility, gives an absolute value of surface stress. The latber proves to be negative for the boundary of KC1 with its aqueous solution /6/. REFERENCES 1. A.I.Ruoanov, J.Colloid Interface Sci. 1977, §3., 330. 2. A.I.Rusanov, Phasengleichgewichte und Grenzflachenerscheinungen. Akedemie-Verlag, Berlin, 1978. 3. Ja.S.Podstrigach, Soviet Appl. Mechanics a. Techn.Physies, 1965, Nt 2, 67. 4. B.Stuke, Phys.Lett. 1966, 2_1, 649. 5. A.I.Ruoanov, Pure a. Appl. Chem. 1r^59, 61, 194-5. 6. G.V.Berenstein, A.M.Dyachenko, А.Л.Rur.anov, Dokl. AN SSSR, 1988, 298. 14o2. T7 i-LUOKIKli COIiBUoTIOK CALOHIluiTHY. : ГКОСОДой IN LA^T YEAUS AND Y.'AYS OF THb' PUHTHHli rBViilOllKKT V.Ya.Leonidov, P.A.G.O'Hnre Institute for High Temperatures of the USSR Academy of Sci ences, Moscow, USSR ; National Institute of Standards and Techno logy, Gaithersburg, Maryland, U.S.A. Modern state of the fluorine bomb calorimetry (FBC) is dis cussed. The survey of the results obtained by FBC-method after pu blishing firat reviews in this area [1,2] is given.The use of flu orine in calorimetry has provided a direct way of measuring enth alpies of formation of the inorganic fluorides.In last years the data for the higher fluorides of twelve metals and two nonrmetals were obtained.This information (together with the Д..Н -values for fluorides of' other elements determined by the same method former ly) hae created a sufficient base for determining by FBC the en thalpies of formation of different inorganic compounds. Below the classes and number (in brackets) of the compounds are listed which have been investigated by FBC-raethod in last de cade : oxides (1).sulphides (1l),selcnideR (7),tellurides (4),ni trides (7),lower fluorides (2),other compounds (2)).Many of these compounds are rather hard to test by conventional thermochemical methods.Some of substances investigated are very fluorine-resis tant. The combustion of such substances (e.g. dense modifications of ВЫ ) caused particular difficulties.Proper selection of the op timum combustion conditions has ensured a high degree of combus tion of these compounds. Specific problems attending the use of fluorine in calorimetry consist in the necessity to avoid distor- sion of the experimental results due to thermal side effects.Spe cial .precautions have been-taken to eliminate or to minimize the-' se effects in a each case. Some of compounds investigated were va riable-composition compounds (somechalcogenides of metals,uranium compounds et al.). Problems of the investigation by FBC-method of nuch substances and the relationship between "x" and AfH°(ABx) were discuosed in the work [3J . The extermination of the enthalpies of formation of the de nse modifications of BN were carried out for the first time by FBC-method at Institute for High Temperatures (Leonidov et al.). Based on these data a more precise pressure-temperature phase di agram of boron nitride was obtained [4].It has changed essenti ally our ideas concerning polymorphism of BU. The search of new effective fluorizating agents for calori- ffletry is an urgent problem. Group of Soviet investigators at In stitute for High Temperatures has developed apparatus and proce dures permitting measurements in a calorimetric bomb of enthalpi es of fluorination reactions with participation of crystalline xe non difluoride (e«gn see f5]).It is a new variety of PBC-method. This group is going in future to continue the determination of AfH°-values of lower fluorides and some variable-composition co mpounds,mainly borides and silicides of transitional i.ietals, by ?BC-method. Fluorine combustion caloriraetry is useful especially for the investigation of these compounds because one from pro - ducts of theirs fluorination reactions is gaseous substance (bo ron trifluoride or silicon tetrafluoride). For a number years American investigators at Argonr.e Natio nal Laboratory have been using PBC-method to determine the AfH°- values of high-temperature and refractory materials.In the past time these studies have tended to concentrate on chalcogenldes of ть metals and пэп-metalc having many technical applications (elect ronic industry,catalysis,extractive metallurgy,manufacture of high-temperature labricants and so on). These investigations will be continued in future. There is the programme of the determina tion of the enthalpies of formation of some vitreoun chalcogeni- dea worked out recently at liational Institute of standards and Technology (U.S.A.).The FBC-method will be used for this aim. There are the first results in this field now. It is expected that a new data obtained will provide bench-mark information for the study of the amorphous state and for characterization of the in teratomic forces which have been postulated to govern the enthal py changes associated with vitreous-to-crystal transitions. It is proposed to use FBC-method for determination of the AfH-values for the compounds of more than three elements. The first quaternary compounds investigated by this method is S-MAsF- (O'Hare et al.,198y). d b The overall uncertainty of the results obtained by FBC-me thod is often of the order O.Ob * 0.1 per cent.lt compares favo rably with oxygen bomb calorimetry.The fluorine-combustion calo- rimetry technique is uniquely suited to the determination of 4fH° -values of chalcogenides,borides,3ilicides,nitrides,lower fluori des and some other compounda.lt yields results superior to con - ventional experimental thermodynamic methods. The problem of the selection of test substances for fluori ne combustion calorimetry is discussed.Tungsten and sulphur have been suggested as- test substances for such investigations.At pre sent time germanium and boron appear to be the best new candida tes for FBC test substances. REFERENCES 1) V.Ya.Leonidov,V.A.Medvedev. Fluorine Calorimetry. Nauka : Moscow. 1978 . 2) W.N.Hubbard,G.K.Johnson,V.Ya.Leonidov. Experimental Chemical Thermodynamics. 'Vol. 1. Combustion Calorimetry. Chap. 12 . Sunner &. ,]tiansson M. : editors, Pergamon Ргевз! New York, 1979. 3) V.Ya.Leonidov.V.A.Medvedev. 6 th International Conference on Thermodynamics, August 2G-2y,1980 : extended Abstracts of the Main Lectures. Merseburg.GJJli : 19U0, p. 3. 4) V.Ya.Leonidov,I.V.Timofeev. Zh.IIeorg.Khim.,1989,vol. 34, N 10, p. 2701 . 5) V.Ya.Leonldov,I.V.Timofeev,Yu.M.Kiselyov. Dokl. Akad. Nauk SSSH, 1984, vol. 274, H 2, p. 36'j . 6) P.A.G.O'Hare , J.Chem.Thermodynamics, 1987,vol. 19, N 7,p. 675. T9 EXPERIMENTAL TECHNIQUES IN HIGH TEMPERATURE THERMODYNAMICS. K.L. Komarek Institute of Inorganic Chemistry, University of Vienna, A-1090 Vienna, Austria In previous publications the author has quite extensively discussed experimental techniques applied in high temperature thermodynamics and phase diagram studies 1)2)3). Since then other publications have treated the same or similar subjects 4)5)6). Presently an attempt will be made to give an overview of the most recent developments in various selected fields. Since calorimetric methods will be treated elsewhere in more detail special emphaele will be placed on EMF and vapor pressure methods. The essential criteria for the satisfactory application of solid electrolyte galvanic cell techniques will be presented and the principal electrolytes presently In use will be surveyed. Special variations of the cell technique uaed in thermodynamic studies are descsrlbed. As far as the vapor pressure methods are concerned the focus will be on the fundamentals of the Knudsen effusion mass spectrometry with respect to the recent methodic development*. Advancements were less due to radically new techniques but more to automated control, data acquisition and processing. REFERENCES 1) K.L. Komarek, Бег. Bunsenges. Phys. Chem. 87 (1983) 709. 2) H. Ipser, K.L. Komarek, Z. Metallkde 75 (1984) 11. 3) K.L. Komarek, H. Ipser, Pure Appl. Chem. 56 (1984) 1511. 4) H. Brodoweky, H.-J. Schaller (eds.>, "Thermochemistry of Alloys: Recent Developments of Experimental Methods", Kluver Acad. Publ. Netherlands (1989). 5) K. Hilpert, Structure and Bonding 73 (1990) 97, Springer-Verlag, Berlin. 6) J.N. Pratt, Met. Trans. 21A (1990) 1223. 20 ELECTROCHEMICAL BTUDIE8 WITH FLUORIDE ELECTR0LYTE8 C.B. Alcock University of Notre Dame,Center for Sensor Materials, Notre Dame,USA Solid -fluoride electrolytes can be used to measure the stabi lities of metal fluorides in conventional galvanic cells,but,fol- loMing Levitsliii,may also be used to establish the stabilities of metal oxide and inter-oxide compounds .With a dispersed phase in corporated in the electrolytes,oxygen, sulphur and hydrogen sen sors may be constructed which are finding industrial application. MODELS FOR THERMODYNAMIC DATA OF SOLUTION PHASES Rand M. The development of sophisticated software in association with computer'databases containing reliable assessed thermodynamic data has become an increasingly powerful tool for the prediction of the behaviour of a wide range of materials in chemistry , metallurgy and materials sciences.Users can now solve the precise multyphase equilibrium in multycamponent systems in which they are interested - for example phase equilibria in ten component steels or the in teractions of a molten nuclear- core with concrete or bed-rock - instead of relying on published phase diagrams of binary , ternary or occasionally higher order systems. Far these databanks to be useful, the models employed for the thermodynamic data must be general and realistic . The paper will review the models used predominantly, but not exclusively, those for solution phases in the SATE(t) data bank. These models include - Representation af the data' for elsments and pure substances - including measurable states,magnet!с and ordering contributions) - Models for simple substitutional phases such as alloys - Sub-lattice models for complex solids such as spinels - Models for liquid alloys - Models for liquid oxides and molten salts - Ternary and higher-order systems A few typical applications of the use of such databases will be shown. 21 THERMODYNAMIC PROPERTIES OF ALKALI METAL ALKANOATES P.Ferlani and E.F.Westrum* Dipartimento di Chimica Fisica and Cste-Cnr,Universita ,Viale, Taramelli 16,27100 Pavia,Italy * Department of. Chemistry,University of Michigan,Ann Arbor, Mlchi gan,USA Alkali metal alkanoates ,especially those with a low number of carbon atoms in the organic chain .currently find application in various areas of chemistry , as intermediates or catalyst in organic reactions ,as electrolytes in electroanalytical methods and electrochemical processes , as materials for energy storage .detergents,etc. However, their thermal behavior is still poorly understood so far. Therefore, it seems worthy to investigate the thermodynamic properties of alkalyalkanoates with shot carbon chains . Experimental data collected by means of adiabatic calorimetry from low .temperature to the temperature of existence of liquid crystals and isotonic melts ,have allowed to gain a deeper under— standing of the phase transition sequence and of the melting me chanism in this salts. In the present work ,attention will be focused, in particular , on solid-solid transitions and step wise melting phenomena in the series of lithium alkanoates from formate to dodecanaa'te ,and on the thermophysic of the group of the five alkali acetates. 22 Thermodynamic Investigations by Knudsen Effusion Mass Spectrometry and Differential Thermal Analysis for the Development of High Temperature Alloys K. Hilpert Institute for Reactor Materials Nuclear Research Centre (KFA), Julich Federal Republic of Germany Nickel-base alloys for high temperature applications are Strengthened by the intermetallic compound precipitate f of the type AlNi3 in the FCC (V) matrix. A further group of high- temperature structural materials are ordered intermetallic phases. The nickel-aluminides, especially the А1Шз phase, are considered to be important model materials for this research. The nickel-rich part of the Al-Ni phase diagram, xNi •= 0.7 to 1, is of fundamental interest for the aforementioned alloys, since it contains the у matrix, the y' phase of the type AIIU3, and the y/y* two phase field. Therefore, the thermochemistry of the solid phase and the melt as well as the phase diagram have been investigated by us for this concentration range by the use of Knudsen effusion mass spectrometry and high temperature differential thermal analysis. New results on the phase diagram as well as thermodynamic data for the melt and the condensed phase, such as chemical activities and thermodynamic properties for the formation of the y' phase, are reported. The influence of В and Hf additions to the Al-Ni alloys on the data was elucidated. Such additions are important for practical applications. The investigations on the binary and ternary alloys are complemented by the study of y' strengthened multicomponent nickel-base alloys leading for example to the determination of partial pressures and the solvus temperature for the y' phase. 23 CHARACTERISATION AND THERHODYNAHIC PROPERTIES OF Te-RICH PHASES IN Сг-Te SYSTEN I A HIGH TEMPERATURE MASS SPECTROMETRY STUDY R. Viswanathan, M. Sal Babe, D. Darwin Albert Raj, R. Balasubramanian, T. S. Lakshmi Narasimhan and С. К. Mathews Radlochemlstry Programme, Indira Gandhi Centre for Atomic Research, Kalpakkam - 603 102, Tamil Nadu, India. ABSTRACT The Cr-Te binary system has been the subject of several investigations including the most exhaustive study by Komarek and his coworkers [1] who used several, techniques such as d.t.a., X- ray, and isoplestic vapour pressure measurements. However, there are still many questions relating to the Te-rlch regions. The homogeneity range of CrTe», described as a novel polyte1luride, is not delineated unambiguously. Doubts persist as to whether CrTe- exists from 71 to 75 at* Те or whether another polytelluride phase with a narrow homogeneity range lies at 70 at* Те. Moreover, the only thermodynamic data reported for any of the phases in this region are those given by Goncharuk and Lukashenko C2J for CrTe-. These authors determined the activities of chromium by e.m.f. technique and deduced the integral thermodynamic quantities for Cr„Te3 by assuming tellurium activity, to be unity at all compositions above 60 at* Те. The present study was undertaken to resolve some of these anamolies. For this purpose, the high temperature mass spectrometric method was adopted as the principal technique. The samples of Cr-Te alloys of starting compositions 83, 80, 70 and 67 at X Те respectively' were vaporised from Knudsen cells. On account of the fact that tellurium vaporises preferentially, various 1 24 compositions richer In Cr could be realised In situ through the measured remo at of tellurium. The partial pressures of Te-(g) as veil as the compositions corresponding to them were deduced from the lon-lntensities of Te„ measured alt through the vaporisation period. The following Inferences could be drawn from the results. There could exist at least one hitherto unknown polytelluride phase above 75 at* Те. The homogeneity of СгТвэ ranges from 70 to 75 at% Те. A two-phase field exist» between 63.5 and 7C at* Те. The partial pressure of Те, (g) changes only by a factor of three as the sample composition changes from 63 to 63.5 at* Те < from 1.5 to 0.5 Pa at T=650 Ю. Since this corresponds to a change of only 40* in activities, the differences In the thermodynamic stabilities of the various phases would be small. We believe that this might have been the reason why many workers concluded that the region above 60 at% Те consisted of only a two-phase field with elemental tellurium as one of the phases. The integral thermodynamic quantities for the phases Identified in this work were derived by Glbbs-Duhem integration, using our data and a- given by Goncharuk and Lukashenko . REFERENCES 1. H. Ipser, K. Komarek and K.O. Klepp, J. Less-Comm. Met., 92, 265 (1983). 2. L.V. Goncharuk and G.M. Lukashenko, Poroshkovaya Met.. 9, 45 (1974). 25 THE CHARACTERISATION AND THERMODYNAMIC PROPERTIES OP MOLECULAR ALKALI METAL IODATES AND PERIODATES J.S.Ogden, R.A.Gomme, J.T.Graham, K.R.Biggs Dept. of Chemistry, University of Southampton, Southampton, U.K. The vaporisation of alkali metal iodates and periodates has been studied by mass spectrometry and by matrix isolation i.r. spectroscopy. Although, some sample decomposition takes place, ternary molecular epecies have been detected in these experiments, and their vibrational spectra assigned. -. This presentation describes the results obtained, and discusses their interpretation from both structural and thermodynamic aspects. 26 THERMODYNAMIC MIXING FUNCTIONS AND PHASE EQUILIBRIA IN THE CHROMIUM-NICKEL SYSTEM BY HIGH TEMPERATURE KNUDSEN CELL MASS SPECTROMETRY J. Tomiska, K. Kopecky, A. Meckel, and £*. Myers* Institute for Physical Chemistry, University of Vienna, Wahringerstrasee 42, A-1090 Vienna, Austria. Thermodynamic mixing functions of solid chromium-nickel alloys (0.45 * On leave from Department of Chemistry and Institute for Materials Research, State University of New York at Binghamton, Binghamton, NY 13902-6000, USA. 27 THERMOCHEMICAL PBOPERTIKS OF CERTAIN METAL CHLORIDES GASES R.J.M. Rollings and E.H.P. Cordfunke Netherlands Energy Research Foundation ICN, P.O. Box 1, 1755 ZG Petten, The Netherlands Metal chlorides play an Important role in many technological processes such as chemical vapour deposition (CVD) of thin layers of ceramics or semiconductors, nuclear chemistry, or high pressure discharge lamps. The high-temperature reactions осиrring in these processes can be modelled adequately with modern thermochemical computer codes. However, gaps still exist in the basic thermodynamic input data of several inte resting metal chloride systems. In the present paper a review of recent experimental studies by the authors will be given. These include high-temperature infrared spectroscopy as well' as vapour pressure measurements for tungsten hexachloride, uranium tetrachloride and yttrium trichloride. From the - results data for the heat capacity, entropy and enthalpy of formation have bee* derived. Critical evaluations of the available literature for these metal chlo ride systems will be given. гв STANDARD GIBBS ENERGIES OF FORMATION OF СаСгОд AND SrCr04 ВУ CaF--BASED EMF METHOD О M SREEDHARAN, A M AZAD AND R SUDHA METALLURGY DIVISION INDIRA GANDHI CENTRE FOR ATONIC RESEARCH KALPARKAM, TN 603 102, INDIA. * External Research Student ABSTRACT Thermodynamic stabilities of CaCrO. and SrCro4 are of interest to materials scientists and also in nuclear technology as these are the possible compounds of fission product-cladding chemical interaction under conditions of accident in fast nuclear reactors. Though there are some reports on the thermodynamic stabilities of CaCrO. and BaCrO. by fluoride electrolyte emf method, there is no reliable thermodynamic information on SrCrO.. Hence the emf of the following types of galvanic cells were studied under an atmosphere of pure oxygen at a pressure of 1.01x10 Pa, over the ranges 788 to 1070 and 851 to 1116 К where M is Ca and sr respectively: Pt<, 02 (g), CaO„ CaF2 /CaFj /MFj, MCr04, Cr2o3, 02 (g), Pt 1 Prom the cell emf data* the standard Gibbs energy change* «GR* . for the reaction: MO + 0.5 cr2o3 + 0.75 o2 = мсго4 were derived to be as follows: Двд (+ 0.63)/ kJ = -166.4 + 0.08821 T/ К Дв° {+_ 0.29)/ ко = -178.3 + 0.10142 T/ К for Ca and Sr respectively. 29 PREPARATION, CHARACTERIZATION, AND PHASE EQUILIBRIA STUDIES OF THE Cd-Bi-S SYSTEM. L.A. Morales and P.W. Gilles, Department of Chemistry, University of Kansas, Lawrence, Kansas 66045. Bismuth cadmium sulfides have interesting electronic and optical properties. A knowledge of the thermodynamic properties, vaporization reactions and vapor pressures is important in the synthesis and utilization of these materials. The phase CdBi2S4 was synthesized both from the. elements and the binary sulfides. Portions of the CdBi2S4 phase were used in two vaporization studies. The first was the vaporization of CdBi2S4 from a graphite Knudsen cell under high vacuum. The second was the vaporization of CdBi2S4 from a graphite boat under flowing Ar. Twenty residues were collected; each condensate was subjected to wet chemical tests. The CdBi2S4 and the residues were characterized by x-ray powder diffraction. The results indicate that CdBi2S4 vaporizes incongruently to give Bi(l) metal and CdS(s). The identities of the vapor species a-~ unknown. ::o THERMODYNAMICS AND PHASE EQUILIBRIA IN THE ALUMINUM-MANGANESE SYSTEM BY HIGH TEMPERATURE KNUDSEN CELL-MASS SPECTROMETRY R. J. Kematick, d. E*. МУ-£Х£ Department of Chemistry, Institute for Materials Research, State University of New York at Binghamton, P. 0. Box 6000, Binghamton, NY 13902-6000, USA The aluminum-manganese system has been studied by Knudsen oell-maee spectrometry in the temperature range 1100-127SK and composition range 42-62 atomic percent manganese. Thermodynamic activities were obtained by direct comparison with the elements. The variation of manganese activity vith composition at 1175K was found to agree with the published phase diagram. Free energies of phase formation at 1175K were calculated (cal/g-atom)i А10.57Мп0.4з (gamma-2) -3776 Al0.50Mn0.50 (дммпа) -3742 ^O^S^O.SS (epsilon) -3784 SI Thermodynamic Properties of Eulytine Bi4[Si04)3. Yu. V. Semenov, M. Gambino* J.P. Bros*, V.M. Gurevich, M. Gaune-Escard* Vemadsky Institute of Geochemistry and Analytical Chemistry , Academy of Sciences of U.S.S.R., Moscow, Kosygln str. 19,117975 (U.S.S.R.) *SETT, UA1168, Universite de Provence. Centre de St -Jerome, Avenue Escadrille Normandie Niemen, 13397 Marseille cedex 13 (France). The knowledge of the thermodynamics of bismuth silicates is important for constructing the phase diagram of the Biz03-Si02 system. This is of interest in several fields like geology (mineral paragenesis of bismuth deposits) and electronics (elaboration of new materials). Thermodynamic properties cf eulytine were determined for a sample synthesized by hydrothermal method. The chemical analysis of substance was found close to the theoretical formula. The molar mass of eulytine was taken 1112.171 g • moM in all published values. Using a high temperature Calvet-type calorimeter, the enthalpies of solution of eulytine В1гОз and SiOz in the 2РЬО ВгОз melt were measured sA 973 K. The values of the enthalpy function of eulytine so obtained are reported in the following table . Table : Enthalpies of solution of substances in melt 2РЬО В2О3 and enthalpy functions. Compound Д soiW V 973K H ° m,973 -W °m.298.i5 Ref. kJ-moM kJ- moM ВЦНСф 116.7 ±5.3 (8)* 297.3 (299.4± 3.0 (4))" this work B12O3 44.3 ±1.4 (7) 85.06 (1,2) S1O2 -4.22± 0.20 (23) 43.74 (3,4) * : number of runs.; **: experimental value. The heat capacities of this mineral were measured by the adiabatic method from 13 to 310 К and by the d.s.c. method from 310 to 770 K. Heat capacity measurements at low and itigh temperatures are in a good agreement. Using these data and the value H V973 -H °m.298.i5 , the following equation was obtained for the 32 temperature dependence of heat capacity in the temperature range 250-1000K : Cp" = 3Rn (1+949.12/T2-104.7/T) + 0.08196T, where R : gas constant, n : numbers atoms in formula. According to the values in the table , we calculated the enthalpy for the reaction : 2Bi203 +3SiOa = Bi4[Si04J3 Areacl.W°m.973K = 40.8±5.6 kJ.moM and A react.H °т,298.15 К = 44.8 ± 6.1 kJ.mol-1. These experimental data allow standard values of heat capacity, entropy, enthalpy of formation, and Gibbs free energy to be calculated. REFERENCES. 1) Beresovskaya Yu.M., Semenov Yu.V., Vasil'eva I.A., Khodakivskil I.L.; Zhur. Fiz. Khim. 1989. g3.,5,1368-70 (RUG). 2) Pankratz LB.; Thermodynamic properties of elements and oxides. U.S. Bur. Mines, 1982, N672. 3) Lapma I.V., Semenov Yu.V., Khodakovsky I.L; Geokhimia. 1989, 7,1033-36. 4) Gronvold F., Stolen S., Svendsen S.R.; Thermoch. Acta, 1989, 132. 225-43. 23 THERMODYNAMICS OF PD-AL. PD-GA and PD-IN ALLOYS. J. P. Bros, M. Gaune-Escard, E. Hayer*. University de Provence, Centre de Saint-Jer6me, IUSTI-CNRS UA 1168, Avenue de I'escadrille Normandie-Niemen 13331 Marseille cedex 123, France. * University of Vienna Institute of Inorganic Chemistry, Wahringerstr. 45, 1090 Vienna, Austria. For each three systems Pd-AI, Pd-Ga and Pd-ln, the thermodynamic quantities ( enthalpy of formation, Gibbs free energy and equilibrium phase diagram ) were collected and analyzed. The enthalpies of formation of liquid alloys containing gallium and indium were measured experimentally. The apparatus used was a fully automated very high temperature calorimeter ( Tmax. - 1500 °C). These results were compared to the few available experimental data, on the one hand, and to the values calculated from traditional models, on the other hand. cA ENTHALPIES OF FORMATION OF LIQUID NdCla-KCI MIXTURES. M. Gaune-Escard, A. Bogacz*, L Rycerz*. W. Szczepaniak*. IUSTI-SETT, UA 1168, Universiti de Provence, Centre de St Jer6me, Avenue. Escadrille Normandie Niemen, 13397 Marseille Cedex 13 (France). Mnstitut de Chimie Inorganique et de Metallurgie des Elements Rares, Ecole Polvtechnique.Wybrzeze St. Wyspianskiego 27, 50370 Wroclaw (Pologne). Thermodynamics of NdCta-based melts is important for the electrolytic elaboration of the neodymium metal. Following our preliminary calorimetric investigation of NdCl3 and of of the definite compounds CseNdCle <1) . the present work deals with the enthalpies of formation of liquid KCI-NdCb melts. The phase diagram of the KCI-NdCfc system (2) exhibits the following features : • The components KCI and NdCta melt at similar temperatures (1045 К and 1032 K, respectively. • The KsNdCle definite compound melts congruently at 955 К , after a solid transition at 618 K. • The K2NdC!s uncongruently-melting compound decomposes at 863 K. • Two eutectic mixtures are formed (XKCI = 0.5 and Tm = 753 К ; XKCI = 0.82 and Tm = 888 K, respectively). Calorimetric mixing experiments were conducted at 1065 K, e.g. at a temperature corresponding to homogeneous liquid mixtures. The apparatus used was a Calvet-type high temperature microcalorimeter and mixing of the two liquid components was obtained with the break-off ampoule technique (3)- The enthalpy variation corresponding to the reaction : (1 - x) NdCb (I) + x KCI (I) -> ((1 - x) NdCI3, x KCI ] (I) was measured on the whole composition range. It is strongly exothermic with a minimum at about 18 kJ/mol deported towards KCI-rich compositions. The enthalpies of fusion of NdCte and of thefoNdCte definit e compound were also determined by differential enthalpic analysis. REFERENCES 1) M. Gaune-Escard and A. Bogacz, International Conference On High Temperature Chemistry of Inorganic Materials Conference, 3-7 April 1989, Gaithersburg, Maryland, USA. 2) In-Chzhu Sun and I. S. Morozov, Zhur. Neorg. Khim., 3 (1958) 1946. 3) M. Gaune-Escard, "Calorimetric methods" in" Molten Salt Techniques", D. G. Lovering and R. J. Gale, editors. Plenum Press, New York, London (1991). Effusion Chemistry in the GaTe-Ga System Fannee Makdeeprom-Burckel Jimmie G. Edwards Depaftment of Chemistry University of Toledo Toledo, OH 43606 Phone:(419)537-2111 Fax: (419) 537-4033 Gallium teUuride is an important example in understanding the high temperature chemistry of III—VI phases. It is used in optical recording devices and a variety of thin-film ternary phase applications. In the present work, die vaporization chemistry and vapor pressure of Ga-Te samples with initial mole fraction of Те of 0.503 ± 0.002 and 0.436 ± 0.003 were studied in the temperature range 921-1102 К by the simultaneous Knudsen effusion and Volmer (torsion) effusion method. Conformity with published phase diagrams of Ga-Te was found, and a new phase, GaTen^(s), was discovered. Chemical analyses of starting materials and residues showed the vaporization of GaTe(s) and GaTeQ>96(s) to be incongruent, but that of die latter is very close to being congruent. Vaporization reactions and their ДН°(298 К) were established in five composition and temperature ranges. On die basis that ДЕГ(298 К) of GaTe(s) and 1/2 Te2(g) are -78.8 ± 2.4 and 84.2 ± 0.4, kJ/mol of Те, respectively, then the ДН°(298 К) of GaTe„ 96(s), liquid LI (X,.,. = 0.30), and liquid L2 (X^ = 0.10) are -79 ± 3, -66 ± 22, and -48 ± 6 kJ/mol of Те, respectively. Comparisons with published calorimetric data and implications for solution models will be presented. 36 TESTING THE VOLUME PRIORITY AND THE PHONON DISTRIBUTION METHODS FOR THE ACCURATE RESOLUTION OF HEAT CAPACITY Edgar F. Westrum, Jr., Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109 U.S.A. in order to resolve transitions and thermophysical contributions to the heat capacity extending over relatively large ranges of temperature, we have developed two rather specialized methods for the evaluation of the (vibrational) lattice heat capacity valid to a high degree of accuracy compared to the typical extant procedures. The earlier developed method is designated the "Volume Priority Method", and it takes in account the relative predominance of volume (rather than mass) over the "chemical thermodynamic region" below 300 K. It has been employed in recent years in the resolution of Scnottky contributions arising from the splitting of the ground state by the crystalline electric fields of lanthanide salts with excellent results. The newer method is the "Komada/Westrum Phonon Distribution" method and although it has a generic resemblance to the well-known Debye approach it succeeds where Debye fails. It has been used for the resolution of magnetic and other transitions in the such mineral systems as deerite and grunerite.and enables the resolution of minute electron derealization phenomena. A major te^t has been recently completed on the 13 members of the lanthanide (Ln) sesquisulfides (Ln2S3) plus (Y2S3) in the resolution of the Schottky levels. Despite the very significant differences in the presuppositions and theoretical backgrounds of the two methods. The agreement between the two approaches is indeed impressive and well within the experimental error of determining such frequencies by either calorimetric and/or spectroscopic measurements. The heat-capacity maximum near 3 К reported reported ln Tb2S3 and interpreted generally as a low-energy electronic phenomenon must actually be interpreted as of magnetic origin. If the eight levels of the ground state are used, an excellent fit is obtained. But if one level is used to fit the 3 К maximum the remaining portion of the spectroscopically derived heat-capacity contribution accounts for only approximately one half of the excess that is obtained by calorimetry. This is an example of the strength of the calorimetric approach. Finally the concepts will be contrasted with some recent developments by Grimval bearing on the Latimer ("mass priority") approach of the mid-20th century. 37 THERMODYNAMIC STUDIES USING ULTRA-HIGH TEMPERATURE MASS SPECTROMETRY John W. Hastie High Temperature Materials Chemistry Group, National Institute of Standards and Technology, Gaithersburg, MD 20899 USA Conventional effusion cell and molecular beam'probe techniques are limited in both the temperature and pressure regimes of applicability. Reaction between sample and cell or probe generally limits the upper temperature attainable to about 2C00 °C. Recent work in our laboratory [1,2,3], and elsewhere, has shown the utility of laser heating as a means of avoiding the containment problem at higher temperatures. By focussing a high power pulsed laser beam on only a small area of a specimen, the surrounding material remains.relatively cool and serves as an inert container. The gas dynamics associated with the plume formation and beam generation process appear to yield a representative sample with a well-defined temperature, which is analyzed using molecular beam mass spectrometry. Beam velocity analysis, time-resolved beam evolution profilec, and neutral species distributions all support the conclusion that local equilibrium can obtain in refractory materials under laser vaporization conditions. Thus, in principle, thermodynamic data can be obtained, as will be shown for the refractory materials BN, C, SiC, Th02, and MgO, at temperatures to 5000 К and at pressures in the region of 0.1 MPo (1 atmosphere). REFERENCES 1) J.W. Hastie, D.W. Bonnell, and P.K. Schenck. High Temp. Sci, 25, 117 (1988). 21 J.W. Hastie, D.W. Bonnell, and P.K. Schenck, High Temp.- High Press. 20, 251 (1988) 3) D.W. Bonnell, P.K. Schenck, J.W. Hastie, and M. Joseph, in Proceeding of the Symposium on High Temperature Chemistry, "Ultra-High Temperature Laser Vaporization Mass Spectrometry of SiC and Hf02," (Materials Research Society Fall meeting, 1990). L-6 THERMODYNAMIC SIMULATION (IDS» OF DEPOSITION OK YBa2Cu30y(123-Oy) FROM A GAS-VAPOR PHASE N.I.Ilyinych.G.K.Moiseev.N.A.Vatolin Institute of Metallurgy.Ural Department of the USSR Academy of Sciences.Sverdlovsk The conditions for processing of films of 123-0y by depositions from a gas-vapor phase have been investigated by TDS111. The investigation was conducted in three stages. At first it was attempted to reproduce the results [2] by help of АСТРА program [31. Among the compounds of Y-Ba-Cu-O system it was taken into account only 123-Oy at y=7 as well as in (2). It appeared that 123-Oy had been deposited at 550-1050 К together with other phases(Y2O3,BaC12,Ba(0H)2), the yield of 123-Oy being much less than the yield of the other phases. Attempts of increase in the yield by variation of parameters and ratio of precursors were not successful and we failed to reproduce the results [21. It may be due to: - different sources of thermodynamic properties of substance.in particular, difference in H for Culfg) in comparison with data (4(; - the lack of lucidity of the composition of 123-Oy in 121. At the second stage as the precursors were used compounds different from ones in [21. Among the components of Y-Ba-Cu-O .system only 123-Oy was taken into account. It appeared that 123-07 had been formed at 400-1400 K, its yield being nearly equal to 1. At the third stage it was simulated almost real system including in addition to 123-Oy a number of compounds of Y-Ba-Cu-O system whose properties were calculated by us. The conditions of deposition of 123-06 at 800-1400 К were determined.The formation of 123-07 was not discovered. The experimental verification of the computed results was begun. REFERENCES 1) G.K.Moiseev.N.A.Vatolin.Rasplavy,4(1990).18. 2) M.Ottosson et al.Cryst.Growth.96(1989).1019. 3) G.B.Sinyarev i dr.Primenenie EVM dlya Termodinamicheskikh Raschetov Metallurgicheskikh Protsessov.-M.Nauka.1982. 4) I.Barin.O.Knacke. Thermodynamical Properties of Inorganic Substances.-Bar1in:S.V.-1973. '••О HtERGETICS СЕР MIUNO OF SOKE FERROMAGNETIC SOLID SOLUTIONS N.G. Lezhava, N.Sh. Dzagnldze, W.L. Dlmitrladl Dept. of Thermoohemietry, Institute of Inorganlo Ohemietry and Eleotroohemistry, Tbilisi, 380086, Jiokla 7. USSR The enthalpy of mixing ДНми ot Co-Zn, Hl-Zn, Li-Zn ferrites. Hi and Li ferroaluminatee were measured by means of the high temperature solution oalorlaetry teohnique on a Kalve- type oalorlmeter with solvent -3CdO-Pb*Oa-4Be03 at 970 K. The entropy of mixing and oonsequently the free energy of mix ing were found In terms of the experimentally established funo- л tions Cp=/(T) (above 298 K) by the semiepirioal oaloulatlon method. The results are represented in the table X ДН«и£ , ASmix . , AGaix kJ mol"* J mol'TC"1 HJ mol~* °r- 0.2 11.5 62 29.9 lt> 0.4 12.4- 17 17.4 0.5 9.8 29 18.4 ** 0.6 9.4 36 20.2 The wide speotra of structural and energetioal parameters of In vestigated systems and the analyses of the results in terms of iso morphio mixing energetioal theory, allows us to make following conclusions: 1) Solubility of the investigated complex oxide ferroepinela is exothermal, nonideal and irregular, with the factor of cations site preference energy prevailing over the sisse factor, while mix ing. - • 2) The rlghtnese of the way of the isomorphic» mixing energetioal •theory's further development for oxide ferrospinels indicated by prof. Urusov ia shown, making neoeseary to take into aooount the non-additive concentration dependence of bound's degree-of ionioity, while calculating the AHmix value". Reference 1) Zagareiehvili D.Sh. Methods of Oaloulation of Thermal and Elas tic Properties of Inorganio (Metallic Compounds."Mezniereba"- Tbilisi*i970,-190. 41 CALORIMETRIC INVESTIGATION OP HEAT CAPACITY AND FERROMAGNETIC TRANSITION OF RARE-EARTH IRON GARNETS V.S.Varaaashvili,M.S.Tsarakhov,T.A.Mirianashvili,T.A.Pavlenishvi- li.D.S.Tsagareishvili Institute of Inorganic Chemistry and electrochemistry of Georgian Academy of Sciences.380086,Tbilisi,Georgia,USSR. The heat capacity of rare-earth iron garnets JnJeJu*- with In - Sm,Eu,Gd,Tb,Dy,Tm were investigated by low temperature adi- abatic calorimeter (20 - ЗЮК) and by differential scaning ca- lorimetry DSC-111 (300 - 900K). The heat capacity data give us' possibility to calculate entropy,enthalpy and Gibba energy and to obtain information about thermodynamic properties of ferromag netic transition of garnets. On every С (Т) curve it was obtained A -type anomaly and Curie temperatures"-T of. garnets were established. Based on Neel's theory of. ferrimagnetism it was suggested the new method for determination the ferromagnetic contributions of heat capacity - Cb» According to the method С has been calcula ted using saturation magnetic moments data ana the values of heat capacity chenges at Cerie point - с (Т ). It was establiched that the thermodynamic caracteristics of fe rromagnetic transition, as magnetic heat capacity, enthalpy -<& H , entropy -AS and heat capacities chenges at T , are the same for all investigated garnets and their values don't depend on the ty pe of the lantanide ions. These results are in good agreement with garnets structure and their magnetic properties. It was Shown that in the series of rare- earth iron garnets in ferromagnetic ragion (T 3 5 12, Table Me3Pe5°12 C J/K.mol Pn 'T„,K 298.15 К 700 К с Sm 447 562 565 Eu 460 565 563 Gd 433 525 560 Tb 444' 538 556 Dy 443 527 552 Tm 444 528 ,535 42 THERMODYNAMIC CHARAC'J ЪШЕПСЗ OF VAPOuTll.OATIOll OF TOLLYL- AKI Hajn-u;n.ANE ( i-CFy.CgF^.SiMe,, (CgFc^ai). V.A.Titov,Yu.G.Stenin,T.P.Chusova Institute of Inorganic Chemistry of Siberian Branch of Academy of Science of UfcSR, Novosibirsk., U3SE. Phase equilibriums of solid-fas, solid-liquid and licuid- .gas of si lanes v.ere studied by the tcchnii.i:e of tbe quartz mem- '„•rane-O-pressure gauge measurements and calorimetry. i'he details of construction and of the operation were described previously' ' lhe iteiii feature of preparation Mid "nr.lysir. of silanos ..ere the sent' as''"'. For the tensimetric cxperiinentc the errors in the ma- t'Evrement of pressure end temperature jp.3 lorr and 0.5 К corres pondent!;/. From the experimental dates of unsaturated vapour pre ssure it was found that - both siianes existed in the vapour phase ac monomers: observed molecular mesea of tolly ls;ili;ne was 295+3 a.u. of phenjlsilane - 710*7 a.intheor.- 290.15 and 696.32 correspondent^); - tolly lsilar.e bet;.-11 i.o decompose et temperature above 63G K, phenyls!lane - above 670 K. For evapouration of tollylsilane it v.as found: LnP(evap., otM. )=1 c.367-5698.a/i' (296-460 K),^',2=15e/a'2-0.750/T+8.95.l0~4, 4Ke(T)='i7o'bj;0.21 kJ.mol~1,4 Se(i')=102.S0+O.5O J.K~1 .mol"1. For sublimation ;w*d ».!Vipouri.1 .ion of pheny.lsilane: LnPCsub. ,atm. ) = 26.ii0b-1l;4r.9/'l ('1^3-517 K)JC£&83VT+O.O1895-19.14/T,AH0(T)= 12 ..dVl.17 .vJ.mol-1, Дй°( 0=224.14-+2.26 J,К"1 .ш>1~1, LnF(evap., .•tn. -.1; .7:,.-VbV'Ub/i- ('I&J-565 K),^i5£b/l'2-1.97/I+0.00184-^He(T) =b0.i.o+i;.>o r-J.mol~1,Zl b°(j')=130.75+0.16 J.K~1.mol~1. Ur-int, calorimeter ГБС-111 CM'ARAIJ the temperature and en- thi-.li;/ of /"vein, hr-ve bi.en determined ts follows: 517.6 К and 46.9+u.: i.J.;iol -1 . These results are in very good agreement y.ith vopci'r vrecevre ке&еиА-евкмЛ . HEFiEU.Cb 1' 'i .i-'.Chusove, iu.G.Stenib,V.A.litov. Isv. GO IX SSSK, Бег.chin. ni.uk, t ''.11Д;\- 62. l . ) C.-o;.;l;cLr...i M....olo\ :'l.i,L..i.:.bes,J .Orubnotoet.Chet;;.-4- (1^65) 446. 43 THERMOCHEMISTRY Oi" JJRBIUM НАТЯ1Ч53. L.A.Tiphlova, A.5.iuonayenlcova Dept. of chemistry, Moscow State University, Moscow, USSR. Гhis work is continuation of systematic investigations of thermochemistry of lanthanides compounds [1] and deals with determination of the enthalpies of formation Er3+(aq), БгС1з(е) and ВгВгз(с) by solution calorlmetry. Enthalpy of reaction of erbium metal in 2,19 M HCI and en thalpies of solution of anhydrous ErCI^ in 2,19 M HCI and in water have been measured in a hermetic moved calorimeter at 298,15 K; (thermometrlc sensitivity of the circuit is 2 зс10~%). Total impurities in the erbium metal was estimated as less 0*42 mass-percent. Anhydrous erbium trichloride was prepared from Er20, by reaction with CCI*. From these measurements the following standard molar enthal pies of formation (kJ/mol) at 298,15 К were determined: Er^+(aq), (-681,8 + 4,5); ErCI3(c),(-968,3 + 4,5); ЕгВгз(с),(-812,9 + 5,0)» The standard enthalpies of formation of CI~(aq) and Br~(aq) [2^ and enthalpy of solution ЕГВГ3 at infinite dilution [3] were used for this calculation. REFERENCES 1. A.Monayenkova, L.Tiphlova, V.Goryushkin, JePhys.Chem.(Rues.) 63, Mo.4 (1989) 1079, 1082. 2. The thermic constants of substances. VIKITI Ac.of Sci-.USSR, Moscow, 3 (1968). 3. C.IIurtgen, D.Broun, J.Puger, J.Chem.Soc.Dalton Trans. No.1, (1980) 70. AA ENTHALPIES OP PORMATIOS OP SBagCu^ AND BaCuOg PROM OXIDES IJ.I.T.Catskevich, V.A.Titov, T.L.Popova, V.P.Shaburova Institute of Inorganic chemistry, Siberian Branch of the Aoademy of Sciences of the USSR, Novosibirsk 630090, USSR We wish to report the results of determination the enthal pies of formation of the YBa2cu^0x compound and barium ouprate from oxides. The experiments were performed in a dissolution calorime ter, which had an isothermal ehield. Used aa a solvent were solu tion prepared on the basis of 6 М hydrochloric acid. The tempe rature of the experiment (325 K) was chosen во ее to ensure that the time of the main period did not exceed 30-40 mln. The CRlorlmetrlo oyelee were designed so that the measured enthalpies of dissolution of the orthorhombic 1i2*3 phase could be compared with the dissolution enthalpies of the mixtures 1/2 Y203+ ЗСиО +.2ВаС03(1) and 1/2 YgO^ +CuO+ 2 BaCu02 (2). The use of such oalorimetric cycles allowe the enthalpy of for mation Of the 1:2(3 compound to be determined with a miniumum of reference data and also to perform an internal check of the ob tained resulte. The Y2°3* Cu0» ВаСОз materials used In the experiments were of speoial purity grade. A special thermal treatment was perfor med before use. The BaCuOg and YBa?Cu.Ox samples were synthesized A11 by solid-state reaction from BaCO,, CuO, Y2°3* material в hare been characterized by X-ray powder diffraction, chemioal and speotral analyses and represented Individual phases. The oxygen index in 1:2:3 samples was varied. Its value was estimated by X-ray structural method from the correlation between x and the unit cell value. The identity of the final states of the solutions was ohecked with the electronic spectra. The results of experimental work are given in table 1. It can be seen from the table that different thermodynamic oycles provide good agreement values of the enthalpies of the processes, thus indicating the absence of serios systematic errors in the measurements. 45 Table 1 Enthalpies of different reaction with YBa_CujO_ and BaCuOg, T» 325 К Reaction x дгН, kj/mol 1/2 Y20J+ зсхо + гвлаоу + 6.9 + 417+5 (x-6.5)/2 02 - 6.7 +440+5 Y BagCu^ + 2C02 6.6 + 457 +. 3 6.5 + 460+3 measured 6.4 +462+3 1/2 Y20-+ CuO + 2flaCu02 + 6.9 + 13+4 (x-6#5)/2 0, 6.7 + 36 + 5 Иа2Си3Ох 6.6 + 53 ± 3 6.5 + 56+3 measured 6,4 + 59+3 BaC03+ Cu0-BaCu02+ OOg +201+5 measured 1/2 Y203 +/3CU0+ 2BaO +. 6.9 - 122 i 5 (*-6,5)/2 02« 6.7 - 99+5 таа С 6.6 2 «3°х -82+3 6.5 -79+3 oalcu lated 6.4 -77+3 BaO + CuO- BaCuOjj -66+5 caloulated 46 STANDARD ENTHALPY OP FORMATION OP MoF-j(cr) BY FLUORINE COMBUSTION CALORIMETRY ' I.V.Timofeev,V.Ya.Leonidov,V.D.Butsky ,I.V.Rodionov, V.S.Pervov Institute for High Temperatures of the USSR Academy of Sciences, Kurnakov Institute of General and Inorganic Chemistry of the USSR Academy of Sciences, Moscow, USSR The literature data of the enthalpy of formation of crys talline molybdenum trifluoride are not enough reliable.There haa heen no previous calorimetric determination of this value,there fore the purpose of the present study was to determine it accura tely by fluorine combustion calorimetry. The energy of combustion of MoFo(cr) in high-purity fluo rine has been measured calorimetrieally.Preliminary experiments established that KoF^ underwent in part spontaneous slow fluori- natlon in high-pressure fluorine,therefore a two-chambered Monel met;l calorimetric bomb was used. The sample of molybdenum triflu oride contained (mass per cent): F- 37 »1 i Mo- 62.7 (the calcula ted values are 37.27 % and 62.73 % respectively).It did not con tain the noticeable quantities of any impurities including other fluorides or oxyfluorides (analyses were made by X-ray diffrac tion, infra red and X-ray electron spectroscopy methods). Purifi ed fluorine contained (volume per cent) : F5- 99.6 , &v- 0.2 ,05- d 0.2 and GC?- 0.1 . * • * The molybdenum trifluoride was situated into a prefluori- nated nickel crucible of special construction. The tungsten foil was used as auxiliary combustant.The initial fluorine pressure was 450 kPa. We had chosed the mass of MoF, in each experiment such that all the ЫоРс produced in the bomo was gaseous.The com bustion completeness of the MoF,(cr) in fluorine was 99.6-99.9 %» It was determined by the weight^of unburning solid residues,HobV and WPg were found in gaseous products only. The necessary corre ctions were taken into account including tho correction AUjblank) for expansion of F from external chamber of the bomb into the reaction chamber. 2 The enthalpy of reaction MoP,(cr) + 1.5 Fa(g) • MoIV(g) was calculated from 7 experiments :JA Я (298.15 K) = - 600 ?4 * . * 3.4 kJ'mol"1 (the uncertainty is 95 per cent confidence inter val). Combination of this result with AJtJ value of - (1557.7 - - 0.9) kJ.mol"1 for MoFg(g) has yielded the standard molar en thalpy of formation of crystalline molybdenum trifluoride « AfB° (MoFvcr,298.15 K) = - (957.3 * 3.5) kJ.mol-1. The'value^of enthalpy of formation of MoFc(g) was taken from the book [1j . REFERENCES 1) V.Ya.Leonidov,V,A,Medvedev. Fluorine Calorimetry. Nauka i Moscow . 1978 . 47 • Jb'TIIAIiPUS Cli' FORMAIIOK OF SImPLii jiiii) CUiPLiJ.,. LAI.TiUi;iJ.5 0::IDJ>W AH3 IHiiffinOCiliiiillCAL CO.^JLATIONS Yu.L.Suponit Ski Dept. of Inorganic Chemistry,Faculty of General Technique, Uendeleev Institute of Chemical Technology,Moscow,USSR Some lanthanide compounds,oxides' and derivative lanthanide oxides,complex oxides and salts are used in technology of mate rial:-:' (phosphore,high-Te superconductors and other). Today we have a significant base thermodynamic properties of individial lanthanide compounds. These properties differs on correctness. , The calorimetric schools of different countries were es tablished data about 30 lan+hanide oxides, in eluding nonstei- chimetric oxides,oxosulphides,molybdatestchromates,niobates, tant .alates.zirconates, tungstates.aluminates,borates and other In this communication there has been made the systematic review of all literature and own data on the enthalpies of formation. From the analysis of these data the most reliable values are selected. The recommended values with their uncertainties of standard enthalpies of formation in crystal state are presen ted. There are recommendations to continue experimental measure ments on standard enthalpies of formation some compounds,for example,taritalates and niobates. Since many lanthanide oxosalts are insoluble in acidic and other solutions except some melts,that methods of thermo - chemical correlations are essential for estimation enthalpies of formation many lanthanide oxocompounds. Some correlations are useful for estimation other properties. enthalpies of formation of chromates,molybdates and other were estimated by thermochemical correlations. Therraoehemieal correlations were ussd to compare proper ties of lanthanide and actinide oxocompourids,to arrange yttrium and scandium in lanthanide family. 48 THE STANDARD MOLAR ENTHALPY OF FORMATION OF GADOLINIUM TRIIODIDE. M.E.Efimov, M.U.Furkaluk Institute of High Temperatures, Academy of Sciences, Izhorskaya 13/19, Moscow 127412, U.S.S.R. V.F.Gorushkin Siberian Institute of Metallurgy, Novokuznetsk. Literature values of the enthalpy of formation of Gdl^Ccr) have large discrepancies and are based on estimations. In the present work the enthalpy of formation of Gdl^fcr) was determined by calorimetric measurements of solution of Gd(cr), Gdl^cr), KI(cr), KCl(cr), HaO(l) and HCl(sln., 55.38Hao) in 1 mol/dm* HC1 at 298.15 K. These six reactions performed closed thermochemical cycle. Gadolinium triiodide was synthesized by heating of Gd shavings (99,77% of purity) at 1220 К and crystalline iodine (99,99*. of purity) at 490 К in two chamber quartz reaction ampoule under vacuum of 5-10~* Pa with further purification by driving off iodine at 1000 К and 5 10"5 Pa. The sample of 6dl5 was analyzed by volumetric titration for Gd and gravimetric analyses for iodine ( found: 29.22*0.05 and 70.5110.25 per cent; calculated: 29.23 and 70.77 per cent accordingly ). The measurements of enthalpy of reactions were carried out in the 0,1 dm3 reaction vessel of an isoperibol calorimeter LKB- 8700. The design of the calorimeter, control measurements with standard substances and the calculation method have been described elsewhere [1]. All operations with samples were made in a box filled with dry nitrogen. The ampules were weighed on a microbalance "Mettler M5SA" to 10.01 per cent. Before each experiment the calorimetric solution was saturated with a flow of hydrogen during 15 min. The values of enthalpies of reaction of Gd with HC1 solution were corrected for the enthalpy of vaporization of solution in hydrogen evolved in these reaction. The final reaction of the thermochemical cycle was Gd(cr)+3KI(cr)+3HCl(8ln.55.38Ha0)«GdIft(cr)+3KCl(cr)+1.5Ha, дгНв —438.8940.76 kJ/mol. The following AfH* of KCl(cr), KI(cr), HCl(sln.55.38Ha0) are known: -436.49±0.13, -329.3010.17 [2], -16S.37i0.ll kJ/mol [3]. These values were used to calculate e AfH (GdI(5,cr,298.15 K) - -(613.43 ± 1.0) kJ/mol. REFERENCES 1) V.Medvedev, M.Efimov, Zh.Fiz.Khim. 49 (1975) 1324. 2) V.Glushko, L.Gurvich, et al, Thermodynamic Properties of Pure Substances, vol 4, Nauka: Moscow, 1982. 3) V.Parker, Thermal Properties of Aqueous Oni-Univalent Electrolytes, V.s. National Bureau of Standards: Washington, D.C. 1965. 49 CALORIMBTRIC STUDY OP THE Ba-Sr CARBONATES L.P.Ogorodova, I.A.Kiseleva, L.V.Melchakova Dept. of Geology, Moscow State University, Moscow 119899, USSR Thermodynamics of solid solution and end-members of stron tium-barium carbonates have been studied by heat-flux Calvet ca- lorimetry. Samples of strontium-barium carbonates with their com positions between BaCO, and SrCO, were prepared in hydrothermal apparatus at 700°C and 2 kbars in water carbon dioxide fluid (with mole fraction of carbon dioxide ==0.01). The enthalpies of solution of the samples have been measured by oxide melt calori- metry at 700 С in lead borate 2PbO*B20,. 10-30 mg of the sample material was dissolved in about 30 g of the flux. The measured enthalpies of the solution were typically in the range of 5-10 J (endometric). Calibration of the calorimeter was achieved by dropping pieces of platinum wire. The mean solution enthalpy mea surements for a solid solution, end-members.and their mechanical mixture of BaCO, and SrCO, are shown in Figure 1 as a function of the composition. The Ba-Sr carbonates solid solution shows a negative departure from a linear variation between the end-mem bers, which corresponds to a positive enthalpy of mixing. The maximum of enthalpy of mixing at Xfi =0.35 is near 4.8 kJ/mol. The dependence of the enthalpy of mixing as a function of mole fraction of barium carbonate' can be described by two- parameter Guggenheim model equation: "' AH = mix ХВа(1-Хаа)/(1б.5+0.6)+(Н.2+1.4)(1-2ХВа)/ kJ/mol The dependence of the enthalpy of mixing on the concent ration is shown in Figure 2. From the experimental data of heats of solution according to Hess'law the values of entalpies of formation of BaCO, and SrC03 were calculated! -1209.9 +5.8 and -1231.4+2.0 kJ/mol respec tively. ~ ~ **&,- *W' tl&i*. *-?W mo 2Sf • mo 0S5 e£.o 02 0.6 02 06 Figure 1 Figure 2 Ж 50 THE PRECISION BOMB CALORIMETER WITH AN "INERTIA-FREE" THERMOMETER E.G.Lavut, M.V.Chelovskaya Chemistry Department, Hoscow State University, 119889, Hoscow Earlier we have described1-2 the calorimeter supplied with a copper resistance thermometer with a very small time constant end untraditional procedure for calculation of experimental result?. Those apparatus and procedure provided high pracision of measurements even if conditions were far from optimum which usually used in calorimetric practice. Below we describe the results of investigations of the possibilities of che instrument and method in conditions which are . absolutely unreal froe point of view of classical calorimetry. The following conditions were chosen: the difference between the temperatures of water jacket and calorimeter in the begining of main period was 5 K, the initial period lasted for 2 h, the total duration of the miin and final periods was 6 h. The calculations were performed with different length of main period from 1.5 h to 3 h, the correction for heat exchange being varied approximately from quarter to half of useful hsst «ffect fin our experiments the energy equivalent was measured, the energy being supplied electrically). The calculations were made with seven values of length of main period at fifteen-minute interval?. The reproducibility of the results obtained have to serve as a criterion of correspondence of t,he scheme of calculation of the correction for heat exchange and real physical phenomenon taking place in the calorimeter. If the calculation of this correction is well-founded physically, there shouldn't be generally sneaking the influence of the duration of •ain period on the results. Here are the average results of eight runs on measurements of the energy equivalent, J/Ohm 'the uncertainties are given for a 95 per cent confidence interval): 119463*22, 119431-'27, 113480*14, 119309*54, 119447*20, 119444*34, 119395*27, 119351*64. It should be noted that the testing of results by Cochran's criterion points with a certain probability to unhomogeneity of variances obtained in theese experiments. The conditions of performing of each run were dust the same, so it ws? possible that the reason of unhomogeneity pointed above was the perceptible contribution of convection into heat exchange botneun water jacket bnd calorimeter, especially taking into consideration the largo temperature difference between them, because f.he coivectivo heat exchange isn't stable and hi.4 dependence on temperature isn't described by quadratic equation as wa:; postulated in our calculations. In order to check this assumption six runs were performed in which three concentrically arranged copper screens were placed between the calorimetric vessel and jacket, so the space between them was divided into five narrow zones where oonvective heat exchange should be impeded. The following results were obtained: 11969Г-»8, 11984$i39, 119752*10, 1197?4г25, 119901*34, 119864*16. (The ;arge discrepancy of the absolute values is not important because it was duo to technics] reasons only). It is evidently that the reproducibility of the results in each run became appreciably better. Examination h/ Cochran's criterion showes the absense of failed valtifs on Ь pee een', level of significance. REFERENCES 1) E.G.Lavut. N . V .Chslovskaya, J .Checi .Thermodyramio4 . ?,\ (1989) 765 2) E.G.Lavut, N.V.Chelovskaya, ?h.rhysiohi?.-koi chim:.,63 (1989) 877 51 THE ENTHALPIES OF FORMATION OF LEAD SULPHIDE AND OF TRINICKEL DISULPHIDE IN REACTIONS OF SYNTHESIS INITIATED WITH •ASER RADIATION L. M. Vidavskii Dept. of Chemistry, Moscow State University, Moscow, 119899, USSR Л calorimeter for precision measurements of the heats of diverse laser-initiated '•'..emii'al re-ictions has been built. The method of determination of the standard (л'ЬгЛру of formation has been proved; lead monosulpbide and trinickel disuiphide ie;ved the purpose as the corresponding products of syntheses formed in a calorimeter. Principle of experiment- For determination of total heat quantity a massive '•, ...Mineter is used. Inside the calorimeter it is placed a reactor supplied with an entry fin bt.ser beam. A chemical reaction commences after its initiation with laser radiation in the principal calorimetric period, in two other periods a chemical system is near the ;i.andnrcl temperature. Quantity of laser radiation energy participating in reaction initiation is measured by an independent method. The components or a chemical system being iii the form of powders are mixed in nitrogen atmosphere and pressed. A reactor with tablets obtained is evacuated and filled with pure argon. An excess of metal component is used in both of reactions. Therefore quantity of the product formed in a «lorimetric experiment is determined by an appropriate analytical procedure. The lii.'^nnination of sulphide ion quantity is a sufficient procedure because of a) each "lUlphide is the only reaction product which forms in conditions of calorimetric experiment, b) the composition of sulphide formed is quite constant, the limits of phase homogeneity being a negligible factor in calculation. Features of laser initiation of chemical interaction, A laser pulse acting on a tablet • :ther melted one/both of its components or it caused no melting. A favorable result WHS adjusted with factors such as the pulse energy, the irradiation area on a tablet and м> on. Both of the reactions products were difficult objects for synthesis in a calorimeter bocause of sulphur volatility, this negative factor was not eliminated in the experiments. For the system lead-sulphur the conditions of radiation heating were fitted in order ;=J minimize quantity of the melted metal. Therefore the chemical interaction of solid lead with liquid (and gaseous) sulphur took place in the main. Lead removal out of a reaction zone was almost eliminated in this way. Also an optical device served this purpose, even distribution of light energy was formed on a tablet surface. In spite of these precautions the yield of lead sulphide was very small in a single tablet. Therefore rour tablets were used in a calorimctric experiment each tablet was irradiated with a single pulse. The yield of trinickel disuiphide was quite enough and the precautions inoiuioncd were unnecessary. The components of this mixture were capable of sufficiently strong exothermic interaction. Reactions of this type are characterized by . .If-prop:igiiiion: initiation is followed by the formation of a high-temperature zone and i"-- preparation throughout the whole volume of the mixture. The standard enthalpy of formation of lead sulphide. Energy equivalent of ••J.tritr.cter (24754.±14) J/Ohm. Sixteen runs were made, the average values: total heat -,u-'.i!t:ty 63.1 J, radiation energy quantity 55.0 J, mass of the product 20.0 me. afHVmsK (PbS,cub.) = -(97.0+2.9) kj/mol. The standard enthalpy of formation of trinickel disuiphide. Energy 3tit>ivii!cnl (24036+29) J/Ohm. Nine runs were made, the average values: total heat q'.'i.'iti:/ 167,8 J, radiation energy quantity 22.4 J, mass of tie product 140 mg, correction for impurities (1G.+0.7) J. *>№"тик (Ni3Sj, hex, heazlewoodite) = -(2266+22) kj/mol. 52 HEAT CAPACITY AND THERMODYNAMIC FUNCTIONS OF Fr-O, AND TWO MODIFICATIONS OF Eu,0„ FROM 5 TO 300 K. Lutsareva U.S., Bergman G.A., Institute of High Temperatures of Academy of Sciences, Moscow Naumov V.H., Berezovsky G.A., Institute of Inorganic Chemistry, Siberian Division of Academy of Sciences, Novosibirsk The heat capacity of Pr20g and B- and C-modifications of Eu_03 was measured from 5 to 300 К by adiabatic calorimetry. A sample of hexagonal praseodymium sesquioxide was used of 99.8% purity. The heat capacity was measured in a vacuum adiabatic calorimeter with periodic input of heat[l]. About 80 experimental points were obtained. The extrapolation to zero absolute 3 temperature was made using T law. No Shottky anomaly was observed at low temperatures. The Debye temperature near T=0 was defined constant and equal to 284 K.. A sample of B-Eu_0, (monoclinic modification) was prepared from commercial C-Eu20g (cubic modification) at 1500 К by heating during several hours. About 100 experimental points for both samples were obtained with an average deviation 0.1X from smooth curve above 30 K. Cp.J/mol.K S°,J/mol.R HC298.15 K)-H<0),kJ/mol Pr203 121.6*0.5 153.8350.5 23.002+0.05 B-Eu203 122.4+0.5 142.68*0.5 22.380*0.05 C-Eu20g 127.2*0.5 141.47*0.5 22.580+0.05 The low temperature heat capacity data and the data on enthalpy at high temperatures [2,3] were used for recalculating the enthalpy of transition between two modifications. References 1.Naumov V.N.. Nogteva V.V., Paukov I E.,Preprint INKh SO AN SSSR B3-3, Novosibirsk, 1983, 21pp. 2.Tsagareishvili D.SH..Gvelesiani G.G..Zh.Neorg.Khim.,1965,10,2,319 3.Pankratz L.B.. King E.G.. Кe 1 1 ey K.K.. BuMines Rl 6033,1962,18pp. 53 DIRECT CALORIMETRIC MEASUREMENT OF ENTHALPY OF ' FORMATION OF MOLIBDENUM BORIDE IN REACTING SHS-SYSTKM Mo-B E.G.Lavut, N.V.Chelovskaya Thermochemistry Laboratory, Moscow State University 119899 Moscow, USSR О,E.Kashireninov Institute of Structural Macrokinetics. USSR Academy of. Sciences 142432, Chernogolovka, Moscow Region, USSR Precision determination of SHS thermal effect in equimolar powder mixtures of molibdenum and amorphous boron was carried out using water bomb calorimeter with an electric microfurnace i. The reaction mixture was placed into .sealed quartz ampoule contained a small amount of МоОэ for facilitation of SHS-proeess. The reaction was initiated by heating the sample in the microfurnace with platinum heater. The start of SHS-reaction was checked by sharp increasing of the heater resistance, then the microfurnace was switched off. After the end of each calorimetric experiment concerned with SHS-synthesis the bomb was not disassembled but was used for determination of the energy equivalent of the calorimetric system. The energy equivalent was determined twice : the absence of significant variation between the results of the determinations can serve as a corroboration of lack of additional thermal effects due to the uncopleteness of reaction. X-ray analysis demonstrated that both tetragonal (i ) and orthororabic ( fi) modifications of molibdenum boride were present in the reaction products. -The enthalpy of reaction measured in various runs was constant in spite of the considerable dispersion of £ - and f> -phases content. This allows to suppose that the heat of S -fi phase transition is small enough and have the order of the accuracy of the performed measurements. The obtained results gave the value of enthalpy of formation of molibdenum boride д rH° (MoB, cr.. 268.15) = -103.9 *. ± 1.2 kJ/mole. REFERENCES 1) E.G.Lavut, N.V.Chelovskaya, J.Chem.Thermodynamics. 21, (1989> 765 54 THERMODYNAMIC CHARACTERISTICS OP THE OXIMOLYBDATBSOP La, Nd, Sm, fiu AND 8d V.M.LAZAREV, LI KUM Department of General and Inorganic Che mistry, Mendeleev Institute of Chemical Technology, Miueskaya pi., 9» Moscow 125820, USSR The oxymolybdates LugMoO, ( Ьпш la, Nd, Sm, Eu and Gd> were prepared by cooking oxides of molybdenum and lanthanidee la ra tio 151 at the temperature range 400- 1200° С The tablets were prepared under the pressure of 1*10 Ba and were heated at 500 С for 2 hours. The oxymolybdates samples were investigated using the X-ray powder-diffraction analysis and IR-spectroscopy* The high :temperature enthalpies and heat capacities of the samples were determined at the temperature range 298- 1000K by means of high temperature differential heateonducting calorimeter by droft- method* . The obtained results are in the table.. Series T,K Hj •• ^98,15* W»"*-1 LSjMoOg HdgMoOg SSUllOOg ISUgUoOg fldgMofig* 1 3173,15 16,04 16,19 15,68 17,13 2 473,15 36,07 36,42 36,68 38,38 35,59 3 573,15 56,36 55,78 59,42 59,94 . 56,24 4 673,15 77,49 77,45 80,46 82,06 75,97 5 773,15 100,94 102,39 103,97 105,44 100,39 6 848,15 119,73 118,70 123,28 126,02 117,49 7 923,15 140,87 141,19 147,07 147,01 134,57 SPECIFIC HEAT OP (HTSP) YBa^UgO^Clg^ . FHONON AND ELECTRON CONTRIBUTION E.B.Amitin, n.V.Voetrikov, V.N.Naumov, P.P.Samoilov, S.A.Slobodyan, K.S.Sukhovey, V.E.Fedorov, G.I.Frolova Institute of lnorganio ohemistry, Academy of soienoes 630090, Novosibirsk, USSR A considerable number of researoh is devoted to the proper ties of YBa2Cu307_g oeramios (123) doped by the halogens. Never theless it Is evident that the modification of their phonon and eleotron properties resulting from the doping has been investiga ted insufficiently. In the present work the temperature dependence of speoific heat of Cl-oontaining (123) oeramio has been investi gated for the aim to find out the effeot of ohlorlnation on phonon and eleotron oharaoteristios. The sample was prepared by ohlorlnation of the rhombio phase YB^CUgO^g by means of PC15 in the eoldered ampule at 160°C for 4 hourB (proportion of the reagents has been ohosen 1:0.3, respec tively). After the end of the reaction the fugitive products have been pumped out (at 10~г mm Hg pressure and 120°C), the sample has been washed with aoetonitril, ether and dried up in vaouum. The phase obtained was identified by means of elementary and X-ray analyses. Aooordlng to these analyses 01-oontaining phase has the rhombio lattloe with parameters a=3.83 1, b=3-83 I, o=11.7 A, wioh are olose to those of the ordinary rhombio (123) oe ramio. in the angle region from 4° to 65° no admixture reflexes have been detected. Aooordlng to neutron diffraction analysis one half of introduced chlorine atoms oooupy the vaoant position 0(5) in the Ou-0 chains. Another half substitutes oxygen. Thus ohlorinated oeramio composition oan be desorlbed by the formula *Bl8.O10lb.«O6.5401O.61-' The specific heat measurements have been performed in an adiabatio calorimeter between 7 and 300 К using a step, heating. 'i-he temperature riee is 1-4 K; in the phase transition region t'Tc=91.7 K) it varies within 0.3-2 K. The results in the phase •transition region are shown in Fig. In a wide region around T (31-110 K) the measurements of С (Т) have been also carried out by "he continuous heating method with the rate of 0.05 K/min. Л year 136 later с (Т) WP measured опое more In the normal state region (T>T ) to oheok the reproduo- С W'K" Q А tlon of results In the oourse т of time. Results were found to 0,100 J be exaeotljr the same wlhtin the experimental aoouraoy. The separation of the ».•*••' lattice and electron contribu Л* 0,093 - tions above T have been made Г by a method based'on the high- temperature expansion of C(T) in powers of ш/Т. In it the eleo- &S 90 95 Т,К tron speoifio heat ooefflolent 7 as well as the phonon speo- trum oharaoterlstlos 62 and вд, oonneoted with even power momenta of <•) are found simultaneously [1]. The results of the analysis performed are given In the Table. 7. mJ mol-1 K"z 37 1 2 83 ± 18 К 440 t 3 440 t 20 в?. It oan be seen that introduction of chlorine into (123) ce ramic modifies insignificantly the parameters of the phonon spectrum (&z, QA, e„) and appreoiably increases electron speoifio hean coefficient 7. Superoondaoting properties (superoonduoting phase concentration estimated via the apeoifio heat jump), are not Improved. Apparently chlorine doping results in the formation of the narrow band In the Cu-0 ohains with high density of states. 1. Haumov V.H. and el. tf.fis.oUimii,1i)Oe,v.62,Jt1,0.25-29- 57 HEAT САРА01ТУ OB NIOBIUM HALlUfiS IN 5-300 К RANGE G.A.Berezovsky, L.M.Bazhanova, O.I.Vlaskina, A.N.Oolubenco, I.E.Paukov, S.V.Sieoev r Institute of Inorganic Chemistry, Siberian Division ов the USSR Aoademy of Soienoe, Novosibirsk, USSR The samples of niobium halldes have been obtained from high- purity starting substanoes, subjected to an additional purifica tion and characterized by the results of ohemloal and speotrosoo- pio analyses. Isobario heat oapaoity Cp In the 5-300 К range has been measured In a vacuum adiabatio calorimeter with periodic in put of heat. About 100 experimental points for each sample have been obtained with an average deviation from 30-300 К range which Increased up to 0.5 per cent below 30 K. C°(298.15 K) S°<2?8.15 ) H°(298.15 K)-H°(0) J mol-1 K~1 J mol"1 K"1 J mol-1 15320 Nb«2>33 84.59 98.35 18950 NbCl3[13 98.54 127.5 19360 NbBr2>*79 90.91 138.2 m>Br 126 4 207 3 27610 *!o4 * ' 34100 NbBr " 152.6 268.8 5 29870 ЯМ, 129.4 238.5 37280 Hbl5 158.2 311.1 НЬХд and NbJ^ halidee (X-Br, I) have no anomalies in their heat' capaoity. A speoifio feature of polyatomio niobium chloride №601u (NbCl2>33) is the presence of the HbgCl12 groups in wioh six atoms of metal form an ootaedron. These groups are linked to gether via ohlorine atoms and form a layered structure. According ly, the heat oapaoity of Nb6Cl14 within 20 to 70 К range ie pro portional to T2. Below 10 К there ie, in addition, an anomaly in С of unknown origin. The composition of Nbfil1 3 corresponds to the upper limit of the homogeneity region of the "triohloride phase', the lower limit being occupied by Nb_Cl„ (Nb Cl_ ,_). This niobium ohloride, ae 4 well as ЯЬ6С11Д, has a layered structure '.The С~T dependens is not observed In NbCl3 13 indicating a distortion of the layered struoture with increasing ohlorlne content. The behaviour of heat oapaoity of NbBr. 7g suggest that in this oompound the layered struoture is missing too. 1. A.Tagaev, L.Bazhanova, G.Berezovsky. J.Thermal Analys. ЭЭ (1988) 217. 56 THERMODYNAMIC PROPERTIES OF ADDUCTS OF NICKEL CHLORIDES WITH UREA WITHIN THE INTERVAL OF 8 - 320 К D.U. Usubalijev, K.Sh. Abdyldajeva, M.B. Batkibekova, I.Je. Paukov, G.A. Berezovskii, B.B. Smambekova Polytechnical Institute, Frunze, USSR Institute of Inorganic Chemistry, SO Academy of Sciences of the USSR, Novosibirsk, USSR For the first time there were obtained the experimental data of the heat capacity of nickel chloride adducts NiCl_- 2CO(NH-)2 (1), NiCl,-'4CO(NH,), (II), NiCl--10 CO(NH-), (III) in the'temperatufe range from 8^t» 320 K. . ' The heat capacity of nickel chloride adducts was measured by the the adiabatic method/1/. The ampule for the compound (useful value -6 cm) is made ofnickel and sealed by the screwing cap and shim made of ortezoneplast. The temperature was measured by the platinum resistance thermometer of TSPN-4 type. On the basis of smoothed values of heat capacities С (Т) there were estimated the entropy, the differences between the Penthalpies and the given Gibb's energy and common values of thermodynamic functions at 298,15K are give in the table. The solution enthalpies of adducts NiCl- nCOtNH,), in the 0,1 N water solution of HC1, and also solution enthalpies of Nicl2-2H_0 in the urea solution and solution enthalpy of urea in the Solution of nickel chloride were measured on the microcalori- meter with the isothermic envelope. On the basis of obtained experimental and reference data of the reaction (a) there were estimated the standard formation enthalpies of a_H /298,15K/ adducts NiCl,- nCO(NH,)_ (see the table): NiC1 + nCOlNH , NiCl nCO(NH ) (a) 2(er) 2 2 COMPOUNDS J-mol-1 • K~' J-mol"1 kJ-mol"1 (*p(T) S°(T) F°(T> н°(т)-н°(0) ; -Л£н° NiCl2-2CO(NH2)2 275.6*0.2 296.0*0.3 143.1*0.2 45570*50 1031.3-1.3 NiCl2-4CO(NH2)2 471.9*0.4 523.2*0.4 261.0*0.2 78184*50 1730.9*1.4 NiCl2'10CO(NH2)2 571.5*0.5 168800*100 3798.9*1.4 The general view of temperature dependences of heat capacity C Cp(T) is shown in the given coordinates _/3R in the figure 1. For all three compounds the dependence С IT) is represented by the smooth curve without any features inpthe temperature range. 59 • V •' ... * - ниJ.W1»,), • ••«1,.о.. f л Fig.l Fig. 2 The analysis of Debay parameter в_(Т) (fig.2) allows to pro pose the presence of various energies of menatomic interactions in the researched compounds. It may be explained by the anisotropy of their crystal structures, as for the isotropic compounds the quantity does not depend on the temperature. The fact that 6Q(T) is the monotonic increasing function for all studied compounds shows that unharmonic contributions with С (Т) in the whole temperature range does not excess the error of the experiment, since at.the more significant unharmonic contributions the sign of derivative в_(Т) is changing to negative according to the temperature changes. He must note also that the increasing of urea molecules quantity gives the increasing of the Debay parameter quantity and in this case the quantity of В below 100 К does not change practically. It means that the invasion of urea molecules mostly influence the high temperature thermodynamic properties of researched system. REFERENCES 1) Bazhanova L.M., Berezovskii G.A. Paukov I.Je. and others, j. phys. chimii, В (1988) 2035 60 THERMODYNAMICS OP BORAZOL IN THE RANGE О К TO 310 К T.G. Kulagina, B.V. Lebedev Chemistry Institute, Mil. lobachevsky State University, Nizhny Novgorod 603600, USSR The temperature dependence of heat capacity (C°. „) of bora- zol M j^^^which is occasionally referred to as inorganic ben- I Lzene has been studied from 13 to 310 К in a vacuum igii adiabatie calorimeter to a precision of 0.2 # (Fig* ЛЯЯ Fig. 1. Heat capacity of borazol: 1 - crystalline; 2 - liquid. Its temperature and enthalpy of melting were determined Tfus"215-76±0-0/l K'' AfusHS/R*K*'l276:!:^; AfusSS*5*9±0-2* From our calorimetric data the total content of impurities in the sample under study is found to be 0.60 mole 5». Thermodynamic functions were calculated in the range 0-310 К from the data ob 0 tained. At Т.298И5 К and p-101.325 kPa C ,m /R.17.64; A£H°/R.K= 3995; A^S°/R-2*.10; , dfn°/K K=-C>5970; UfS%/&=-59.5)i ^fG°/W K--48.20 (liquid borazol). The properties of borazol were compared with those of ben zene С2,3J. They proved to be close, however, Trns^C6HC^ is т В higher than ?иа( 7,^з%) by 63 K. The analysis of contributions of lattice and atomic vibrations into the heat capacity (i'ig. 2) showed that the differences in the heat capacities between bora zol and benzene were due to mainly their unequal contributions into C° £ and cf-C^. Lattice contributions into the heat capaci ty of both compounds are similar. Fig. 2 Components of heat capacity of borazol and benzene: 1 and 2 - Cy5 3 and 4 - Cv iatt#i 5 and 6 - Cy fit for borazol and ben zene, respectively. REFERENCES 1) M.V. Kilday, W.H. Johnson, E.J. Prosen, J. of Research Nat. Bur. of Standards. 65A (1961) 101. 2) D. Stull, E. l.'estrum, G. Sinke, The chemical thermodyna mics of organic compounds. Moscow: Mir. (1971) 41J. 3) I.B. Rabinovich. The effect of isotopy on physicochemical properties of liquids. Moscow. (1968) 184. 62 LOW Ti-HPKaATUHii НЙА'Г CAPACITY, TIfciKKOflYNAMIC FUNCTIONJ, ENTROPY AND GIBHJ iiHjfiKGX . 01!" CHJJMICAL BOHD OJ? ALCYL COMPOUNDS OF P, As, Sb, and Bi. V.P.Nistratov, I.B.Habinovich, M.d.oheiman Chemistry Institute of Lobachevsky State University, Nijny Novgorod, UJJK. The temperature dependences of the heat capacities of (C2H5)5P, (CHjJjAe, (OgH^jAs, (C3H7)3As, (OgH^Sb and (CgH^jBi have been studied in a vacuum adiabatic calorimeter [1] over the temperature range 5 to 300 K. She error in the heat capacity was less than 0,2^ above Зо К. In the temperature range studied each compound is in crystal line and liquid states. Its heat capacity in the crystalline state increases gradually with rising temperature, a break in the plot of С against S being due to the fusion of the compound. Thepthcrmodynamic quantities of melting are listed in tablel. She enthalpies of melting (&*. H ) were measured by the method of continuous energy input. The^ equilibrium temperatures of melting (Т2 )for the substances of 100 per cent purity were obtained from thau§ay experimental equilibrium temperatures of fusion for the simples studied depend on the fraction melted. A is the first cry- oscopic constant A= ufugH /H(Srus). Table 1 л -1 H° kJ то1- T K S H A, K Compound fus f fus» fus ? (C2H5)3P 10.732 188.16 6.860 0.03646 (CII5)3As 8.962 186.60 5.777 0.03096 (C2lij)3As 11.06 181.8 7.317 0.04025 (CjH7)3Ae 14.60 180.15 9.7*7 0.05410 (u2n5)3sb 9.352 153-9 7.309 0.04749 (C2lI5)3Bi 8.695 145.80 7И73 0.04929 To calculate the thermodynamic functions the heat capacities of compounds studied were extrapolated to О К .with the Debye fun ction for heat capacity. The functions H (T)-H°(0) and S (T) were calculated by numerical.integration of С =f(T) and С =f(lnT) by using a computer and G (T)-H (0) are calculated byp the Gibbs - Helmgoltz equation. She results are listed in table 2 at Т=29Й.15 К. Prom our calorimetric results by using the literature values of the standard molars enthalpies of formation and the vapour pres sure of the studied substances f2] we calculated the standard molars entropy Л-3 and Gibbs energy &~G of formation of each compound_in the liquid and the gaseous states as well as the mean entropy ЛЬ(Е-Н) and Gibbs energy AG(E-E) of the dissociation of the chemical bonds element-alcyl. The last values were calculated by the equations: Kj£(g) « 5H(g) + E(g) and AG(ii-R) - 4pG°/3 as(E-a)» arsV3 63 The results at T=298.15 К are listed in table 3. Table 2 Heat capacity and thermodynamic functions of alcyl compounds at 298.15 К Compound .H°-H°(0) [G°-H°(0)] CP s° r-K"1mol"1 kJ.mol' -1 (C2V3F 236.3 329.9 51.80 46.55 (GH3)3As 154.0 251.3 37.90 37.02 (C2H5)3As 238.0 353.5 53.97 . 51.45 (C3iI7)3As 326.0 454.5 71.60 65.39 242.5 368.0 54.81 54.85 (с2и5)3зь (c2u5)3Bi 242.5 379.0 5*.89 58.11 Table 3 Standard molars entropy and Gibbs energy of formation of the studied substances in the gaseous state and the mean entropy and Gibbs onerGy of the dissociation of the chemical bond element - aUtyl at 298.15 К S° - AS(E-H) Д G(E-H) Compound 1 1 J.K" •mol kJ mol" (CgH^jP 423.3 165.0 138.o 180.9 (CH3)3As . 339.9 138.6 101.4 193.4 (C2H5)3As 435.1 164.6 237.3 135.0 (CgH^Sb 464.4 156.9 223.3 133.0 (C2H5)3Bi 481.6 153.4 388.5 60.2 Any regularities and correlations of the dependence of the thermodynamic properties of the studied substances depend on the nature of element and radical were obtained. HivFjSHiSNCJiS 1) I.B.Rabinovich, V.P.Histratov, M.S.Sheiman, and G.V.Surohalova, J.Chem.Theraodynamics 10 (19/8) 523. 2) V.P.Nistratov, I.B.Habinovich, Application of Organometallic Compounds for Production of Inorganic Coating and Materials. Nauka: Moscow. iy*«Sf p.p. 34-50. (Ч MAGKETOCALORIC KFFEtT IN HTSC .MATERIALS A.M.Kykov, V.i.T.Yuzhelevskll Donetsk Physlco-Technical Institute of the Ukrainian Academy of «Sciences, 340114 Donetsk, USSR. If a type-il thermally Insulated superconductor Is exposed to the magnetic field H > Hcl A§ C„ &T _ _ dHoa/dT н ~ " т и в% ae* where Cp is the heat capaslty per unit volume, dH=i/dT - is the slope of upper critical field, Ж - Is the Glnsburg-Landau parameter. Thus, the measurement of the magnetocalorIc effect makes it possible to find a combination of Important parameters a (dHe3/dT)/ae , which are hardly found in HTSC because of the lnhomogenelty of the sample structure. high anisotropy and high H„a. A cell similar to that of the adlabatlc calorimeter has been designed to investigate In fields up to 4T. Besides in the same cell the resistance by the foui—probe method may be measured.The minimal mass of samples is 0.2 g. The relative accuracy of measurement is about 20 per cent. Flg.l shows the results of finding magnetocalorlc effect for two different. hl.gh-T«. materials . As/H gets a slight change above a certain temperature for both compositions.Pro bably just, above thin temperature the Glnsburg-Landau theory mav be applied. Tim Increase of magnetocalorlc effect near Tc is due to the Inhomogenelty of ceramic samples. Because of this lnhomo- genelty the Abrlcosnv vortices at structural defects start contributing to magnetocaloric effect near Tc only, when co res of tho vortlres broaden greatly. Thi» MPAsiir*>m<-nts of ruaqrietoreslstance make It possible to find dH^.'dT and thus. £. For (BIPb)a Srа Са^ГилО, due to large fluctuation contribution to conductivity the coherence, length, £l0) • .in bo .iv.il lable too. Finally, lining the «spreesion: ф • «• i о 5 «1 :1 * f* Т/Г. Flg.l Psgnetocalorlc effect for УВа3СиэОт_у <Тв=<12 К) - • ; for (BiPb)aSraCaaCu3Oy (Т =108.2 К) - * we calculate the heat capaslty jump at T=T„. Direct measure ment of the heat capacity for finding this value Is not so reliable sins electronic contribution to the HTSC heat capa slty Is not In excess of 1.5 per cent as compared to the lat tice one. Besides, In this case as well the effects of lnho- mogenelty and fluctuations- turn out to be large. The effective values of main hlgh-T= material parameters are listed In Table 1. Table 1 ^"aa . -i AS . -x AC -1 Hatertal T K 0e K ж 'mole dT H * T YBajCUaO,.,. 0.64 0.4 25 26 (BiPb) 3SraCaaCusOy 0.90 0.5 27 65 REFERENCES 1) A.M.Bykov, P.M.Mlkheenko. Ya.I.Yuzhelevskli,- In the book: XXVI All-Union Conf. on Low-Temp. Phys. Abstracts.Donetsk, 1990. v.I, p.90 (In russlan). 66 CALORIC PROPERTIES OF DENSE MODIFICATIONS OF BORON NITRIDE IN THE .300-1300 К TEMPERATURE INTERVAL V.L.Solozhenko' V.E.Lusternik* I.A.Holodov1 1 Institute for Superhard Materials of the Ukrainian SSR Academy of Sciences. Kiev, 252153, USSR г Institute for high temperatures of the USSR Academy of Sciences, Hoscon, 12J112, USSR The heat capacity of cubic boron nitride (cBN) single crystals Has measured in 160 points in high-temperature adiabatic calorimeter from 300 to 1100 K. Experimental values of hoat capacity narked by * are shown in the Fig. 60.0 The coefficients of Reshetnikov's equa tion which is very suitable not only*for approximation of expe rimental data, but for extrapolation of C°(T) vs T dependence both to high and low tempe rature intervals, were calculated by square feets method. 00 1000 1200 1400 Temperature, К The equation looking like C°(T),J/(Kmol) « 48.404- IT* /IT* • 9.706T + 60580.141)]' (1) is shown with a dashed curve in the Fig. A good agreement between experimen tal [1] (marked by *) and calculated according to equation (1) values of cBN heat capacity in 4-300 К sange is observed. The enthalpy of thatmostabilized wurtzite boron nitride [2] (wBN) was C7 ' measured in HT 1500 SETARAH high-temperature heat flux calorimeter from 400 to 1300 К in 12 points using inverse drop-calorimetry technique [3]. The mathematic treatment of experimental data was carried out by Shomate's method, considering the value of C°(29B.15 K) determined earlier [4]. If F(T)*A + B-T + C-Tr Shomate's function which'provides optiical approximation of experimental points .is used, the temperature dependence of wBN enthalpy in ЭО0-1300 К interval is described by equation H°(T)-H°(298.15 K).J/(K*ol) * 22.540T + 1.7023 10"*-Ta - 4.1053 10"*-Ts • + 1344627 T"1 - 12632.024 (2) Deviations between experimental and calculated values are less than 1.2 X. Equation for dependence С (T) vs T shown with a solid curve in Fig. NRS obtained by differentiation of equation (2). •On the base of experimental data and standard values of thermodynamic functions of cBN [1] and wBN [3] the values of enthalpy, heat capacity, entropy, and Gibbs' enorgy for dense modifications of boron"nitride in 300- 1300 К temperature interval were tabulated. References [1] V.L.Solozhenfco et al. Rtiss.J.Phys.Cbem., 61 (19Я7) 1480 [2] V.L.Solozhenko Reactivity of Solids, 7 (1989) 371 [3] V.L.Solozhenko et al. Suss.J Phys.Chem., 61 (1987) 412 [4] V.T.Gorbunov et al. Zh.Fiz.Khim.. 62 (1988) 18 (in Russian) ее THE FEATURES 03? TllEHLODYMAlilC PliOPEIiTlES 01' IOJLTILAYEKBD ALKALINE KAKK-EAhTli UIMOLIBbATKU * * * B.E. Anders, A. 3?eger , A. Orendacheva , P. atefanyi , A*I. Zvyagin Institute for Low Temperature Physics and Engineering, UkrSSR Acad. Sci., 47, Lenin Ave., ЗЮ164 Kharkov, USSK * Safarik University nam. i'ebr. vit. 9, 041ЬА Kosice, Czechoslovakia The investigated dimolibdates witli structural formula iiiE(liuoOi)2(bi = Cs, K, li = Dy, Gd) foriii a unique group of chain- layered structures with a variety of specific properties, which gradually change with the change of Id and K. The multilayered structure of these crystals leads to the anharnionism of the lat tice vibrations at low temperatures that in connection with the dynamic instability of the lattice may give rise to a number of structural phase transitions. Some of these transitions develop on the basis of the cooperative Jahn-'i'eller effect. The phase transition to a complex noncollinear magnetical ly ordered state with a strong anisotropic interaction is ob served at temperatures about 1 К or lower. This paper deals with low temperature peculiarities of the phonon spectrum connected with the low dimensionality of the crystal structure. The specific heat crystals was measured by the absolute adiabatic calorimetry method in the temperature range 0.35-13 K. hhombic crystals of CrK (IVioOj,)2 (К с Dy, Gd) are isostructural (space group iP^bat 1'oom temperature) while KDy (1UO0J.)2 (space group 3)W2h) 1B not isostructural to them, but may be considered as layered 2n-polytype ( n is the number of (Ly (ЫоОл^) layers) [.1]. The samples were grown by the flux method in the form of crystal plates. The phase transition to the magnetically ordered state is observed for CsGd (toO^k (TM = 0.45 Ю, CsDy (tuoOj,),, (TM * 1.3 K) and KDy (ЬоО^г (TM •= 1.1 K). Thermo dynamic parameters of the magnetic phase transitions are deter mined. For the evaluation of the heat capacity data the following procedure was used. The heat capacity is expressed as С в cL + 2 + См+С]ь. The term CM« b'£* represents the magnetic contribu tion at T 9 TM . According to the scheme of the electron energy levels of the magnetic ions, the Sliottky contribution to the heat capacity C^h was calculated. The analysis of calculated temperature dependence of lat tice heat capacity indicates that the terms characteristic of the structural 2C systems were found in the heat capacity of CsDy (KoO/y)» and CsGd (tnoO^)2 while the heat capacity of KDy (i;o0//)a has indications typical for structural 3D systems. It can be ex pected that in CsDy (Jwoty )a and CsGd (LoO*^ crystals the long wave part of the phonon spectrum would contain a quadratic dis persion law [,2]. References 1. A.V. Vinokurov, P.V. Klevtsov, Kristallografiya, 17 (1972) 127. 2. J.L.. Lifs)iits, Zh, Kksp. Teor. 1Чи. 22 0 9!>2j 471. 69 THERMODYNAMIC PROPERTIES AND PHASE EQUILIBRIA IN [ xCaF2+yS102+ 0-x-y)CaO} . A.I.Zaitsev, A.D.Litvina, B.M.Mogutnov Lab.of Thermodynamic Investigation's,I.P.Bardin Central Research Institute of Ferrous Metallurgy, 9/23 г3* Bauman Street, 107005 Moscow, USSR. The thermodynamic functions of {xCaF2+ySi02+(1-x-y)CaO} are required for analysis,computation and prediction of the che mical reactions that take place in processes of refining,desoxi- dation,alloying of steel and in welding. However,there are only fragmentary and highly contradictory data on the thermodynamic properties of {xCaF2+ySi02+(1-x-y) CaO] slags. In the present Investigation a Knudsen effusion technique combined with a mass-spectrometric analysis of evaporation pro ducts has been used to investigate the thermodynamic properties of { xCaFo+ySi02+(1-x-y) CaO} slags both in the liquid and solid states. Тле temperature range was 1400 to 1830 K. Composition va ried in the range 1 to 100 moles per cent of CaF2, 0 to 82 moles per cent of Si02, and 0 to 76 moles per cent of CaO.The measured pressures of the vapour components over the.slags made it possib le to calculate the formation thermodynamic functions of all the solid and liquid phases of the system. It is important to empha size that the calculations were carried out in different ways with the same results. The thermodynamic properties of melts as function of compo sition and temperature have been approximated with the help of the model based on the theory of associated solutions.Formation of the associated complexes CaO'SiO» and 2CaO*Si02 was supposed to take place in the liquid.solution. Polymerization of silica molecules resulting in the formation of the branches of any length and form was also taken into account. Compositions of the associated complexes chosen are in a good agreement with the cha racter of compositional dependences of structure-sensitive physi- cochemical properties of (xCaF2+ySi0o+(1-x-y) CaO} (l).The model suggested here has been found tB represent the thermodynamic fun ctions of the melts with precision no worse than experimental (1-2 per cent). To prove the reliability of the thermodynamic information acquired computations of a set of phase equilibria in { xCaF2+ +ySi02+(1-x-y) CaO} have been performed. The results of these calculations based on the thermodynamic functions only agree well with the phase diagram data available in the literature and ob tained here through physicochemical analysis in additional expe riments. 70 A NEW AFrHOACH TO THE THERMODYNAMICS OP THE SYSTEMS PORMED EY TIIE COMl-OUNDS WITH DII'FfiRSNT .ANIONS AND CATIONS. A.I.Zaitsev, B.I.l.Mogutnov, V.A.Litvinenko Lab. of Thermodynamic Investigations, I.P.Bardin Central Research Institute of Ferrous Metallurgy, 9/S3 2nd Bauman Street, 107005 Moscow, USSR. Thermodynamic functions of systems composed of compounds with different anions and cations including oxide systems are required for prediction ">f geological processes,for calculation and optimi- aation of chemicil processes in metallurgical,welding,ceramic and glass technologies. Though the systems of this kind are widely spread in the nature and are widely used in modern techniques the corresponding thermodynamic information is rather scarce and con tradictory. The experimental data are obtained mainly with indi rect methods and their theoretical interpretation is based on the ideas of perfect or regular (subregular) ionic solutions and on empirical approaches. This situation is caused by serious diffi culties that are met with in both experimental and theoretical studies of the systems. In the present work wide investigation of the thermodynamic properties of liquid oxide systems as well as systems involving oxides, fluorides and phosphides has been performed. The main file of the data was obtained by direct measurements of the component vapour pressures with the help of an effusion technique coupled with a mass-spec'trometric analysis of evaporation products or by a static method. The analysis of the results obtained together with data available in the literature permitted to conclude that the thermodynamic properties of complex oxide melts as well as that of systems composed of the compounds with different anions and cations may be approximated by the model based on the theory of associated solutions. For example,the thermodynamic properties of (xCaPo+yAljOj+d-x-y) CaO} (l) are well described if the asso ciated complexes CaO-AlgO, and 2CaO'Al20, are supposed to be for J med. In the сазе of (xCaFo + ySi02+(1-x-y) CaO} the formation of the complexes CaO-SiOo, ZCaO'SiOo and selfpolymerization of sili ca are taken into consideration. In both melts the association re actions are connected with difference in properties of cations. In the systems of another sort: {xCaF?+yCaO+(1-x-y) Ca^Pp} , {xCa +' +yCa,F2+(1-x-y) CaK2} , {xCa+yCaO + (1-x-y) Ca3P,} association re actions in mcltn are caused by anions interaction; For example,the thermodynamic properties of {xCa+yCa,P2+(1-x-y) CaF2}(l) and {xCra0-tyCnPo i (1-x-y) Ca,P„} (1) may be approximated if the asso ciates Ca,'-F,, Ca~PF are Supposed to be formed. Although the sys tems studied-Vire quite different in nature and properties the ther- modynpmic functions of their formation are well represented with the help of the same approach based on the supposition which is in accordance with the data on the melts structure. The results of computntiona o<" the pha?e equilibria in the systems under discus sion have proved that the description suggested is adequate. 71- THERMODYNAMIC PROPERTIES OF CRYSTAL HOLMIUM (II) CHLORIDE V.P. Goryushkin, A.I. Poshevneva Siberian Iron and Steel Institute, Novkuznetsk, USSR In the case of Holmium (II) Chloride a borderline stability situation is encountered СИ. As for the investigations of ther modynamic properties of HoCl? they have not been reported yet. Crystallographic data of HoCl- have been disorlbed by us earlier [21. HoClp has been formed by^ annealing stoichiometric mixture of HoCl, ^and Ho in sealed tantalum ampules at temperature of 780 К •'during 1000 hours. In present work the thermodynamic properties of HoCl~ have been investigated. The method of EMF with a solid eleotrolyt has been employed. The measurements of the ЕЮ? of the cell .- (Pt) SrtSr012H Ba012ll HoClglHo (Pt) + (1) ««4 —4 have been made in vacuum at a pressure 1.3*10 -4.0°10 ^ Pa in temperatures intrval of 518 - 633 K. In this case the cell reac tion is HoCl2 + Sr a Sr012 + Ho . (2) The obtained experimental data are given on Fig. The method of the least squares was used to obtain the line of the best fit due to the data points as an aquation linear in temperature. It is as follows: (92.7 + 3.2)»10~2 _ (9.0 + 5.6)»10~5.T, V. (3) E,V 0,88 0,86 500 520 540 560 580 600 620 640 T.K Thermodynamic characteristics of the cell reaction (2) (Tab le) and Holmium (II) Chloride were calculated by a second-law me thod using the reference and valued data on a heat capacity and thermoconstants Sr, SrClg, Ho, HoCl2> E, V T, К urG"(T), W tjfl'W, kJ arS°(T), J«K"1 578.40 0.87554 r-168,96 + 0.33 -178.96 + 6.23 -17.3 • Ю.8 298.15 -178.47 + 0.23 -16.2 + 10.8 The thermodynamic properties of Holmium (II) Chloride are: 1 д^"(298,15) - -655.9 ± 6'3 kJ.Mol" 5 Se(298.15) = 150.8 + 10.8 J«K~1.Mol~1. REFERBJNCES 1} D.Johnson, J.Chem.Soc. (A) 17 (1969) 2578. 2) V.Goryushkin, I.Astakhova, A.Posiievneva, S.Zalymova, Zn.Heor- gan.Khim, 34 (1989) 2469, Buss. 72 THERMODYNAMIC PROPERTIES OF IONS EMITTING FROM RbAg4Ig AND CuCl L.S.Kudin, A.M.Pogrebnoy, G.в.Burdukovskaya. K. S.Krasnov Dept.of Physics, Institute of Chemistry and Technology, Ivanovo, USSR. The compounds under investigation are well-known solid ionic conductors. A combination of the Knudaen effusion method with mass spectrometrlc detection has been used. The types of ions emitting from the salts in the temperature range Б00-800К have been established. The Richardson Daahman type equation has been applied for determining of work function 4» values of ions. The constants of lon-molecuiar equilibria for RbAg4l5 have been measured. The enthalpies of the reactions and the enthalpies of formations of ions on the basis of the second and the third laws have been calculated. The data obtained are given in the table. CuCl RbAg4l5 Ion p.ev Ion p,ev Ion AfHCOWkJ/moie Na+ 1,8*0,9 Rb+ 1.9*0.1 Rb2l+ 194*7 K> 2.1±0,05 Rb2I- 1.9*0.1 RbI2- -471*8 Rb* 1,8*0,3 Rb3I2* 3,3*0,9M Rb3I2* -67*15 Ca* 1,4*0,05 Rb2Agl2+ 2,2*0,2 Ag2I+ 963*10 Си* 1.8*0/4 Rb2Ag2I3+ 2,2*0.4 AgI2- -257*10 CuCl* 2,3*0,5 Ag+ 2.0*0,1— Ag3l2+ 926*15 CifiCl* 1,8*0,2 Ag2b 1,9*0.3— RbAgI* 539*10 cuaci2+ 2.2*0,4 I- 2,5*0.4 Ag2l3- (-325)—» Cu3Cl2+ 1.7±0,2 I- 4,8*2» Rb2AgI2* 200*15 Cu3Cl3^ 1,6±0,2 Agl2- 2.3*0.4 RbAg2I2+ (600) Cu4Cl3* 2,0*0,2 Rbl2- 3,3*0,3- RbAg3I3+ (650) Cu4Cl4-» 1,8±0,2 AgRb3I3+ (-6) Cu5Cl4+ 1,2*0,8 Rb2Ag2l3+ (230) Cu5Cl5+ 2.0*0,2 Rb3AgI3+ (-130) Cu6Cl5+ 1.3±0,3 CU8C16+ 2.0*0,2 Cu7Cl6+ 1,7*0,2 Cu7Cl7* 2,0*0.2 CU8C17+ 2,2*0,1 Notes: » - for individual Rbl; «m - for individual Agl; »m» - estimations are given in brackets. Along with the ions listed in the table C1-, CuCl3-, Cu8Cl8+. Cu9Cl8+ (for CuCl) and K+, Cs*. K2I+, KRbl*. F-, Cl- (for RbAg4I5) have been detected. 72 THE ENTHALPIES OP FORMATION OP GASEOUS HALID2SS OP TITANIUM. V.I.Tsirelnikov, M.I.Nikitin, L.V.Komissarova, E.M.Snlgire- va, N.M.Kosinova Faculty of Chemistry, Lenina Moscow Pedagogical University, Moscow, U3SH. The vaporisation of lower chlorides, bromides and iodides has been studied by effusion method with mass spectrometry regis tration of vapour species. The compositions of preparations were nearly TiXa and TiX-jC X - halogene ), grafite cell and electron bombardment ion source were used. The parent ions were determined from mass spectrum, variable because of vaporisation and indivi dual mass spectrum of tetrahalides, obtained by means of this in strument. At 800 - HOOK, when composition of condensed phase was nearly Tie ( activity of Ti is equal 1 ), partial pressures TiX^, TiX7 and X'iXa were measured and equilibrium constants К в of reac tions I table 1 } were calculated. To check an equilibria condi tion the К independence on partial pressures ( changed to 2 - 30 times at constant temperature ) was used. The thermodynamic func tion from [11, enthalpies of formation of tetrahalides C1t2] and reactions from table 1 were used to calculate а{НД.(Т1Хп} listed in table 2. T Table 1. The enthalpies of reactions in Ti - X sistems at 2У8К, n» low (kJ/mol>. CI Br 1/2 TiX, + 1/2 TiXi»l'iXs -15,7*2,9 1,8*1,0 0,8±0,5 1/4 Tit + 3/4 TiX^-TiXj 48,3t1i1 67,6+0,5 69,211,2 Table 2. The enthalpies of formation of gaseous titanium halides (kJ/mol). CI Br TiXi, -1551,4 -763,2 -550,2 -288,3 TiX3 -1076,7 -524,1 -345,1 -147,0 T1X2 -565,5 -253,6 -143,5 -7,3 T1X 26,7 124,5 (-39) (151) (207) (276) The enthalpies of formation titanium fluorides and TiCl were cal culated on base of dates [3]. The values for titanium monohalides were also estimated by means of relation S?(TiX{|;^De(TiX) THERMODYNAMIC INVESTIGATIONS OF Sc-Ou ALLOYS S.P.Raspopin, L.F.Yamshchikov, A.B.Shubin Physico-Technical Department, Urals Polytechnical Institute, Sverdlovsk, 620002, USSR In recent years more and more attention has been paid to the scandium alloye. At the same time, thermodynamic information about these systems is limited. The data available for Sc - Cu alloy* are sistematized in the paper of Subramanian et el . In this work the thermodynamic properties of scandium - cop per intermetallic compounds were investigated by the chronopoten- tiometrlc method . The electromotive force of cells of the type Sc-Cu(solid alloy)/ SeCl, + LiCl-KCl(eutectic)/ L+ScPb, has been measured over the temperature range 650-1040 K. The thermodynamic data for (Ii+Sc?b~)-electrode are known'• This permits calculation of the thermodynamic potentials of scan dium in Sc-Cu alloys. The values of the partial enthalpies and entropies of scandium in various regions of the phase diagram Sc-Cu are reported in the Table. Also partial molar Oibbs ener gies at 850 К (a middle of temperature range investigated) are given in the Table. Region AHSc, kJ/mol ASSc, J/mol-K AGSe(850K),kJ/uiol Cu+Cu.So -115.3 + 4.2 -46.0 д 5.0 -76.2 ± 0.4 Cu.Sc+CUgSo -81.5 + 4.5 -40.7 i 5.2 -46.9 +0.6 Cu2So+CuSc -43.5 +4.3 -10.7 * 5.1 -34.3 ±0.5 The data in the Table were utilized to calculate integral Gibbs energy of formation values for the phases Cu.Sc, CUgSc and CuSc( J/mol of atoms): AfG(Cu.Sc) « -23100 + 9.2 T;AfG(Cu2Sc) ш « -32800 + 14.5 T; AfG(CuSc) - -35500 + 13.5 T. The integral en thalpy data of our work are in excellent agreement with the valu es calculated with the semi-empirical model of Hiedema''. REFERENCES 1) P.R.Subramanian, D.E.Laughlin, D.J.Chakrabarty. Bull, of Alloy Phase Diagrams» 9(1988) 378. 2) V.A.Lebedev, V.I.Kober, L.F.Yaroehchikov. Thermochemistry of Alloys of Rare Earth Metals and Actinldes. Reference Book. Chelyabinsk! Metallurgy. 1989. THERMODYNAMICS OP MUbTICOMPONENT LIQUID-METAi SYSTEMS D.N.Kagan D.N., G.A.Krechetova, E.E.Shpilrain Institute of High Temperatures USSR Academy of Sciences IVTAN, Izhorekaya, 13/19, Moscow, 127412, USSR . The method of' experimental investigation of thermody namic functions of multicomponent liquid-metal systems on the tasir; of alkali- and alkali-earth metals is proposed and rea- ijzed. Sunh systems, reserving all the advantages of pure oom- Fonsnfcs, acquire additional merits: a) maximum broad dia- ..ason of working temperatures (from criogenic up to criti cal ), being' both high-temperature- and low-temperature вузterns simultaneously; b) possibility of regulation of i.ermo- and electrophysical properties. The method is based on calculation of -haraoterietical functions (potentials), i.e. Gibbs energy of formation of liquid alloyti (AG) or thermodynamic! activity (a,) in broad area of temperatures and concentra tion? by integration of differential equations of chemical thermodynamics [u in а./д(1/Т))п =4Я./Я ; [d(&G/T)/d(1/T)] =Atf, with experimental determination of: 1) underintegra.l functions [partial and integral enthalpies of formation in all area of named parameters of state tH--f(x.,T), LH=f(x,,T)] and 2) boundary conditions [concentration dependences of Mciivities or Qibbs energies at one temperature - reference temperature T^QOK a-=f{x^,f^), i.G^f(xi,T1)). ''he advantages of this algorythm which can be provided with reliable input experimental data and permite to obtain inwardly-agreed thermodynamic description of studied systems are demonstrated. For solution of both experimental tasks two groups of installations was constructed. The first group includes a ooipplex of caiorimetric apparatus with level of sensitivity permitting to determine of excessive thermodynamic functions of liquid-metal systems. The second group is based on determining of activities of components depending on partial pressure of saturated vapour obtained by measurement of intensivety of their atomic flows with help of effusion method •i".it»? eJ"ctron-beam bombardment. The data for all of named thermodynamic functions and i.:.eir doviatives in diapason Q^r.^1, THau.idus^'^15 -o.-i.~ontrat.ion correlation function Scc(0) physical interpreta tion of results is presented. 76 THERMAL DISSOCIATION OF YBa2Cu3<}y. A.N.Yankln, I.N.Dubrovlna, G.D.Deryabina, . Yu.V.Golikov, V.F.Balaklrev Institute of Metallurgy, Ural Division of the USSR Academy of Soienoes, Sverdlovsk, USSR. A study is made of the phase equilibria upon thermal disso- olatlon of the tetragonal YBagCu-Oy-phase In the temperature range 730-900*C. The etatle method using a vacuum circulation assembly with an oxygen pickup made of eolld electrolyte la followed by an X-ray phase analysis of the quenched solid phases. The statio me thod la also used to determine the oxygen oontent In the Initial phase and at the low-oxygen boundary of its homogeneity range. The value у = 6.00+0.06 corresponds to the homogeneity range low-oxygen boundary over the whole range of temperatures used in the study. The main phase-forming reactions upon sucoesslve remo val of oxygen from the phase under study are the followings YBa2Cu30g - I/2Y2BaCu05 + 5/4BaCUg02 + IABaO +3/802, (I) Y2BaCu05 - I/2BaCu202 + I/2Ba0 + Yg03 + IA02, (2) BaCu202 - BaO + 2Cu + I/20g. (3) Temperature dependences of oxygen pressure for the equilib ria of reaotions (I) - (3) were determined. They are described by the following equations, respectively: lg P0 (Pa)j - -I52I0/T + 15.53 ± 0.II, (4) lg P0 (Pa)2 - -24890/T + 20.46 + 0.20, (5) lg PQ (Pa)3 - -20I80/T + 13.38 + 0.II. (6) Variations of thermodynamic funotlons were also estimated . for these reactions. INFLUENCE OF GLASSFORMING OXIDES ON THE Li О PARTIAL PROPERTIES 2 IN BINARY MELTS. E.L.Kozhina, B.A.Shakhmatkin and M.M.Shultz. Institute of Silicate Chemistry USSR Academie of Science Leningrad The EMF study of lithiumgermanate' melts containing 0-30 mol.X Li40 was carry out in order to find the effect of the glassformlng oxide nature on Li40 partial thermodynamic properties. The tempera ture' range of the experiment was 1073-1423 K. A 0.20 LijO-0. 14 А1г Оу 0.66 SiO| glass was used as a reference system. Earlier we had per formed a study of LijO - SiO« system С13 and LijO - B;0y system С23 melts in the same temperature range. The Li^O chemical potential, partial entropy and partial enthalpy were calculated from the experi mental temperature dependences of the EMF values. Due to the absence in the literature on the subject of high-temperature thermodynamic data for any composition of the system the Lia0 partial function* ob tained were refered to those of pure lithium oxide, data in С13 be ing used for this normalisation. The accuracy of measurement was grea ter than ±0.4 kcal/mol for AftitigO I ±1*2 cal/K mol for д Б^де (fig. 1,2). The properties of lithiumgermanate melts have some analogy both with llthiumsilicate and lithiumborate melts which is due to the structural features of the system. As for the above acid-alkaline type systems the behaviour of the LijO - SeOj melts displays a great negative derivation from the ideal one. This is due to the formation of the compounds Li^O- 7GeO^ and Li^OGeOj in this particular concen tration region. Alkaline metagermanates are isostructural with meta- sillcates, but in the low-alkaline region the structure of germanate melts is substantially different. This results from the fact that the addition of alkaline oxides to Ве0г causes the change of Qe coordina tion number fron 4 to 6 C33. The maximal content of the octahedron- coordinated Ge is 25-28% in crystalline samples and is somewhat lower in glasses. Such groupings were found in the 0-25 mol.X composition range of Li^O, their maximal content being at 12.57. (Ii7 composition). The Se coordination number changing from 4 to 6 affects the properties of lithium germanate melts in the same way, as the change of c.n. from 3 to 4 in the lithiumborate system. A minimum is formed on the о Зцг0 »f Fig.1.Chemical potential of Li 0 aa a 'Function of X at 1423 K. 1 - Li 0 - 810 2 - Li 0 - SaO 3 - Li 0 - 8 О Fig.2. Partial entropy of Li 0 aa a function of X at 1423 K. 1 - Li 0 - 8i0 2 - Li 0 - BeO 3 - Li о - В О REFERENCE 1.Н.Н.Нульи, Е.Л.Кояина, Б.А.Шахматкин , Вести.ЛГУ,сер.4, 1(1986) SS. 2.Б.А.Шакматкиы, М.М.Нульц , еиа.и хим.стекла, 8 (1982) 270. S.S.Bakka, K.Kaniiya, J.Non-Cryat.Bol. 49 (1982) 103. 4.Л.ПОЛИНГ. Общая химия. Л.1970, 419 с. 79 THERMOCHEMISTRY OF MIXED HALOGENIDES AND OXYHALOGENIDES FROM ION-ION AND ION-MOLECULAR EQUILIBRIA. M.V.Korobov. J.V.Pervova. A.A.Mavrin, L.N.Sidorov. Dept. of Chemistry,- Moscow State University, Leninskie Богу, 119B99 Moscow, USSR. In recent decade Knudsen cell mass soectromt- -y with thermal ionization (KCMSTI) has become an important rce of gas-phase Ihermochemical data for high .temnerature species. In the present work this technique was applied toward the study of halogen exchange or halogen-oxygen exchange eauilibria. For example, the enthalpies of reactions AlF„Cl»-„ + F = AlF„Cl3ln + CI <1> (n=0.-.3) P0a~+ 2F = PO„Fa% О <2> can be found. From the thermochemical data derived from our eauilibria measurement the substitution effects on the bond dissociation enthalpies, electron affinity, enthalpies of forma tion of mixed particles have been followed. Such information is of a great value for estimation of thermochemistry for unstudied soecies. To derive Bibbs energies and enthalpies for reactions(l) the ion-ion exchange equilibria of the type A1F„CU_„ + NF~= AlF^Cl»-,, + MC1~<3> where studied, where NF and MCI are species far which the thermochemistry of reaction NF~+ CI = Mcf + F is accurately known. Negative ion-KCMSTI seems to be a powerful exchange eauilibrium techniques. In conventional KCMS of neutral species the electron impact fragmentation of the mixed molecules prevents such type of measurements from being successfully per formed. The following systems were under study: I) Al-F-Cl-Br-I. The substitution effect on the thermochemistry of AlHal*-, AlaHal7-, KzAlHale~ where examined (Hal - halogen). 2> P-O-F. The binding enthalpies of flouride ion to PFs,POF3,P02F •ч'.еге followed. ':> Fe-Cl-F, Cr-Cl-F. Electron affinities and binding enthalpies of iron and chromium fluorides and chlorides were compared. 60 THE RELIABILITY AND PREDICTION OF HIGH TEMPERATURE BEHAVIOUR OF MULTICOblPONENT OXIDE SYSTEM V.L. Stolyarova, G.G. Ivanov, I. Yu. Archakov Institute of Silicate Chemistry of the USSR Academy of Sciences, ul. Odoevskogo 24, korp. 2, 199155, Leningrad, USSR The data on the vapour composition, the partial vapour pre ssures, the component activities and chemical potentials aa well as the Gibbs energies are summarized for ten samples of the mul- ticomponent oxide systems containing SiO?, B~0,, Al50,, CaO, FeO, 5 MgO, Na?0, K~0, Li20. These results were obtained By the high temperature Knudsen effusion mass spectrometric method at 1000 - - 2000 K. The -acid-base concept was used for the prediction of the high temperature behaviour of these multicomponent systems. It was shown that the dissociation, polymerization, association in the gas phase may be predicted in these systems when we consider the oxygen vapour pressure as a measure of the acidity of the oxide system. This approach explains the existence of the mixed molecu les such as NaK ( B0~ )_ in the gas phase. The reliability^of the thermodynamic properties for the cor responding binary systems (1 ) as a part of multicomponent systems studyed were shown based on the following main points. There were the correlations between the experimental results ob tained by the mass spectrometric, e.m.f., transpiration, gas phase exchange methods and the comparisons between the phase diagramms and the thermodynamic equations of the phase stability. It allowed to revise the available data and to apply them as the base for the calculations of the component activity coefficients and the Gibbs energies in the multicomponent systems using the Kohler ( 2 ) and the Wilson ( 3 ) methods. The parameters of the Wilson equation were improved according to the consideration of their concentration dependences from the composition of the condensed phase. The experimental values of the thermodynamic functions of the multicomponent systems obtained by high temperature mass spec trometry and by the high temperature solution calorimetry were compared with those calculated from the data of the thermodynamic values for the binary systems using the semiempii-ical Kohler and Wilson methods. It was shown that these methods may be utilized for a qualitative estimation of the Gibbs energies of multicompo nent systems using the data for the corresponding binary systems. REFERENCES 1) G.A. Semenov, V.L. Stolyarova, Mass spectrometric study of the vaporization of oxide systems, Leningrad, Nauka, 199o, 300. 2) F. Kohler, Mh. Chem. 91 < 1960 ) 738 . 5) 'G. M. Wilson, C.H. Deol, Ind. Eng. Chem. Fund. 1 ( 1962 ) 20. fcl THERMODYNAMIC PROPERTIES OF LANTHAHOID (III) CHLORIDES D.M.Laptev, T.V.Kiseleva, V.V.Vasiljev, D.I.Oschepkov Siberian Iron and Steel Institute, Novokuznesk, USSR The measurements of the W of the following cells -(Pt) Ln|LnCl,ll ВаС12Я MgGlgl Mg (Pt)+, 2Ln + 3M6C12 = 2LnCl? +3%, where Ln is the La, Ce, Pr, Gd, were made in Vacuum at a pressu- re of 10— 4.. . 10— -T? ч a and in the temperature range from 500 to 600 K. The obtained data were transformed in the function RlnK(T), where K(T) is equilibrium constant of the cell reacti on.They were treated by the method of least-squares. The values of л£Н°(Тв), S°(T„) and C°(T0), where T0=298,15 K, calculated from experimental data by a second-law and third-law methods of thermodynamics using literary data [1,2]and reference book data [3] • This values are given in Table with number of experimen tal points n and uncertainty on the confidence level of 0,95. The uncertainty of standard entropies are define more pre cisely by a third-law method. ' Sub Third law Second law 0 в stance д£н (т0), Д£Н (То), S»(T0), C|(T0), n kJ mol"1 kJ mol"1 J K"1mol"1 J 1Г1то1~1 LaCl7 -1062.2П.1 -106B.9+18.2 12b.6+1.3 9^.29' 21 CeCl. -1029.0±1»3 -1028.7+29.6 150,211.a 98.57 • 24 PrClj -1036.1±1.1 -1038.1+7.9 149.5±1.1 99.04 41 GdCl, -1018.7+1.8 -Ю17.214.5 137.0+1.7 97.84 Я REFERENCES 1) l.A.Sommers and E.F.Westrum, J.Chem.Therm.,8(1976), 1115. 2) I.A.Sommers and E.F.Westrum, J.Chem.Therm.,9(1977), 1. 3) I.Barin, O.Knacke, O.Kubaschewski, Thermochemical properties of inorganic substances Supplement,-Duaseldorf: Springerver- lag Berlin-fleidelberg-New York Stahleisen, (1977>,-861. 82 MASS SPECTROMETRY INVESTIGATIONS OF Fe, Co AND Ni IODIDES Ryzhov M.?u., Nasretdinov A.A. Thermocenter , Institute for High Temperatures, Academy of Sciences, Moscow, USSR The iodides of Fe, Co, and Ni are of interest from the point of view of nuclear reactor safety. The available thermodynamic data concerning gaseous mono- and diiodides of this metals ( are incomplete and unreliable. The .investigation was performed using a quadrupole mass spectrometer with double Knudsen cell. Following atoms and molecules was detected in gaseous phase at 1550 K: Fe, Co, Ni, Pb, Pel, Col, Nil, Pel., Coi_, Nil-. Investigated reactions and their 3rd-law enthalpies calculated with the aid of thermodynamic functions from IVTANTHERMO data bank are given in table 1. Table 1. Reactions investigated -1 N Reaction ArH°(0) kJ mol 1 Fe+Nil=FeI+Ni 45. 9 +8 2 Co+NiI=CoI+Ni IS.4 +8 3 Pe+NiI2=PeI2+Ni -10.8+18 4 Fe+Col2=Pel2+Co -6. 3 +18 5 Fe+FeI2=2FeI 74. 5 +13 . To calculate enthalpies of formation and atomization energies of iodides the value AfH(Fel2,r, 0)-78. 8+12 kJ based r>n [1] and [2] wavalues usings excep. Tht e A_H°(Nil,g,0results.of )calculation and Do(Nils )ar were egive determinen in tabld e fo2r. Althle first time. Table 2 Enthalpies of formation and atomization energies of iodides -1 N Molecule AfH°(0) kJ mol Do kJ mol~ 1 Fel 283.1+ 7 236.9+7 2 Col 263.7+ 8 267.4+8 3 Nil 250.4+ 8 282.8+8 4 CoI2 96.2+ 15 542.1+15 5 Nil2 102.8+ 15 537.5+15 REFERENCES l.M.Grade, И. Rosinger Ber.Bunsenges .Phys. Chen. 1984, V.88, p.767-776. dokimova. Khlm., 1990 2.M.E. Efimov, V.P. Evi Zh. Ph. .«J, p.242. ег ION-MOLECULE EQUILIBRIA IN THE SYSTEM K2C03~K2S04. STABILITY OF CO~ and KCO~ IONS. I.V.Sidorova, L.S.Kudin* and L.N.Gorokhev Thermocenter, Institute for High Temperatures, Academy of Sciences, Moscow USSR tDept of Physics, Institute of Chemistry and Technology, Ivanovo, USSR. со" ion was found to play a significant role in the ionosphe re processes, which resulted in a set of CO3 stability investiga tions. Photodissociation spectroscopy and collisional induced dis sociation technique were used to determine the value of DQ(CO- O~) through the thresholds of appropriate processes. In flowing afterglow study the 'forward and reverse reaction rates were measured to calculate the bond dissociation energy. Corres ponding references are summarized by Huaton et al [11 and Snod- grass et al [2 J. In present study the ion-molecule equilibria technique was used for the first time to obtain the bond dissociation energy D°(C02-o"). This technique consists in measuring the equilibrium constants of. reactions,. including the ions ef interest, the ther- mochemical 'nformation about the rest being available. Ions generated in Knudsen cell by thermal ionization were ex tracted, colligated and Bass analyzed. The ions KjS04, K,CO,,K , KSOT, KCO~, S0~,SO2,SO~,Co", 0~, 0~ were detected while investi gating the system K.CO.-K-SO. (7 mol %). The, 4fH°(CO~, g, 0) was then determined using the enthalpy of reaction KJCOJ + SO~ = K3S0* + CO~ . The third law data treatment was made. Two values of D°(CO,-o") were obtained: 1) > 182 kj/mole (1.9 ev), 2) < 231 kJ/mole (2.4 eV). The second value was deter mined at the end of the experiment, when CO" intensity was lower than the detector sensitivity. Thus D"(CO -0 ) = 2.15+0.25 eV was accepted. The data obtained is in agreement with 2.27 eV accepted by Hunton et al [1] and Snodgrass et al [2]. Д£Н(КС0~, g, 0) = -«to ±20 kJ/mole was determined from the enthalpy of reaction: KC KJCOJ + KSO~ - K3S°4 + °3 • REFERENCES 1. D.E. Hunton, M. Nofmann, T.G. Lindane** and A.W. Castleman, Jr., J. Che». Phys. v. 82, p. 134, 1985. • 2. J.T. Snodgrass, CM. Roehl, P.A.M. van Koppen, W.E. Palke, and M.T. Bowers, J. Chem. Phys. v.92, p. 5935, 1990. 84 HASS SPECTROMETRY STUDY OF THE GASEOUS CESIUM TELLURIDES. L.N.Gorokhov, M.Yu.Ryzhov, Yu.S Khodeyev, A.M.Emelyanov and A.A. Nasretdinov Thermocenter .Institute for High Temperatures, Academy of Sciences, Moscow, USSR Cesium tellurides . are of interest because cesium and tellurium are the fission products and in the case of an accident of nuclear reactor they are able to react and can be transported from the active zone not only as cs and Те, but also in form Cs-Te compounds.Available thermodynamic data concerning Cs.Te(cr) and its evaporation are incomplete end seem to be contradictory Two samples were investigated: 1) with the excess of tellu rium over stoichiometric composition of Cs.Te ( the investigation was perforined with the use of quadrupole mass spectrometer MS 7301), 2) with the excess of cesium ( the investigation was per formed with the use of magnetic mass spectrometer MS 1301). The following ions were detected in mass spectra at, 1000 C£ for the sample with excess of Те - cs , Те , Те, , CsTe , CsTe2 ; for the sample wifcii excess of cesium - Cs , Те , Те. , CsTe , Cs.Te , + ' Cs2Te2 . The determination of the molecular precursors of ions was carried out by the measurements of appearance potentials from the ionization efficiency curves, i.e. relationships between ion cur rent and the ionization voltage. The molecule Te_ with well-known ionization potential 8.29+0.03 eV was chosen as a standard. Low appearance potentials were determined for all Cs Te_ ions. This fact indicates the formation of these ions from the molecules of the same composition. For the determination of the enthalpies of formation and ato- mizations energies of cesium tellurides gas phase reactions bet ween Cs, Те, Те. and molecules Cs те were investigated. For the calculation of the equilibrium constants all ion currents were measured with equal excess (3 eV) of electron energies over thre shold. Table 1 shows the ionization potentials and the typical mass spectra so obtained. Table' 1 Mass spectra o£ vapors over Cs-Te system (1 - The sample with the excess of tellurium, quadrupole mass spectrometer, T = 980 K, 2 - the sample with the excess of the cesium, magnetic mass spectrometer, T= 1036 K) - + - + + + Ion Cs те Te2 CsTe Cs,Te CsTe2 Cs2Te2 IP cV 3.9 9.0 8.3 6.1 4.5 5.9 5.0 Sample 1 0.38 3.2 100 0.29 - 0.48 - Sample 2 100 0.1 0.02 1 0.4 - 0.6 ED Reactions investigated and their 3rd-law enthalpies calcula ted using thermodynamic functions from IVTANTHERMO data bank, to gether with evaluated total uncertainty are given in Table 2. The enthalpies of formation and atomization energies of cesium tellu- rides are given in Table 3. Table 2 Reactions investigated N Reaction Instru-. т, к Number ЛгН°(0) ment of points kJ mol"1 1 Cs+Te =CsTe+Te Quadr. 932-1151 29 64.5 + 7 la Сь+Те =CsTe+Te Magn. 1023-1129 '8 59.1 + 7 2 2Te +Cs=2Te+CsTe_ Cuadr. 980-1090 11 65.1 + 12 3 Cs2Te=2Cs+Te Magn. 1023-1129 В 403.0 + 12 4 CsTe=Cs+Te Magn. 1023-1129 8 196.4 + 7 5 Cs Те =2CsTe Magn. 1023-1129 8 293.6 + 16 Table 3 Enthalpies of formation and atonization energies of the cesium tellurides N Molecule AfH°(0) Do kJ mol"1 kJ mol"1 1 CsTe 98.6+7 188.8+7 (1) 93.2+7 194.2+7 (Ia) 91.6+7 196.4+7 (4) av.94.2+7 av. 193.1+7 2 Cs2Te -37.6+12 403.0+12 (3) 3 csTe2 55.3+12 441.5+12 (2) 4 cs2Te2 -105.T+16 679.9+16 (5) ьь THERMODYNAMICS OF ELECTROCHEMICAL LITHIUM INSERTION INTO VANADIUM PENTOXIDE. V.I.Gavriluk, V.N.Plachotnik Sept. of Chemistry, Institute of Transport Engineerea, Dniepropetrovsk, USSR. The thermodynamic study of electrochemical lithium inser tion into vanadium oxides is of interest in connection with its possible application in rechargeable lithium cells /1/. These materials have a so-called open structure with rather large ca vities in which lithium ions can be reversible inserted from organic electrolytes at ambient temperature,forming oxide bron zes Li VpOr. But the cyclic behaviour of the vanadium oxides is largely governed by the microstructure of the host lattice. In the present paper we report the resulte of tuermodyna- mic and ion-transport investigations of crystalline (o) and Tne tlle;rm0(i namic amorphous (a) Lix^2°5* y data were provided by e.m.f. measurements method in 298-32? К temperature range and kinetic data - by relaxation techniques. The sample microstruc- ture was investigated by X-ray difraction and IR-spectroscopy. The experimental composition dependences of the partial molar free energy (дйц), enthalpy (&Язд) and entropy С&Взд) of v are in lithium in Lix o°5 agreement with the structure changes of the oxide bronze during lithium incorporation* The changes of the дЕт-; 1 corresponding to insertion-deinsertion processes for a-LixV20c was less than for the crystalline one,that is consis tent with the superiour reversibility of the a-V2Ogcompare with the c-oxide. From the dependence of the bTLAx) it may be concluded that ordering processos take place in bi V^Oc. To explain thermodynamic data changes we proposed the mo del for lithium insertion, in which assuming that lithium ions occupied sites with two different energies (aE=21,5 kJ-mol ) for the c-LixV205 ода with wide energy distribution for the a- oxldes. Electrostatic interaction between lithium ions leads to its ordering in oxide framework.The results of calculations ba sed on this model is in a good agreement whith thermodynamic data. REFERENCE 1) Yu.Tretyakov, A.Popov, Tu.Metlin. Solid State Ionics. 17 0986) 265. Ь7 DETERMINATION OF SATURATED VAPOR COMPOSITION FOR BINARY SYSTEMS AT ELEVATED PRESSURES ON P-X DATA N.L.Yarya-Agaev, V.C.Matvienko Dept.of Phisical Chemistry, Donetsk Polytecknlc Institute, Donetsk 340000, USSR The present report is conserned with the development of a strict thermodynamic method to calculate vapor composition in a binary sys tem containing vapor end liquid phases on the pressure and the satu rated liquid-phase composition data. The vapor phase described with the second virial coefficient equation of state is supposed to be presented with monomer molecules of components only which do not in teract chest illy. The developed equation connecting the vapor phase cempositon with that of the saturated liquid is: Hi. IP »чЬР^ (HT + »P)« \ ЫЬ/Р.Т J qK where y, ,y, ,x, and хя - respectively mole fractions of the first and the second components in the vapor and the liquid phases; P,T - equilibrium pressure and temperature; В - the second virial coefficient for the binary vapor phase. It la determined according to the relationship: 1 в = B,|3f* гв^у, rt* ifeA • •• (2) Bnand Bg^- the second virial coefficients for the first and the sec-, ond components respectively; В,г- the cross coefficient. In practical application of the equation (1) the integration la substituted with summation on finite increment in y. If the initial point for summation is the pure component 1 the equation (1) becomes Indeterminate. Evaluation of the indeterminate form produces the fol lowing relationship: W^-HVT^HUU-WU (3) № The latter equation aakes it possible to calculate the first value of у , when moving from the pure component 1 with a fixed step in x. Further calculation can de done according to the equation (1). The aethood discribed above has been used to ca_~ulate the equi librium vapor composition on P-x data determined experimentally in ethane-pentane systea at 4.4 С /1/ and in propane-ethane system at 10.0 С /2/. The second virial coefficient valus for the pure compo nents were taken from /3/. The results of the calculation show satisfactory agreement with the experimental data. For instance! the deviation in mole fraction of ethane in the vapor phase for the ethane-pentane system does not exeed 0.007. The approach descibed can be used not only to calculate equilib rium vapor composition on experimentally determined parameters for the liquid phase,but also to check the thermodynamic agreement of the vapor-liquid equilibrium data in binary system at elevated pres sures when association and chemical interaction in the vapor phase are absent. It is applicable to deteraininng new molecular forms if any of them are present in the vapor phase. Literature cited. 1.Reamer H.H.,Sage B.H.,Lacey W.N. J.Chea.Eng.Data,1960,5,N1,p.44 2. Matechke D.E..Thodos G. J.Chen.Eng.Data, 1962,7,N2.p.232. 3. Коган В.Б. Гетерогенные равновесия. Л.: Химия, 1968, 432 с. SATURATED VAPOUR PREt;bUKE AND 'JUBLIllATION ENTHALPY OF GERMANIUM V.I.Severin, A.V.Tseplyaeva, ?ч.Е.Khandamirova, Yu.A.Priselfcov, N.A.Chernova, I.V.Golubtsov Dept. of Chemistry, Moscow State University, USSR The literature data on sublimation enthalpy of germanium are in rafe contradiction with the values that calculated from the dissociation energy GeS and the enthalpy of formation and sublimation GeS . We have measured the vapour pressure of ger manium over wide temperature interval. The determination of vapour pressure of germanium has been made by means of an integral vatiant of Knudsen method in oilless -6 -7 vacuum 10 10 Pa. The effusion cell and the diaphragm were made of graphite MPG-6 with closed pores and were degassed in vacuum. Two samples of germanium have been used, namely mono- crystalline 99,99$ pure and polycrystalline of pure 99,999#. To test if equilibrium in the Knudsen cell was established the experiments were carried out with the germanium samples of va rious areas of evaporating surface, under the same effusion orifice. The statistical treatment revealed the statistical equivalence of the obtained results for the vapour pressure of solid germanium. Similarly statistical equivalence was for data on vapour pressure of loquid germanium with the results which had been obrained by ys earlier. The obtained results can be written as the equations: 1 lgPsol»(12,31*0,35)-(19210i420)T" <1134-1206 K) lePliq*(t0,83±0.l6)-(17410±230)T-1(1213-l647 K) {absolute errors are given by confidence limits 0,95). All stated above сHow us to recommend the value for sublima tion entha" >y germanium. 1 AeH°(Ge, cr, 29И.15 K) - 368,0*1,0 kJ-mol" (into account errors of thermodynamic functions). 90 SATURATED VAPOUR PRESSURE OF NICKEL V.I.Severin, A.V.Tseplyaeva, N.E.Khandamirova, Yu.A.Friselkov, N.A.Chernova, I.V.Golubtsov, V.B.Luk'Janov Dept.of Chemistry, Moscow State University, USSR The investigation was neccessitated by the absence of unequivo cal information on the vapour pressure and enthalpy sublimation of nickel in literature. We have measured the vapour pressure of nickel over wide temperature interval. The determination of nickel vapour pressure has been made by an integral variant of Knudeen effusion method in oilless vacuum —6 —7 10 -10 Pa. The effusion cell was made of alundum and was degassed in vacuum preliminarily. The samples of nickel of the mark PNC-I and NS.SP. have been used as well as that of with radioisotope nickel-63. To test if equilibrium in the Knudsen cell was establised the experiments were carried out with the samples nickel of vari ous areas of a evaporatinq surface (powder, pieces, remelting powder, liquid) under the same effusion orifice. The statisti- 'cal treatment revealed the statistical equivalence of the present results of the solid nickel vapour pressure, which were obtained in overall experimental series independently of the area and state of surface. The obtained results can be written as the equationst 1 lgPeol/Pa/=(12,27±0,33)-(21530±540)T~ <1522-l697 K) and 1 lgPlig/Pa/-(11,68±1,01}-(206OO±ia00)T" (1741-1793 K) (The corresponding absolute errors are given by confidence limits 0,95).All stated above allows usto recommend the value for enthalpy sublimation nickel at 298,15 К д„но/Hi, cr., 298,15 К/ - 424,7*2 kJ-mol-1 91 MEASUREMENT OF THE SPECIFIC HEAT OF Bi.Ge-O^g AND Bi4Ti3012 SINGLE CRYSTALS (50-1200°C) G.S.Suleimenova, V.M.Skorikov Kurnakov Institute of General and Inorganic Chemistry, the USSR Academy of Sciences, Moscow, USSR The interest in bismuth containing oxide compounds has lately increased for applications based upon their optical,photo- conductive, superconductive and other electrophysical properties. In the present paper the results of the specific heat mea surements of Bi4Ge-01;, and Bi.Ti^019 single crystals by DSC calo- rimetry are given.J ЛА ч J лс A Netzsch high-temperature DSC 404 equipped with a platinum furnace and a Рг/Rh sample holder was used for measurements. The experiments were conducted at heating rate 20°C min from 50 to 1200°C. Temperature control and data acquisition of DSC 404 were provided by Netzsch programmer 413, controller 413 and computer system with peripheral units* The specific heat study allows to obtain evidence of struc tural modifications in single crystals. For ieomorphous crystals Bii90e0„n and Bi^TiO™ (Bi20,:M0a «6:1) the epecific heat va u lues ?.ave been already obtalned[1'j. In case the mole ratio Bi?0,: M0„ is changed to 2t3, the compounds Bi.Ge,012 and Bi.Ti,0^2 ire formed with different types of crystal Stractfiro, correspondingly, Bi.Ge,Oi2-cubic, with euletyne *ype structure, manifesting intense scintillation properties, and Bi.Ti,012-ferroelectric, with tetra gonal layer cryital lattice including'perovskite type layers. The resultэ of the specific heat of Bi4Ge401p were approxi mated by the equi "ions , n r> fn •» * i Cp(iO,0030)-0,1857+5,37-lO^T-S, 19 O0_VTz+1,85 •KT^T^J.g'VK"1) The heat capacity values of Bi.Ge,01? were preliminarily es timated as additive in relation to the Heat capacity values of Bi12Ge0„o[l] and GeO„. Bi]pGe02o referred to,was believed to have predominant lattice Contribution in the heat capacity. , . 1 Cp (Bi.0e,012) - l/3Cp(Bi120e02Q) + 8/3Cp(Ge0a) (J mole" -K" ) Experimental and estimates values agreeS well. The epecific heat curve of Bi.Ti_012 is typical for ferro- electrics. The thermal histeresis,associated with structural re arrangements during the transition from the spontaneously pola rized phase to the non-polarized one, occurs. The specific heat of polarized phase was approximated by equation: ._ , , , Cp(2o,0042>0,202+6,5-10 ~3 T-8,4 .10~7Tz+4,5 10~'°T-* (J.gVK"'). Using the shape of heat capacity curve of Bi.Ge,Oi„ for in terpolation of "normal" Cp curve of Bi/Ti.,012, the^heaVof tran sition from the polarized phase to non*Doxarfzed one was estima ted with the result *He«10,9-0,IkJ-raole '. Heating of crystal samples higher th«n Curie point corres ponding to 670°C, makes the abeorbtion of heat for structural .rearrangements possible. The total entropy change for the transition region was found to be 11,62 J mole- K~ . The entropy change may be associa ted with an order-disorder transition. REFERENCES 1) G.S.Suleimenova, V.M.Skorikov, Thormochim.Acta - in press. COMPUTER ANALYSIS OF THERMOCKEMICAL DATA OF ORGANIC COMPOUNDS J.B. Pedlev and A.M. Welsby School of Chemistry, Leeds University, Leeds LS2 9JT. During the last few years the rate of production of reliable thermochemical data for organic compounds has decreased considerably and the need for accurate methods of prediction has risen correspondingly. To help satisfy this requirement a computer data base has been set up which now contains values for standard enthalpies of formation, entropies and heat capacities at 298.15K for solid, liquid and gaseous states of approximately 3000 organic compounds of the elements C,H,0,N.. S and halogens. A new theoretical model has been developed for machine calculation of thermochemical properties which fits most experimental values of standard enthalpies of formation of liquid and gaseous compounds to within experimental uncertainty; the procedure automatically includes corrections for steric interactions, ring strain and conjugative effects. Its application to other properties and to data for the solid stare is also being considered. The chief advantages of the new method over its predecessors are its sound physical/theoretical basis, and the completeness of the set of p.-.rameters derived by theoretical interpretation of trends in values of parameters fitted to reliable experimental data. Two types of program have been developed. The first is used to retrieve data for compounds having in common structural features such as functional groups and various types of ring system. The user is thus able to compare and contrast experimental data for various families of compounds and be provided with details of the literature from which these data were extracted. The second program requires as input only the structure of the compound which may be entered in various ways to yield predicted values of thermochemical properties. The two programs may be used togetner to display differences between experimental and calculated values for families of compounds to reveal more subtle effects such as long ranqe interactions, hydrogen bonding etc: which may not be completely allowed for by the model. The work forms part of a cooperative scheme on computerization of physical properties of organic ccmpounas associated with personnel at the Thermodynamics Research Centre of Texas A&M University and tha National Institute or" Standards and Technology in Washington D.c. 93 THE ENTHALPIES OF FORMATION OF SOME THISUBSTITUTED PHOSPHINES, PX Y„ (X = NMe : Y ^ CI, CN). n 3 - n 2 H. Al-Maydama, Arthur Finch, P. J. Gardner, A. J. Head, Department of Chemistry, Royal Holloway and Bedford New College (University of London), Egham, Surrey TW20 OEX, U.K. and G.Pitcher Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K. The enthalpies of formation at 298.15 К of the four compounds In the series P(CN)3< P(CN)2 The values for P(CN) and P(HMe ) have also been obtained by rotating-bomb oxygen combustion calorimetry under conditions where orthophosphoric acid is the only phosphorus-containing product. The results for P(NMe ) from both methods were in good agreement, but the results for the hydrolysis of P(CN) indicated uncertainty in the stoichiometry of this reaction. The enthalpies of vaporization of all six compounds have been derived from measurements of vapoui pressure over temperature ranges close to or including 29в.15 К. Enthalpies of formation for the gas state have been calculated and are discussed with reference to bond energy terms. 94 INTERNATIONAL SYMPOSIUM ON CALORIMETRY AND CHEMICAL THERMODYNAMICS JUNE 23-28 1991 , MOSCOW , USSR THERMODYNAMIC PROPERTIES OF FATTY ALCOHOLS M.H.MANERO.R.ROUTIE B.CORMARY, R.ARMENGAUD I.U.T. Genie Chimique Society SIDOBRE-SINNOVA Chemin de La Loge, 31078 Toulouse 31360 BOUSSENS FRANCE FRANCE Abstract In this work, a complete study is presented about the thermodynamic properties of natural saturated fatty alcohols in the CgH140 to С24Н50О range. The. properties studied are those necessary for Chemical Engineering calculations. We propose a number of estimative techniques . We also present experiments for vapour pressure laws. Results are presented in a way such that they can easily be stored in a data base. Properties varying with temperature are written in the form of mathematical laws, anu are recorded through their specific parametric values: vapor pressure, heat capacity and viscosity. The other properties are directly stored as fundamental data : normal boiling point, critical properties (pressure, temperature, volume and compressibility factor ), acentric factor and enthalpy of vaporisation. For all properties, laws of evolution according to carbon chain length, can be observed. All these results are stored in a data base that is included in ProSim simulation software. Then, vapour-liquid equilibria of fatty alcohol mixtures' are taken up. Numerous ebulliometric experiments are presented. They were run on various type? of fatty alcohol binaries, under different pressures ( from 10 to 200 mmHg ). Observed behaviours are close to ideal: the A.S.O.G.thermodynamic model associated with Perfect Gas Law are quite good representations of these thermodynamic equilibria. Thanks to the knowledge of these thermodynamic laws of behaviour associated with the created data base, we can use simulation softwares for Chemical Engineering calculations. 9Г THERMODYNAMIC STUDY OF THE THREE ISOMERS OF MH YDROXV&FNZENE. R.SABBAH and E N.LE.BULUKU. Centre dc Thermodynamiquc et de Microcatorimetrie du C.N.R.S. 26,ruc du 141eme R.I.A. 13003 MARSEILLE (France). By combustion calorimctry of small amounts of substance (1-3), sublimation calorimetry (4), differential thermal analysis (5-7) and heat capacity measurements, it was possible to determine the enthalpies of formation of 1,2-, 1,3-, and 1,4-dihydroxybenzene in the condensed and gazeous phases, their enthalpies of fusion and transition, and the temperature of their triple point and transition. From the experimental results, we could discuss the relative stability and determine the resonance energy of the three compounds. The experimental and theoretical vahies obtained from a calculation using a method of quantum chemistry (8) are in good agreement. The enthalpies of atomization enabled us to determine an energy value for the intramolecular Cb-OH bond in dihydroxybenzenes and to correlate it with previous results obtained from a study of alkancdiols (9,10). The enthalpies of sublimation were discussed.An intramolecular hydrogen bond was displayed in orthp isomer. Intermolecular hydrogen bonds associated to van der Waals interactions exist in dihydroxybenzenes. Their energy contributions were determined (11). REFERENCES 1) R.Sabbah,I.Antipine.Bull.Soc.Chim.Fr. 3 (1987) 392. 2) R.Sabbah,M.Cotcn.Thermochim.Acta 49 (1981) 307. 3) P.Kjnauth,R.Sabbah.J.Chem.Thermodyn. 21 (1989) 203 and 779. 4)R.Sabbah,[.Anlipine,M.Coten,L.Davy.Thermochim.Acta 115(1987) 153. 5) R.Sabbah,I.Antipine.J.Therm.Anal. 32(1987) 1929. 6) P.Knauth,R.Sabbah.J.Therm.Anal.,in press. 7) R.Sabbah.L.El Watik.J.Therm.Anal.,in press. 8) R.Sabbah,M.Gi!bert,A.Julg.Thermochim.Acta 10(1974) 345. 9) P.Knauth,R.Sabbah.CanJ.Chem. 68 (1990) 731. 10) P.Knauth,R.Sabbah.Thermochim.Acta 164 (1990) 145. 11) R.Sabbah,E.N.L.E.Buluku.Can.J.Chem.,in press. 96 THERMODYNAMIC РП0РЕНТ1ИУ OF £ -CAPROLACTAM. U.J.Kabo, A.A.Kosyrc, V..'J.Kruk, V.M.Sevruk, l.A.Yurshu, V.V.Simirsky, V.I.Uogolinsky Res. Inst, of Phys.-Cherc. Problems, Byelorussian State Univer sity, Minsk 220050, USSR. Heat capacity of crystalline» and liquid £-caprolactam at the temperatures 5 - 90 К and 340 - 520 К was respectively measured by vacuum adiabatic calorimetry and triple heat bridge method. Ther modynamic properties of caprolactsm in the temperature rango 0 - 550 К were calculated using our heat capacity resultч and data of Kolesov et al. [1] at tha temperatures 60 - 375 K. T/K CP,r/R A I V* л*п£/м 50 4.680 з.зьо 2.112 1.267 100 7.825 7.662 4.239 3.423 200 12.03 14.63 7.283 7-314 298.15 18.86 20.83 10.06 10.77 342.3KB) 23.21 23.68 11.44 12.23 342.3KD 28.93 29-33 17.1С 12.23 400 32.18 34.10 19. os 15.05 550 36.72 45.13 23-34 21.79 The saturated vapour pressure of solid caprolactam in the range 300 - 340 К was measured by the integral effusion Xnudsen method; InU'/PiO = C34.652 ?- C.JG5) - (1074! - 98) T_1 tir.d sublimation enthalpy val\i--; at tha average temperature of the measurements клв oalc-ulpfed Д ,,i,Hu(320 K) = 89.3 - 0.0 kJ»mol~ . It addition, the ,-•..':lima•.ion ontiial,.-y was directly- determinad by heat-conduction differ sn!.i'.:l i.nlori..ie ter: Д bH°(338 K) = 86.3 - 0.22 kJ-niol" . Using these data were obtained two values of entropy of gaseous catrolactai.i: S°(g,320 K) = 377.0 ~ 2.6 J'K~1 •iuol~1 and Sp(3,320 K) = 3*9-2 ± 1.0 J-K"1•mol"1, the disc repancy tn which was caused by th" difference in the sublimation enthalpy values, obtained by cdioriiiictric and effuuion methods. An isothenrall" jacketBc; с .'.огэmeter w-я used to measure the ener gy cC combuaiior of o>. рго1т..!,и'ч: Д .,H°(cr, 238. 15 K) = * -360376 t 1.46 Ычг.уГ1- front the inL'.i'arda and Iidrcun sp'-ctra of c-iprolactam in the at— lid stai: were estimated the normal v.ibretional frequencies. Sta tistical calculation ui' the ^-hemodynamic properties of ceprolac- tab in the ideal -gc; stnto '.-as cruvied c.t with an account of the contributions cf fore enor'jy unenutvuler.'": conformations . The uta- tia'ically calculated entropy 3°(^,320 К) = 374.25 J-K~1«mol-'1 ie in satisfactory agreement with the experimental values. She thermodynamic functions С°)Я./1'., д ^S°/R, Д^:°/ЯТ arid Ф°/Н of caprolactam in '"he ideal r.;s stui,fc are сол.твзрояй1ад1у: VJ.55, 43-80, 9.163 a:i3 3.].&/} ct :.Jn, :;iii;icriHure 'i ..- i<-?8.i?> К. HEFERKIJwKi 1) V.P.Kolesov, I.b'.Pnukov, :;.i,i.Skuru-oY. Zn.Pia. toxin.36(1962)770. 07 ON ТНК ADDITIV1TY OF THiS EHTHALPIES OF ALKYL DERIVATIVES OP URKA. 11? 1 1 G.J.Kabo, A.A.Kozyro; M.L.Frenkelf A.P.Krasulin, V.V.Simirskj. I.Res. Inst, of PhysrChem. Problems, Byelorussian State Univer sity, Minsk 220080, USSR. 2.University of North Texas, Department of Chemistry, Denton, Texas 76203-5068. We have previously proposed the additive method for calculati on of the thermochemical properties of alkyl derivatives of urea in crystalline and gaseous states on the base of systematic study of these compounds. We show here a principial possibility to apply shis method for calculation of sublimation enthalpies of mono-, di- and three alkyl derivatives of urea. There are 6 parameters in this method: two increments of substitution of hydrogen atoms for methyl group, three increments considering 1-3 interactions and one para meter, characterising energetic stability of basic compound (subli mation enthalpy of urea): AsubH(R1R2NCONHR3) " ДаиЪН(Ш2С0Ш2} + V&H(GIVN + + п.дДН(СН3)с + пкДДН(ССЮ + n-,uAH(CNC) + nJiAH(CCC) The calculation of additive constants is made for fore massifs н of values Даи>, > obtained: 1) from our measurements of vapour pressure by the integral effusion Knudsen method (calculation 1){ 2) from calorimetrlc measurements of Miroshnichenko et.al. [l] (calculation 2); 3) from measurements of vapour pressure by the torsion-effusion method of Piacente et.al.[2](calculation 3)i 4) from data, found by averaging of these three massifs with an account of statistical weight of each measurement (calculation 4). All experimental results were reduced to T = 298.15 К with an ac count of the heat capacity of crystalline and gaseous phases. Tab le 1 gives results for additive constants. Table 1. Additive constants determined from the sublimation enthalpies of alkyl derivatives of urea. additive constant calculation kJ-mol~1 12 3 4 ДflubH(HH2C0HH2) 98.80 95.60 92.50 95.87 ДДН(СН3)Л -0.80 -1.86 0.17 -1.13 Д. ДИ(СН3)С 6.61 6.76 2.00 5.72 A AH(CCN) . -4.48 -3.43 2.29 -2.18 ДДН(СШЗ) 2.08 1.05 7.95 0.20 д ДН(ССС) -0.88 -2.25 1.53 -1.79 Table 2 shows comparison between the calculated results and experimental values of Даиь^' We can make the following conclusions from our calculations: 1. There is a satisfactory accordance between the experimental H and calculated values of Aaub for every basis of data. 2« The systems of equations do not reveal the signs of unstability. 3. The systematic discrepancy in the values of Дau vH determined by calorimetry |,1l and our effusion measurements are probably cau- 98 eod by different character of vaporisation and the intensity of vaporisation in experiments» Though, differences between results [1] and [2] have a non-systematic character. . Table 2. The sublimation enthalpies (kJ.mol ) of alkyl derivatives of urea at T - 298.15 K. compound: our data : data [lj » data [2] : average data exp. calc. exp. calc. exp» oalc. exp. calc. i «йГв 95Гб «jiTs 95Т9 II 100.7 98.0 96.1 93»7 95.1 92.7 97.4 94.7 III 102.1 100.1 98.6 97.1 94.4 97.0 99.9 98.3 IV 103.0 101.4 100.4 98.2 106.8 102.8 101.7 100.0 V 110.5 Ю7.1 106.1 102.7 107.6 106.3 107.3 104.0 VI 104.7 101.7 98.3 97.0 108.4 110.2 104.6 100.0 VII 101.4 99.3 95.7 92.9 95.3 100.8 97.0 93.8 VIII 94.6 97.2 88.9 91.9 89.7 92.9 90.0 93.6 IX 101.4 103.6 96.8 99.6 97.7 100.9 X 101.0 101.5 101.7 101.4 101.3 100.7 XI 102.4 Ю4.7 96.8 98.4 100.9 104.1 XIIй 109.9 111.6 104.4 106.1 ЮЗ.З 104.0 Ю4.5 106.1 XIII 117.0 115.6 XIV 105.1 100.5 XV 106.5 101.0 average deviation 2.2 2. 3 2.8 2.7 I - ureaj II - methylurea; III - etbylurea; IV - isopropylurea; V - seobutylurea; VI - tertbutylurea; VII - 1,1-dimethylurea; VIII - 1,3-dimethylurea; IX - 1,1-diethylurea; X - 1,3-diethylurea; XI - 1,3-ditertbuthylurea} XII - butylurea; XIII - 1,3-dibutylurea, XIV - propylurea; XV - 1,1,3-trimethylurea. * The sublimation enthalpy of butylurea is reduced to T • 298.15 К without an transition enthalpy at T « 315 K. REFERENCES 1) V.P.Vorobjeva, E.A.Miroshnichenko, Proceeding of 5 All-Union conference on thermodyn. organic.сотр., Kuibyshev, 1987, 20. 2) V.Placente, D.Ferro, G.Delia Qatta, Thermochimica Acta. 158 (1990) 79. 99 A NEW APPLICATION OP THE FLAME CALORIMETRY. A TECHNIQUE FOR THE COMBUSTION OF ORGANOMETALLIC COMPOUNDS CONTAINING CHLORINE. S.N.Ha.liev, I.M.Khasanov, P.A.Gerasimov, A.J.Head. Inorganic Chemistry Department, Faculty of Chemistry, Tyumen State University. Tyumen* 625003, USSB. New College, London University, London, England. Well known is the problem of precise enthalpy defining for organometallic as well as for silicon and organoboron compounds. The usual techninue of bomb calorimetry combustion is not effec - tive as it causes a solid oxide film on the sample surface, which prevents it from complete combustion. A new technioue is therefore suggested [1] for the flame calo rimetry combustion of liouid silicon and organometallic compounds. To evaporate a sample out of the quartz burner, the energy of its combustion is used. That helps avoid the extra energy supply to the calorimeter for heating the sample [2,3]. The self-heating is obtained with the help of a metal device, which conducts the heat from the flame to the burner vessel and disperses the fine dispersed solid oxide of the sample in the glass combustion chamber. Thus, it becomes possible to evaporate the sample out of the burner and to burn it completely. The new techniaue has been further investigated for the calo rimetry combustion of organometallic compounds containing chlo rine. The present paper gives the results of the investigation. The free CI2 formed at combustion in the glass absorber wjth the anueous solution o-f N284.- г НС1 turns into the aoueous solution of HC1. The released energy of the process is measured with the total one. Two substances have been investigated: (СНз)8Ю1 and (CHz) H e (C2 50)2SiCl. The obtained value of &/H m[(CH3)3SiCl, liq,298.15K]= 1 = -390 ±6 kJ-mol- agrees with the reported ufHS,[ (CH3),rSiCl, liq, 298.15K3 = -284,5 ± 3,3 kJ-mol"1 № For the second substance the obtained value was ujH»,. [(СНз)(С2НсО)231С1, liq, 298.15K]=» a - 806* 20 kJ- mol-j The data have not been reported. REFERENCES 1. S.Hajiev, I.Khasanov, I.Usoltseva, patent №1520420 (1990) 2. J.Eckmen, F.Rossini, J.Res.NBS. N.3 (1929). p.597-618. 3. J.Thomson, Thermochemische Untersuchungen Verlag Ambrosius Berth. Leipzig. Bd.4 (1886). 3.15-18. 4. A.Beezer, C.Mortimer, J.Chem. Soc. (A). (1966). p.514-516. 100 PRECISION MEASUREMENTS OF THE COMBUSTION HEATS 01" SMAI.l. GftMH.Efi V.A.Rafeev. Yu , 1 . kubi sov, 'J. V. .-".vjori in, Т.У. Sorols) na, A.M.KorolPv Dept. of ln«st\t«.itf- о? Chemical Physic*,, Acad. Sci . USSR, !.4iV">?, f!05t:cw R'-'gied, CheiT'OeolDvfca, UStjR In the preaer.t work thernrocha-nic ».l investigation af succinic acid (I), pentaerytbrito! tetrani t:".a,i'> (JI) and cellulose iit.rp.te (III) was carried out i ;i automatic •: ntr.tiusti at\ calorfm^tiar (ACC-3W made by the Dept.. o-f the Institute ci- Chemical Physire С i'J a;ic (ло'-i Ч static—bomb calorl.iu.'ter V-C6-I1 V,'.'.\ to determine Lha Absolute accu racy o-f measurement o-f the enmbaation heal's of ACC-3M э-f small samp le*. The ener tiy equivalents o+ the? calorimeters were determined by- burning "K--S' benzoic pr)r),A^'Uyca! pure succinic iciti o-f "Fteppal" corporation, o Сотр. Calorimeter m,g n ""AU -Д.Н" Re-F. j/g Kj/mal V-06-1 '. 1.30 5 12637.01 4.7 940.510.& ACC -'*.M 0 , 07 6 ?2*>29.H±2i.0 941. 412.4 ACC -.'-"I 0. 16 6 12641.21 4.6 940.010.5 12670.01 1.6 9«'C. 410.2 _C3] "v-"6T-П T'.'o" 7 «;£Г."зГ"я7Г''о'4'бТн"Г21 ?•""" II ACC -3M О.ОУ-О,* A (5(67.4113.0 543.3*4.1 fii 13. vi 4, i :s,i.n. an. з ел] •3182.61 4.1 539.511.3 Г51 С 174. 61 в. i 5-1 I. 01?. 5 ti-1 V-06-11 5 10151.7* 3.3 III ; .o ЙСС ~3li o.;; 4 101Я0.21 P.O Calorimeter ACC-3M comhi nwij wi Lh th>* electronic balance having -6 the accuracy of l.io q permitРЧ to coniluirt fcr 25 min the precision measurements of I he !>c*t4 of- coisbiT.i <-,n fr_:»- tha иаз-s or sample O.0Z- 0.20 g with the si solute гогигжл- 15 ±20 j/g (954- -probabl 1 i ty!. pi v CRLX-.^E 1,L.N.Galprar in, V.S.Vi •.|ir>y.:l.-ov, ui.."< l.olcsov а.О ., i'hpi(r:od/rio'"ics o-f Chemical Compound-, Ьмгку. (190". • D;'. 2.L.V.Kuetova, lu.i.Rubtsciv, £, °, Ki • p: tt-.hev .-..,•-.., .1. Pli>-3. Ch(s>:> 50 (1976) 1903. З.Ригв and Лрг>1 , flu?-'. «'0 < I c>7<> > N 3. 4.Y.A.Lehpdev, fi.n.kUin, i:•• A. Mi roshnitchen..o. V; International Con ference on I her,-ncv) ,.-i,j-4i r.v. Н-дгяпЬиг.э, (MIR. <19H0> 17. S.D.L.Ornel Us, J . 1-1.Carpenter , S.R.tVinn. ftev.Sci . Inst. 37 <19B0' 907 6. E. Bur lot, T.Theme", M«m. : ••oue.Voa. 29 (1939) 2"6. 101 THERMODYNAMICS OF NORBORNENE, ITS POLYMERIZATION AND POLY NORBORNENE FROM О К TO 330 К N.N. Smirnova, B.V. Lebedev, Ye.G. Kiparisova Chemistry Institute, N.I. Lobachevsky State University, Nizhny Novgorod 603600, OBSR Calorimetric study results of thermodynamic properties of norbornene (NB), polynorbornene (PNB,); a synthetic rubber of ge neral purpose which- is widely used in industry under the name "Norsorex") as well as polymerization with ring-opening of NB containing double carbon-carbon bonds in the presence of metathe sis catalysts over the range О К to 330 К are shown. 1 I I J CHf-CH^ rm iJKB Temperature dependences of heat capacity for NB in two crystalline and one liquid states (Fig. 1) and PNB in glassy and high-elasticity states (Fig. 2) have been studied in a vacuum adiabatic calorimeter from 10 to 330 К at standard pressure with in 0.2 %. Fig. 1. Heat capacity of Fig. 2. Heat capacity of norbornene: AB-crystals Oil, polynorbornene: AB - glassy, CD - crystals CI, E - liquid. CD - high-elasticity. 102 The purity of MB sample studied is found to be 99.16 mole #', the first and the second cryoscopic constants are Д«2.3549 К ; B«-0.000289 К . Thermodynamic parameters of transition and melt- ing of NB have been determined: т£ -130.3*0.2 К; AtrH°=4.37±0.0 4 1 1 -1 kJ-mol" ; utrS°=33.5*0.4 J'K" .mol ; т£ца=319-45*0.05 K; AfusH°= 1 -1 3.48±0.06 kJ-mol" and^.us,S°=10.9±0.2 J К - mol . For PNB the glass transition temperature is Т?,=282±1 К; the zero entropy of " о —1—1 glassy polymer is estimated to be S (0)=7 J-K mol . From the results obtained the thermodynamic functions have been calculated between О К and 53C K. At T=298.15 К and p=101.325 kPa they are following for crystalline.NB: C°=134.2 kJ-mol"1; H°(T)-H°(0)= 28.24 kJ.mol'1; S°(T)=200.9 J-K ~1 mol"1; G0(T)-H°(0)s«$1.67 kj mol"' For high-elasticity PNB 160.8; 20.94; 147.4; -23.01, respectively. The energy of combustion of PNB is measured, and the enthal py of combustion as well as the thermochemical parameters of for mation of PNB are calculated. At 1=298.15 К and p=101.325 kPa н /|/1 1 high-elasticity PNB has the following values: д ошь °=~ 75'' * 1 1 1 ±0.7 kj-mol" ; Д£Н°—8.65±0.7 kJ-mol" ; A£S°=-545.4±0.5 J-K"lmol~ -1 and 4fG°=-154.0±0.9 kJ-mol . The thermodynamic parameters of NB polymerization in the range О К to 330 К are calculated and listed in Table. Table Thermodynamic parameters of bulk polymerization of norbor- nene at p=101.325 kPa. T, К Physical state - Дво1Н°, - ADolS°, - AoolG°, nf mnnnmfir and POJ- . P?-1 . P0J- . polymer кJ»mol- 1 J-K -1mo l- 1 kJ-mol- 1 0 oil; gl 55 -7 55 100 oil; gl 55 5 55 200 cl; gl 62 51 52 298.15 cl; h.e 62 54 46 330 1; h.e. 65 63 45 с - crystalline; gl - Glassy; h.e. - high-elasticity; 1 - liquid. 103 ENTHALPIES OF COMBUSTION AND FORMATION OF POLYMERS Ye.G. Kiparisova, B;V. Lebedev Chemistry Institute, N.I. Lobachevsky State University, Nizhny Novgorod 603600, USSR A detailed analysis of all studies on the experimental de termination of enthalpies of combustion for 115 polymers as well as the calculated values of enthalpies of their formation from simple substances at T-298.15 К and standard pressure has been й and 0 made for the first time. More than a half of Асошк ° AfH values of polymers were obtained in the laboratory of authors. The values of enthalpies of combustion and formation were classified according to the degree of reliability of their de- termination depending in many respects ирод the comprehensive in formation on the characteristics of the polymer samples studied, apparatus and procedure for- measurements of enthalpies of com bustion and correction consideration. The enthalpies of combustion and formation for polymers were summarized in Tables. In those Tablee the polymers are ar ranged in accordance with the recommendations of IUPAC on the H and polymer classification flJ. The values of Acomh ° Л*Н° recommended to make the calculations above are specially se lected. The main peculiarities of the polymers as objects of ca- lorimetric studies are discussed. The effect of various factors 0 on the Aoonrt)H values of the polymers hac been evaluated. Up-to-date apparatus and methods for the determination of enthalpies of combustion qf the polymers as well as the main cases of application of Дсот^Н° and Д£Н° values in contempo rary thermodynamic and thermophysical calculations are briefly considered. REFERENCES 1) N.A. Plate, I.M. Papisov, Vysokomol. Soedin. ЗОА (1990) 2608. 104 STANDARD FORMATION ENTHALPIES OF SEVERAL CROWN ETHERS. S. B. Kopnyshev, V. P. Vasilyev, V. A. Borodin Chemistry-engineering institute, Ivanovo, the USSR. Standard combustion enthalpies of three crown ethers (18-crown-6, di-benzo-18-crown-6, benzo-16-crown-5) were determined by the direct calorimetric method. The heats of combustion were mesured by the precise steady-bomb and isothermal-she11 calorimeter (V-08-MA) /1/. Standard formation enthalpies were calculated for the said compounds. The following results were obtained: Compound -Де H*, kj- mof - Дj, H°, kj»mol" 18-crown-6 7116.1 2.8 1037.0 2.9 di-benzo-18-crown-6 10512.5. 2.4 787.7 2.6 benzo-15-crown-5 7622.5 4.7 745.0 4.7 The point of interest is to evaluate the strain energy of the cycle (En); En -Aj H*exp -4|Hecal, where^H°cal is calculated after the additive rule in accor dance with group contributions obtained for the strainless com- paunds. _t The quantity дНр - -23.4 k>mol~ for the group (O)-CHj-(C) was taken from the paper /2/. Standard formation jnthalpy of the group (C)t-0 was obtained through processing the experimental data by the solidity formation enthalpies of the 16 compounds with general formula R|-0-C-Re. The strain energy at the ring of 18-crown-6 (En) was found to be 55.0 kj. mol"' . References: 1) V. P. Vasilyev. V.A.Borodin, S. B. Kopnyshev. J.Phys. Chem. 62 (1988) 2243. 2) A. N. Kizin, Y. A. Lebedev. Reports of the USSR Science Academy 262 (198?) 914. 105 ISOMERISATION EQUILIBRIUM OP MENTHEHES AHD HYDROCARBONS ENTROPIES OF CTCbOHEXANE'S SERIES. G.N.Eoganov, G.J.Kabo, L.G.Stolyarova, Z.A.Pilippenko Institute of. Technology, Mogilev, USSR. Equilibrium of isomerisation of eight o- and p-menthenee have been studied by impulse-chromatographic method on aluminium oxide within 523-623 К and values of entropies of reactions have been obtained (table). It has been established, that their values depend mainly on the difference of molecular symmetry, entropies mixing of optical and conformational forms, as well as barriers of rotation and size of outcyclic groups for each isomer. The values of parameters of additive Entropies of lsomeri- scheme calculation of entropies of satu sationj gas, 573 К rated and unsaturated hydrocarbons with six-membered cycles have been calculated by using known values of entropies sub Reaction АЛС т stances and reactions. The method of cal 1 culation was based on early proposed ap J»mol •V proach /1/, in wich classification of atoms except their chemical individuali ty, valence and encirclement supplementa — I J -13,1+1,7 ry characteristic, named "cyclicity" of atom, are introduced. It takes into con sideration participation of atom in the formation of the molecule cyclical system. 9,8+1,7 In this case except atoms C? (i- carbon atom number in the first encircle ment of the considered carbon» с - "cyc- licity", that is the number of carbon atoms in the cycle) spiro-atoms C°'f0iand nodal atoms C?Y,Ca are singled out in bi- cyclic hydrocarbons. The double bond is considered to be binominal cycle. Thus, 6 ,6 1-methylcyclohexene has 4Cg, C^' , c| ,01 kinds of carbon atoms. The values of entropies have been evaluated on bases their "essential" mea ning. m Sm = Sm + Ч^'А^х • 4+2,3 where 6* - rotation nurabev of symmetry; ^Smix = н1а2П (п ~ number asymmetric ele- -"""~~~""""""~-———— jnents) - entropy mixing of optical forms. Average difference of calculated entropies (gas; 298,15 К ) for 36 substances and reactions from experimental are formed +1,5 J-inol -K'• 1 REFERENCES 1) G.Kabo, G.Roganov, Doklady AN BSSR. 30 (1986) 832. 106 ENTHALPIES OF FORMATION OF ALKYLTERTALKYL ETHERS. A.M. Rozhnov, K. 8. Sharonov Chemical Department, Kuibyshev Polyteohnicil Institute, Kuibyshev 443010, U.S.S. R. Alkyltertbutyl and alkyltertamyl ethers are widely used in industry as high octane components of motor fuels without tetraethyllead. The investigations of the equilibrium of liquid phase reactions of ether synthesis from alcohols and isoolefines have shown that alcohol-isoolefine-ether system is non-ideal. The experiments have proved that with changing ratio alcohol / isoolefine from 1 till 3 the concentration constant of equilibrium K,. lessens, and at ratios 3 and higher K^ becames The case with the synthesis reaction of methyloumyl ether (1) shows that the values of K^ found in the excess of methanol (in the conditions of stable values for a given temperature) can be used for a finding ArH^ of reactions. To support the correctness of this conclusion we performed the investigations on the equilibrium of synthesis of tertamyl- methyl, n-amyltertbutyl, n-butyltertbutyl, isobutyltertbutyl and seo-butyltertbutyl ethers. The experiments were made in a liquid phase with the molar ratio of aloohol/isoolefine equal 4 in the temperature range 313 to 413 K. Values of ДрН^ of ethers were found. Simultaneously the values of AvapHJj| and the enthalpies of combustion were found for the ethers investigated. The enthalpy of formation for amyltertbutyl ether was calculated from the results of the investigation of the equilibrium of the synthesis reaction in a gaseous phase. The comparison of the results received showed that the data of a liquid-phase equilibrium and the results of oalorlmetric measurements produced results agreable among themselves. They support the conclusion of paper . (1) about the possibility of using R^ , found in the excess of alcohol for the definition of дгН^ . On the basis of calorimetric data and results of chemical equilibrium the enthalpies of formation of ethers were found. Values of ДрН^ for 298.15 К in a gaseous phase (kj'inole"1) are shown below: for methyltertamyl ether (-305.4+1.0); for n-butyl- tertbutyl ether (-359.9*4.2); for IsobutyltertButyl ether (-368.5+ 3.4); for sec-butyltertbutyl ether (-379.2+4.1); for n-amyltertr butyl ether (-380.6+8.8). REFEREMPF 1) A.MLRozhnov, V.V. Safronov, V.I. Alenin, K. a Sharonov, Zh-Flz. Khlm. 62 (1988) 2902. 107 RELATIONSHIPS IN PROPERTIES AND THEIR PROGNOSIS ON THE BASIS •.V INDICES OF MOLECULAR BONDAGE OF1 ALKYL8ENZENES , ALKANES AND THF.TR FUNCTIONAL DERIVATIVES. T. N. Nesterova, A. A. Pimerz-in, A. G. Nazmutdinov, L. A. Medovschikova Chemical Department, Kuibyshev Polytechnical Institute, Mjibyshev 443010, U. S. S. R. On the basis of our own experimental data on the investigation of chemical and phase equilibrium, as well as lite rature daVa, the analysis was made of the interrelation of the thermodynamic and physical-chemical properties of compounds with i l's structures of their molecules. Large massifs of data were analysed for the compounds of the following classes: alkans, als^lbenzenes, alkylphenols (including space-impeded), halogen- alkans (mono- and disubstituted), halogenalkylbenzenes and poly- htuorjenbenzenes ( halogen- fluorido, chlorine, bromine), cyclo- alkvlbenzenes (cycles-pentyi, hexyl, adamantylj, alkylbipnenils and' bis-(phenil)alkanes, alkylnaftalins, indans and some cyclo- fvlkanes. It was shown that in prognozing the majority of properties discussed (enthalpies of vaporization and formation, criMcr.l temperatures, pressures and volumes, normal boiling temperatures, enthalpies of sorbtion ets.) in their application :,o the compounds of the classes discussed, it was necessary to have the depth of detalization of the scheme of calculation, including interaction of four consecutively placed atoms in a molecule. The analysis of different additive schemes and empirical correlations permitted to conclude that the best way to reach this air*, is to use the method based on the application of the thsorv of graphs and indices of molecular bondage by Randioh. we have significantly modified this method: values of practically all code numbers, characterizing separate atoms or structural i'rdgiiionts are tuneable Along the parameters of experimental data The equation L= f С'ЛУ-} (where L are properties, -nX is summary index of molecular bondage of a compound) are found from the properties of one of the most investigated homologous series in each case. The discriminating ability of °"\X is very great. The value cf the cole numbers of atoms, partisipating in transporting interaction-of substitutes of atoms or fragments in a molecule, predefines the amplification of weakening of the interaction 3ffeot. All reported is illustrated by factual material, showing • cr-^nostic possibilities of the method in comparison with other •jaioulating methods. 108 JBNTHALPIES OP COMBUSTION OP SOME CHLORO-, SULFUR-, NITROGEN- AND PHOSPHORUS-CONTAINING ORGANIC COMPOUNDS OBTAINED BY NEW METHODS. T.I.Grornova, M.V.Lyubarsky, S.V.Rudakova All-Union Research Technological Institute of Herbicides and. Plant's Growth Regulators, Ufa,US3R. The given report results from the studies carried out in the thermochemical laboratory of our Institute recently. In particular, the problems arising during combustion energies determination of chloro-, sulfur-, nitrogen- and phosphorus-containing organic compounds by the bomb calorimetry method are analysed in the re port. It is shown that traditional methods and means do not always result in complete combustion of compounds.lt is especially true of compounds with increased chlorine or phosphorus content.Our method (without arsenic) is effective enough, it presupposes combustion of chloro- or chloroaulfur-containing organic compounds simulta neously with elemental sulfur. The advantages of the given method are discussed and the problem of calorimetric system bringing to the unique final condition is considered. It is shown that besides auxiliary compound function, sulfur can serve as a standard in sulfur- and ohlorosulfur-containing compounds calorimetry. The results of combustion energy determination of p-chlorobenzoic acid by new alemental sulfur method are given. The aspects of platinum catalysts usage in organophosphorus compounds combustion oalorimetry are discussed. The positive in fluence of those on the outcome of burning is shown. Their usage is recommended also for compounds with increased nitrogen content to avoid the soot formation» The results of enthalpies of combustion determination for 6 compounds: 6-chlorobenzooxazolone, 6-chloro-2-aminobenzothiazole, 2,6-diohlorobenzothiazole,. o-chlorobenzosulfonamide, N-phosphono- methylglycine and N,N-bis(phosphonomethyI)glycine are given as examples. They account for 1 .ДСН° (C7H402NCl,cr, 298.15 K) = -(2999,8 + 3,5) kJ'itiol"" 1 ДсЦо (C7H5N2ClS,cr, 293.15 K) = -(4090,!; + 4,0) kJ-mol" 1 ДСН° (C?H3NCl2S,cr, 298.15 К) о -(3895,9 + 4,6) kJ.mol" 1 ЬСИ£ (CgH602NClS,.cr,298.15 К) - -(3526,7 + 7,0) kJ.mol" ' -1 ДСН° (С3Н805РИ, cr, 298.15 К) = -(1681,4 + 9,8) kJ-mol -1 дсн° (c^OgPgN.cr,298.15 к) = -(2499,3 + 9,4) kJ.mol respectively. 109 THE ENTALPY OF COMBUSTION OF TRI-N-BUT7LPH0SPHATE. P.A.Erastov. V.A.Petrunin, A.V.Tarasov, N.l.Fantalova State Union Eeserch Institute of Organic Chemistry and Chemical Engeneering, Moscow, 111024 U.S.S.R. The energy of combustion of tri-n-butylphosphate was determined In rotating-bomb calorimeter. TBP was fractionally distilled under reduced pressure. The purity of the sample was assessed as 99.95 moles per cent by chromatographic analysis. The combustion bomb was lined, with platinum .Approximately 0.3g of sample into the terylene. film bag was weighed into a gold crucible. The completeness of combustion reaction was verified by determinations for carbon dioxide trough absorption in Ascarite. 3mall carbon residues ( 0.5-1.2 mg ) were present in many of the calorimetric experiments. The chemical composition of carbon residues was confirmed by electron spectroscopy. Our C0_+carbon residues measurements recovered 99.98 per cent of the theoretically available С , based on the mass of the sample. Ion chromatography was used to analyze the bomb solution quantitatively for orthophosphate and pyrophosphate ions. The results of the combustion experiments on tributylphosphate in a.bomb containing 4.0 cm of water are summarized in tabl 1. The corrections to standard states and for hydrolysis of pyrophosphoric asid to orthophosphoric acid were made essentially according to the procedure described by Kirklin and Domalski. The standard molar enthalpy of combustion for the reaction at 298.15 К is: (C4Hg0)3l'0(liq) + 1802(g) = iaC02(g)+H3P04(soln.H3P04'200H20) + 12H20(Iiq) дН =-(8060±12)kJ'mol~ . The derived enthalpy of formation is: -1 AHf=-(13S2±12)kJ'mol . The value of the enthalpy of combustion for TBP reported by Nikolaev et al. ,-(7973*12JkJ'mol , is in disagreement with that from this work. This disagreement is considerably higher than the sum of the assigned uncertainties, and might well arise from the sample used by Nikolaev et al. having been insufficiently characterized, and from different methodology. REFERENCES 1) D.A.Kirklin, E.S.Domalski, J.Chem.Thermodynamics 1988,20,743. 2) A.D.Starostin, A.V.Nikolaev, Tu.A.Afanas'ev, Bull.Acad.Sci.Chem. Sect.1966,1303. но Tabl 1. Results of combustion experiments with tributylphosphate. Expt no. t 2 3 4 5 дТ/К . 0.87440 0.87933 0.86577 0.88227 0.86940 Q(total)/J -9410.2 -9462.9 -9317.3 -9494.8 -9356.3 Q(film)/J 526.8 548.9 537.6 530.1 548.1 Q(HN03)/J 0.4 0.4 0.4 0.4 0.4 Q(H3POd)/J -1.7 -1.7 -1.7 -1.7 -1.7 Q(WC)/J 5.0 5.0 5.0 5.0 5.0 Q(cabon)/J -19.2 -13.8 -24.3 -22.2 -41.4 m(sample)/g 0.2942 0.2952 0.2915 0.2973 0.2933 ли /J g -30247.8 -30230.7 -30189.7 -30215.9 -30159.9 THE ENTHALPIES OF FORMATION AND VAPORIZATION OF SOME KETONE'S PEROXIDES Yu.P.Pavlovsky, N.Pasadakis Dept. of Technology of Organic Substences, Lviv Politechnical Institute, Lviv 290646, USSR Next ketone's peroxides were investigated in this report! t-Ba-OO^-J t-ЫО Ei Ъ-BurOO CHz-CH(Me)2 1 2 Ъ t-Bu-00 V CH2- C-O-ft t-bu-OOy-(Me t-Ba-OO' Me ° 4 5 Me- Enthalpies of combustion иеге measured in a bomb isotermic calorimeter, but enthalpies of vaporization in Calvet type microcalorimetor using ampoul method. The combustion calorimeter, мав calibrated with a bezoic acid and microcalorimeter with the controling samples of decane and dodecane, characterised early in Lunds University, Sweden. The values measured in calorimetric experiment led. to' the equilibrium conditions} each series of measurement contaned 5 - 6 experiments. Purity of the investigated substances Mas above 99,SX mol. The experimental results are given in the table. -ДсН (298K) -d f H (298K) A vapH С298)0 Peroxide, state kJ/mol 1,1 8307,0+/-8,6 549,9+/-в,7 67,71+/-0,68 2,1 7826+/-Ю 612+/-Ю S8,35+/-0,92 3,1 9D25tO-t-/-8,4 771,2+/-8,5 64,62+/-0,29 8710+/-12 813 +/-12 74,9В+/-0,64 5,1 10662,2+/-6,3 8&&,6+/-6,5 72.2+/-1.1 112 TlbKu.OCHKi.il 3TRY Of VAPORIZATIOM OF SOME ORGANIC OXIGEN COHTAINIHU CYCLIC COMPOUNDS M.S.Kachurina, Yu.Ya.Van-Chin-Siun, YU.G.Hnitriew, K.Z.Kotovich Lvov Politechnical Institute, Ivov, USSR The enthalpies of vaporization of alcyl glycidyl ethers O-CHg-CH-CHgO-R, where R = -C^ (I); -^Hg (II); -CH(CH3)2 (III){ -CH2CH(CH3)2 (IY)} -C^CH2CH(CH3)2 _ Com- : Temperat. : : ,: AvapH, kJ»mol A . B.IO-». r- pound ; range, К ; j |p _T data .calorJLnetrical I 285-313 26,667 5,74 47,7+1,2 48,75+0,35 II 286-308 25,995 6,23 51.8+1,3 53,71+0,39 III 286-311 24,657 5,31 44,1+1,1 - IY 294-313 25,729 6,07 50,4+1,3 51,03+0,37 Y 293-313 27,450 6,71 55,8+1,4 - YI 288-309 25,297 5,84 48,5+1,2 50,55+0,37 YII 295-321 26,816 6,43 53,3+1,3 53,89+0,40 YIII -- - - 71,03+0,43 IX - --- 46,15+0,48 X - - -- 48,23+0,52 Analysis of the values of enthalpies of vaporization of Carbo- and Heterocyclic compounds show, that for small cycles recommended to изо correction during the calculation of ent halpies of vaporization, which depends on the nature of hete- roatoms in the cycle. IIS STANDAED ENTHALPIES OF FORMATION OF TRIS-DIPIVAL0YbMETHANATE3 Sc(III)$ Y(1II), La(IIl) AND THE MEAN METAL-OXYGEN BOND ENERGY P.A.Gerasimov, A.I.Gubareva, N.E.Fedotova, I.K.Igumenov Dept.of General Chemistry, Kuzbas Polytechnic Institute, Kemerovo, USSH The Institute of Inorganic Chemistry, USSR Academy of Science, Siberian Division, Novosibirsk, USSR Thermochemical constants and calculated bond energies metal-oxygen (M-O) are necessary for the energy characteristics of /s-diketonates used in the .production of different kinds of films, especially superconductive ones. Such data on tris-pivi- aloylmethanatee of Sc, I and La are not available in literature. Synthesis of the compounds under investigation was carried out using common technique plus.fourfold vacuum sublimation. Calorimetry was carried out using a precision rotating bomb calorimeter calibrated with the standard benzoic acid K-I (unce rtainty 0.02$). The pressure of oxygen in the bomb was 3.04 mPa. Complexes were burnt in pellets with mass about 0.1 g. For complete and even combustion of a compound benzoic acid (0.4 g) was used as an auxiliarycompound. Gaseous products of combustion were analysed on the CO, contents using the technique of Rossini, CO contents was control led with the help of indicator tubes. X-ray analysis showed that the solid products of the combustion offt-diketonates unde r in vestigation were metal oxides. From the calorimetric experiment were estimated the values for the energy of combustion (i_U°) and the enthalpy of forma tion (A,.H ). The enthalpy of sublimation of complexes (&suof) was calculated using temperature dependence on steam pressure measured with the help of a high-vacuum device and the technique by Laingmur . From the given thermochemical cycle the bond energy (E(K-O)) was calculated for each complex. The constants (kJ/mole) obtained are given in the tablet H A Complexes -A,cU°(c) -UfH°(c) Asub. - fH°(g) B(M-O) Se(DPM)3 19546,8*23,5 2509,7*24,0 93,5*0,9 2*15,8*24,0 2537*12 Г (DPH)3 19515,6*17,5 2639,J*18,0 158,0*1,1 2481,2*18,1 269,9*12 a La(DPM)3 19307,2*24,2 2692,5*24,6 175*10 2517,5*30,1 277,1*12 aestimated (M-O) bond energy depends on the nature of a complex-forming element and increases in the order: Sc(III), 7(111), La(III). 114 ENTEAbPIES OF FORMATION OF SOME DERIVATIVES OF DIACETYLENE V.A.Lukyanova, S.M.Fimenova, L.P.Timofeeva, M.P.Kozlna, V.P.Kolesov Chemistry Department, Moscow State University, MOSCOW 119899, U.S.S.R. The present work Is a part of a project to determine the energies of combustion and the enthalpies of formation of some conjugated diynes. Generally, these compounds are not suitable for studying by combustion calorimetry, since they tend to deto nate on Ignition. By that reason, little or no Information is available on their energies of combustion or enthalpies of formation. _ In this work the values of AQU° of 1,4-dimethylbutadyine-1,3 (I), 1-methyl-4-cyclopropylbutadyine-l,3 (II) and 1,4-dlcyclopro- pylbutadylne-1,3 (III) have been measured using calorimeter with a stationary bomb. Weighed amounts of samples (<0.1 g) were placed Into terylene film bags. To obtain clean combustion, ben zoic acid was burnt as auxiliary substance In the combustion ex periments with (II) and (III). (I) nas burnt as a solution in organic solvents under reduced oxygen pressure. At these conditi ons it was possible to avoid explosions and soot formation. The results of the experiment are summarized In the table. Results and derived quantities at 298.15K (kJ>mol~1) Table Compound -A0U°(l) -A0H°(l) A^d) A^i° A^H°(g) _ __„__^_____^_.___.. 33g Q46 у ^^ зте.йё.т II 4720.0+6.7 4725.0+6.7 433.5±6.7 51.9 485.3±6.7 III 5863.3±1.4 5S69.5+1.7 505.2±2.2 58.2±1.0 563.4+2.4 Using AjH°(g) values listed In the table, we calculated the Gt-(Ct) additive group contributions. Values Ct-(Cf) obtained -1 using AfH°(g) (I) and (II) are equal to 116.0 kJ-mol and -1 115.0 kJ-mol consequently and are close to the value Ct-(C) given by Benson et al.(115.3 kJ-mol"1 i1]).It means that there is no evidence of essential specific Interaction of non-bonded groups (e.g. conjugation energies) in these molecules. The _1 Ct-(Ct) value calculated using Ajtf'dll), 99.6 kJ«mol , is significantly less than others. 1 Group contribution value for Ct-(Cf) (123.6 kJ«mol~ 121) ba sed on estimated value AjH°(g) of butadylne is probably too high. REFERENCES 1. Benson S.W., Cruickshank F.R., Golden D.M. et al., Chem. Rev. 69 (1969) 279. 2. Shaw R. Thermochemistry of acetylenes. Ch.3 in: The Chemistry of the Carbon-Carbon triple bond, p.1. Ed. Fatal S., Wiley, Chichester (1978) 69. По THE NEW METHODS OF THE LOW VAPOUR PRESSURE DETERMINATION Revelsky I.A., Zirko B.I., Kostyanovsky R.G., Kurochkin V.K. Institute of Chemical Physics, Moscow. The accurasy of the known methods of the vapour pressure determination (P ) is high only in case of the ultrapure compo unds. But the purification of the compounds and the determination of the purity's degree is very time consuming and in many cases can't be fulfilled. The method being developed by us is based on the sequen tial saturation of carrier gas by ultrapure vapour of the compound being investigated and of the standard compound for. which the vapour pressure is. known at the temperature of the de termination. The vapours of the compounds'are made ultrapure with the help of the chromadistillation or it's combination with EC during the process of the determination of the. P The registration of the "zones" of the satucrated ultrapure vapour of the compounds with help of the gas density detector (GDD7 and flame ionisation detector (FID) allows to determine the Px-fi (as has been shown for n-alcanes C.~-C.„) *n the range ot 10 - 10 Pa. With the accurasy about 3S' relative. The calculation of the P , at the temperature TJ is Ti made using the formula: •/hi ' 7h.| / h \ M . -M xIi V^stJ T1 I hx У М »t/ • T1.Vnc.g. stTi where h . h . ,h ,h . ,h ,h , -the-"zone's" X x Bl x GDDT "GDDT FIOT FIOT FmT ^FID,. 4 4 4 M '1 ,x heights, registered for the vapours of the compound and the standard compound at the temperatures T. and Ti-, M , M ., M .- molecular weights of the compounds. Standard compound and carrier gas, correspondingly! The vapour pressures P and P . at the temperature Т. are in the linear dynamic 1 range as 1 of GDD and FID. 116 SOME THERMODYNAMIC CHARACTERISTICS OF VAPORIZATION OF 1-BROMnpERFLUORO-n-OCTANE Aytkeeva Ch.A., Druzhinina A.1., Varushchenko R.M. Moscow State university. Chemical Dept.,Moscow 119899, USSR The perfluorotctilbromide is a promising coeponent for blood substitutes and oxygenating Media, which are of importance for biology and medicine. In this paper the results of measurement of saturated vapor pressure p and boiling temperature T mra presented. The data were obtained by comparative ebulliometric technique in the temperature range 329 - 414 К and pressure» from 39 to 973 gPa with errors of determination of p and T being equal ± 0.OO6 К and ± 13 - lb Pa. The purity of the sample determined chroaatogra- phically was 99.9 mass.X. The invariability of sample during the processes was monitored by measurements of boiling point values under the same pressure before and after recording the p-T-curve. The data on vapor pressure fitted the semi empirical equations of dependence -RTlnP • em, .resulting from the Klapeyron equa tion. This method of approximation allows ono to obtain the equati ons of temperature dependence for saturated vapor pressures, en thalpies of vaporization AyH and differences of heat capacitances of gas and liquid AC as well as to take into account the deviation of vapor from ideality and to evaluate errors in ДуН and AC i In p (Pa) = A + B/T + ClnT + DT (1), 2 AvH (J/mol) = R AZ<-B + CT + ОТ ) С2), AC AyH(298) A H«T > AC <29B) y>(293) A» T D y n c c V kJ/mol kJ/mol J/K mol g/cm3 К MPa cm /mol 37.67 lOl.O 1.9134 0.46 346. 0 1.39 779. О + 0.99 + O.SO + 14.0 + O.O004 Reference Cll. L.P.Fllippov, "Methody rascheta i prognozirovanlya svoistv veshchestv", Moscow, MSU Publishers, 19B3. 117 THERMODYNAMICS OF VAPORIZATION OF ORGANIC COMPOUNDS R.M. Varushchenko Moscow State University, Chemical Dept., Moscow 119897, USSR The thermodynamic characteristics of substances in the region of gas-liquid phase transition are extensively used for various scientific and technical purposes. The temperature dependence of saturated vapor pressure is of utmost importance among these characteristics because all thermophysical properties of fluids in Hide range of its state parameters could be calculated on . the basis of vapor pressure data. In the Laboratory of thermochemistry of the Moscow State University a fundamental base was developed for the determination of thermodynamic characteristics of vaporization of individual orga nic substances. A method of precise determination of saturated vapor pressure by comparative ebulliometric technique was developed. An original experimental facility was constructed: the volume of liquid sample was reduced to '4 - 6 cc in a modified differential ebulliometer of Sventoslavsky type. P - T parameters are determined in the range of temperatures 293 - 530 К and that of pressures 2.6 - 101.6 kPa. The precise data for this range allow one to extrapolate reliably the vapor pressure values to low and high temperature ranges. The experimental determination of the heat of vaporization is carried out at 29BK emplolng LKB vaporisa tion calorimeter (Sweden). The densities of liquids were determined in silica picnometers of small volume (1 - 2 cm )'. The thermodynamic properties of 90 practically important orga nic substances of various classes were studied, the most of them (80) measured for the first time. A set of experimental p-T-data was obtained. The errors of determination of temperature and pressure are + 0.006 - 0.01 К and 16 - 26 Pa correspondingly. For a number of substances the enthalpies of vaporization were determined calori- metrically; the densities of liquids were obtained in the tempera ture range 293 - 3S3 K. A method of approximation of p-T-data developed in this work permits us to obtain the equations of temperature dependence for saturated vapor pressures, enthalpies of vaporization, and differences of heat capacities of gas and li quid, AC , and to estimate errors in AH and AC .The normal boiling points and enthalpies of vaporization at 29В К were calculated. The values of enthalpies of . vaporization obtained directly and the calculated ones match well in the error limits, thus speaking in favor of absence of significant influence of molecules dimerizatlon in vapor phase on the AH values. The variation of thermodynamic characteristics in the studied series of substances was shown to be a function of separate parameters that depend on the energy of molecular interaction and close order in the liquid phase. Bond contribution method was used to predict the vaporisation enthalpies for a number of compounds at 298 KJ a role of dipole moment for a calculation of AH of polar substances was revealed. The summing up of p - T data and densities according to the corresponding states low allowed us to obtain the necessary input . information, including critical parameters,which is necessary for calculation of practically all thermophysical properties of a substance in a wide interval of temperatures using thermodynamics scaling technique. не ENTHALPIES OF VAPORIZATION OF CONDENSED BICYCLIC HYDROCARBONS AND THEIR OXYGENATED DERIVATIVES A.A.Pimerzint V. S. Tsvetkov, E. M. Sveshnicov Chemical Department, Kuibyshev Politechnical Institute, Kuibyshev 443010, USSR Condensed bicycHc hydrocarbons and their oxygenated derivatives are of significant theoretical interest and find broad practical use. However their thermodynamic properties and particularly enthalpies of vaporization have not been investigated well. Ebulliometrie method was used to investigate temperature dependencies of the pressure of saturated vapour of some benzodicxanes CBDOJ, tetralines (TTL3, indans CINDJ and naphtha lenes CNFT) with methyl, ethyl, isopropyl and tertbutyl substitu tes. The derivatives of 1,3-BDO were synthesized by the condensation of alkylphenols with formaldehyde in acetic acid. Alkylsubstituted TTL, IND and NFT were received by the alkylation of bicyclic compounds with olefins or alkyl halides. Individual products were separated and cleaned by multiple distillation in vacuum or by recrystallization. The purity or specimens according to GLC data was not less than 99,8 mole percent. Errors in the temperature and pressure were +0,003 К and +13 Pa Сmean in the investigating range) accordingly. Normal temperatures of boiling and the enthalpies of vaporization of the above-mentioned compounds were calculated from processing P-T-data. It has been shown that the prognosis for AyH£ of mono- and bicyclic hydrocarbons with allcyl substitutes as well as the ones containing heteroatoms in cycles can be made correctly with the use of indices of molecular bondage C1"3*). So it was recommended for 298,15 К : for cyclic hydrocarbons: A 4 , 3 V a»e = 6,5465 + 4,4883*C - ;K) for compounds with aromatic function: I 3 , 3 , 3 lg V£ee= 0,ai2ai+l,6395xC - x)+lr4071*lgC- ^-0,008008«C- x) Code numbers, characterizing С-atoms of the aliphatic chain are analogous to those received for paraffins; code numbers. Thus 6™t =3.7 for IND. The quality of prognosis for АуН°вв is illustrated by some derivatives of IND. Compounds "" ' eaa,exp "** v£.«,««i IND 49,21 9,6506 49,00 4,7-di-Me-IND 59,09 12.0011 59,07 4,6-di-Me-IND 58,67 11,8953 58,61 1,1-di-Me-IND 5Й.0О 10,3420 51,95 1,1.4,7-tetra-Ma-IND 62.27 12,6235 61,73 1,1,4,6-tetra-Me-IND 31,60 12,6252 61,74 119 EFFECT OF TEHFERATURE AND PRESSURE ON THE EXCESS ENTHALPIES FOR METHANOL UITH ETHANE, PROPANE, ANO BUTANE J.B. Ott. J.T. Slpowska, and R.M. Izatt Department of Chemistry, Brlghara Young University, Provo, UT USA Excess enthalpies (H§) have been measured for methanol with ethane,1 propane, and butane in the temperature range from 298 to 348 К and the pressure range from 5 to 15 HPa. The H£ results are strongly dependent upon temperature, with C§ greater than zero. The pressure effect Is large and positive for (methanol + ethane), smaller but still positive for (methanol + propane) and still smaller for (methanol + butane). At the higher pressures (3Hg/9p)x Is nearly zero for this system. The experimental results are compared with the UNIFAC-2 prediction. Agreement is excellent for (butane + methanol) at 298.15 К and at both 5 and IS HPa, but deviations occur at higher temperatures Indicating that the temperature dependence is not correctly predicted by UNIFAC-2. For (propane -l- methanol) and (ethane + methanol) at 298.15 K, the experimental results are lower than the UNIFAC-2 prediction over the entire pressure range, but the agreement improves as the pressure increases. Figure 1 shows the extent of the agreement at 298.15 К between UNIFAC-2 and the experimental results id a function of pressure for the X - 0.5 mixture of each of the three systems. Some of the (methanol + ethane) measurements were made at pressure and temperature conditions where (fluid + fluid) phase equilibria is present. The phase diagram at 7.5 HPa has been constructed from the breaks in the Hg versus mole fraction curves. *• Figure 1. Graph as a function of pressure of the difference (AH§) between the excess enthalpy predicted from UNIFAC-2 and the experimental results. •. (C2H6 + CH3OH); X, (C3H8 + CH3OH); •. (C4H10 + CH3OH). The results are at 298.13 К and a mole fraction of 0.5. Those at 2.98 MPa are from earlier work in our laboratory.*'^ REFERENCES 1. J.T. Slpowska, R.C. Graham, B.J. Neely, J.B. Ott. and R.'H. Izatt, J. Chem. Thermodynamics 1989, 21, 1085. 2. H.E. Post, T.A. He Fall, J.J. Chrlstensen, and R.M. Izatt, J. Chem. Thermodynamics 1981, 3, 77. 3. T.A. HcFall. H.E.. Post, S.G. Collins, J.J. Chrlstensen, and R.M. Izatt, >U Chero. Thermodynamics 1981, 13, 41. 120 EXCESS ENTHALPIES AND PHASE EQUILIBRIA FOR ACETONITRILE WITH ETHANE, PROPANE, AND BUTANE J.T. Slpowska. J.B. Ott, and R.H. Izafct Department of Chemistry, Brlghao Young University, Provo, UT USA The heats of mixing of acetonltrlle with ethane, propane, and butane have been measured In the temperature range from 298.15 to 348.15 К and at pressures fron 5 to 15 HP*. (Liquid + liquid) phase separations occur In all three systems. The phase diagrams were constructed from the calorlmetrlc measurements. The aethod used to construct the diagrams as well as the Influence of the alkane size on the mlsclblllty with acetonltrlle will be discussed. 121 THERMODYNAMICS OF DILUTE AQUEOUS SURFACTANT SOLUTIONS: N- ALKYLPYRIDINIUM AND SUBSTITUTED PYRIDINIUM HALIDES T.P. McGinnis and EM. Woolley Department of Chemistry, Brigham Young University, Provo, Utah, USA 84602 Enthalpies of dilution have been measured for aqueous solutions of chloride and bromide cationic surfactants containing, the pyridinium group at temperatures from 283.15 to 343.15 K. Some osmotic coefficients were also determined at 328.15 K. Effects on the measured quantities of n-alkyl chain length, head group structure, surfactant concentration, and ionic strength will be discussed. A mass-action model that includes activity coefficients for all species was used to interpret the data. The model can adequately describe the experimental results. Thermodynamic parameters derived from application of the modal include changes in free energy, enthalpy, and heat capacity for formation of micelles, both at the usual standard state and at finite concentrations including the critical micelle concentration. Trends in both experimental and calculated quantities will be examined in order to try to understand the effects of surfactant structure, concentration, temperature, and solution ionic strength on the behavior of ionic surfactants in aqueous solution. 122 PARTIAL MOLAR HEAT CAPACITIES OF SOME N-ACETYL AMINO ACID AMIDES, SOME ЛГ-ACETYL PEPTIDE AMIDES AND TWO PEPTIDES AT 25°C. Gavin R. Hedwig and Julia F. Reading Department of Chemistry and Biochemistry, Massey University, Palmerston North, New Zealand Terence H. Lilley Biothermodynamics Laboratory, Department of Chemistry, The University, Sheffield S3 7HF, U.K. There is currently some interest in the heat capacities of amino acids and peptides in aqueous solution.. A considerable amount of this interest arises because of the relatively large number of studies, on protein containing systems.1 In such studies an important quantity which needs to be known is the heat capacity of the denatured protein as a function of temperature. It would be useful to have some means of obtaining an indirect assessment of the heat capacity of proteins, especially when they are in their denatured state and, given the range of protein types and the enormous variety of ways in which the amino acid subunits can assemble, a predictive scheme based on the amino acid residues present in any protein would ha -e considerable utility. The heat capacity of a given protein in aqueous solution can be estimated, at least to a first approximation, from a knowledge of its amino acid composition and from the group contributions of the amino acid side chains and the peptide backbone unit. The peptide group contribution has been assessed by combining heat capacity data for amino acids and peptides.2 For these solutes- however, the charged groups interfere with the solvation of the side chains and also with the intervening peptide groups. Hence, these solutes are not completely suitable model compounds for estimating group contributions. Two approaches that can be used to overcome the effect of the ionic groups are, either to use longer peptides, where the charged groups are far removed from the side chains of groups of interest, or to use as model compounds, derivatives that have no ionic groups present.3 This latter approach has been used in the present investigation. The results will be described of an investigation of the partial molar heat capacities, in water at 25°C, of some iV-acetylamides, of amino acids and peptides. The information obtained will be discussed using a group additivity approach and group contributions will be given. These differ, in some instances, and particularly that for the heat capacity of the peptide group, from those obtained in an earlier study. From a comparison of the parent amino acids and peptides with the amides it will be shown that there is a marked contribution to the heat capacities of the zwitterionic compounds from electrostatic sources. 1 P. L. Privalov, Adv. ProteinChem., 33 (1979) 167; P. L. Privalov and S. J. Gill, Adv. ProteinChem.. 39 (1988) 191. 2 С Jolicoeur and J. Boileau, ^nnad. J. Chem., 56 (1978) 2707. 3 G, M. Blackburn, T. H. Lilley, and E. Walmsley.J. C. S. Faraday Trans.. 1. 76 (3980) 915. l?7: ГПК ENTHALPY OF INTERACTION OF SOME ALKALI METAL CHLORIDES WITH SOME AMINO ACIDS M. Л. Gallardo , T. H. Lilluy. Helen biiicdell, S. Otin and A. J. Ward tHotlvrniodvnnmics L.ilmialory.Chemi-try Department, The University, S'lu'lIiddSS'/HI'ML 1С ;s. is well known that .salts con have marked effects on the stability of protein sinicures and that some electrolytes have a tendency to disrupt the structural '.•.liiHV if proteins, whereas other electrolytes show a propensity to stabilise or • !j(.h'№.; such structures. The molecular reasons for these phenomena are not well ii".'.\—sitood, but U is clear that electrostatically based approaches are inadequate to rvij'nin the 'ihservod effects since, for example, the small lithium ion is generally a i i-lciii prokin destabiiant and, as ihe alkali metal ion series is descended, there is a ..i.ir'cnry for stabilisation of protein structures to occur. In contrast, for the halide ми:'-, ''is fluoride ion is a protein stabiliser and the larger ions become increasingly i.t(ica"ious in disrupting macromolccular structural order. A broad qualitative .4"il -ir-! which is found is I hat the range of discrimination shown by the halide ions is much greater than that shown by the alkali metal cations. There is some .•viduncp which indicates Unit the major effects of ions on protein structures arise primarily from interactions occurring between the ions and the peptide groups on the protein backbone. It also seems reasonable that there should be significant contribution? from interactions between ions and other polar and ionic groups nrc-i-e'H on the mncromoleculc. However, and in contrast, there is opposing • :"id(!noe, which indicates that the discriminating effects of salts on proteins arise principally from the interaction of the ions with hydrophobic groups present in amino acid side chains. filobular proteins are, of course, rather complicated molecules and their iiiLcrnctionH with stilts must necessarily be both complex and multifarious and, will ••.IIKO, in a general sense, be environmentally mediated. Our general approach has i.i'!;!i to st.idy small molecules, which contain some of the features of proteins, in the houe 'hat some insight nt leapt into the more complex systems will be gleaned. In modi, o'.'ouv previous work in this area,' we have investigated systems in which the si do chains of the amino acid or peptide are apolar in nature. We continue this in the prosent work but also turn our attention to amino acids for which the side chains have a chemical functionality present. In particular, we consider the amino acids serine and threonine both of which have a hydioxyl function, and how these interact with the salts sodium chloride and potassium chloride. The entire experimental study which will be described, addresses the interactions by the use of calorimelry. V. K. G. 1'nvis, M. A. Cintlanlo, and Т. Н. Lilloy, Fluid Phase Equilibria, 57 (1990) 191. 124 EFFECT OF P-LACTOGLOBULIN ON THE REVERSIBILITY OF BOVIN a-LACTALBUMIN HEAT DENATURATION. A D.S.C. STUDY. P. RELKIN and B. LAUNAY ENSIA, Food Science Department 1, Avenue des Olympiades, 91305 MASSY-FRANCE. Temperature, enthalpy changes and reversibility of heat denaturation of p-lactoglobulin (p-LG), ct-lactalbumin (a-LA) . and mixtures (a-LA:p-LG) of these two globular whey proteins are determined by differential scanning calorimetry (D.S.C). The proteins are dispersed in distilled water (pH_6.5). Protein concentration and temperature varied from 2mM to 6mM and 5°C to 100eC, respectively. The reversibility of heat denaturation is determined by comparing the apparent enthalpy changes (AHapp) corresponding to "native" samples and to previuosly denatured ones, cooled to 5°C and then re-heated in calorimeter. For p-LG, second heating gives rise to an endothermic peak at the lowest protein concentration (_2mM) and at heating rates higher than 7.5°C/min and to a glass-like transition at the other protein concentrations ant at scanning rates up to 7.5eC/min (Fig. 1). R». 2 REVERSIBILITY OF ОН Н6 AT OENATURAT10N (3.5%. EMPTY REFERENCE PAN, COOLING FROM 120'C TO 10'C AT 200'C/min). (a), (b).(c): FIRST SCANNING AT WC/mln, 12.S'C/min and IS*C/mln. RESPECTIVELY. Mi №1, (el: SECOND SCANNING RUN AT 10'C/min. 12.5'C/min and IS*C/niin, RESPECTIVELY. (d) SECONO HEATING RUN AFTER FIRST SCANNING AT UP TO 7 .УС/min. 125 2 For a-LA in the holo-form (Ca+ +-linked) the "reversible two-state" model is relevant at concentrations up to 6mM . The thermodynamical parameters of denaturation are summarized in table 1. d T ДН ACp AS AG (°C) (kJ/mol) (kJ/mol) (J/mol) (kJ/mol) 58 320 4.7 968 25 165 474.5 23.6 Table 1. Thermodynamical parameters of a-LA heat denaturation. („5mM , holo-form, 10eC/min from 5°C to 100°C) • Heat stabilities of mixtures of a-LA and p-LG in various proportions is determined. In association with B-LG, a-LA heat denaturation becomes irreversible if the concentration ratio (a-LA:p-LG) is less than 1. Thermodynamical parameters are compared with those obtained at lower concentrations and other experimental results ( 1-6). REFERENCES 1. W.Pfeil. Biophys. Chem. 13(1981} 181-186. 2. Y. Hiraoka. T. Segawa, K. Kuwajima, S. Sugai and N. Murai. Biochem. and Biophys. Res. Comm. 95(1980)1098-1104. 3. K. Kuwajima, Y. Harushima and S. Sugai. Int. J. Peptide Protein Res. 27 (1986) 18-27. 4. P. Relkin and B. Launay. Food Hydrocolloids. 4 (1990) 19-32. 5. P. Relkin, J. C. Gimel and B. Launay. In XX-XXI Journees de Catorimetrie et Analyse Thermique, Clermont Ferrand. 14-17 Mai 1990, pp 33-40. 6. P. L. Privalov and N. N. Khechinashivili. J. Mol. Biol. 86 (1974) 665-684. 126 ENTHALPIES 0Г INTERACTION OF DIPEPTIDE-LIKE MODEL COMPOUNDS IN SEVERAL SOLVENTS. INFLUENCE OF CHIRALITY A.H.Sijpkes, G.Somsen Department of Chemistry, Vrije Universiteit, Amsterdam, The Netherlands Enthalpies of dilution of W-acetyl and N-acetyl-W"-methyl amides of several amino acids in various amidic solvents have been measured calorimetrically at 25 °C. The results were used to calculate a number of enthalpic interaction coefficients of these solutes using equations which are related to the McMillan-Mayer theory of solutions. Attention will be given to the values of the pair interaction coefficients in these three solvents, which are a measure of the energy of interaction between two solute molecules. Generally, the pair interaction coefficients are negative, the more the larger the alkyl groups in the solute molecules. The possible role of these solvents to be used as model environment for the inner parts of globular proteins will be discussed. Using the assumption that L,L-lnteractions are equal to D,D-interactions, enthalpic pair interaction coefficients of homotactic D,L-pair? and heterotactic L, L- and D,L-pairs of.peptides could be calculated. It appears that D,L-interactions are characterized by a significantly less exothermic interaction enthalpy than L, L-interactions. The results are interpreted by using a model for dimer formation in solution and compared with some results in water from literature. REFERENCES 1) A.H. Sijpkes, Thesis, Vrije Universiteit, Amsterdam, 1990. 2) Т.Н. Li1ley in, H.N. Jones (Ed.), Biochemical Thermodynamics, Elsevier, Amsterdam, 1986, Chapter 1. 3) D.C. Roberta, U.S. Bohacek, Int. J. Pept. Protein Res. 21 I19B3) 491. MULTIVARIATE CHEMOMETRIC PROCESSING OF GIBBS FUNCTION, ENTHALPY, ENTROPY AND RELATED QUANTITIES: A QUANTITATIVE APPROACH TO THE THERMODYNAMIC STUDY OF SOLUTION EQUILIBRIA. R. Aruga Department of Analytical Chemistry, University of Turin, via Giuria 5, 10125 Turin, Italy. .An increasing number of parameters are available in the thermo dynamic study of solution equilibria. Besides the usual triad: UG, AH, AS, some other quantities, such as molar volume (AV) , molar com pressibility (ДК) and expansibility (Да), have begun to enter into use in recent years. Some quantities are useful in the investiga- * ion of equilibria in non aqueous solvents, such as donor number, acceptor number etc. Finally,parameters referring to the species making part in the equilibrium are also available (e.g., the calcu lated hardness and softness of ions, proposed by Klopman, etc.). As concerns the treatment and the interpretation of experimen tal data, the usual univariate methods can prove to be inadequate in the presence of several variables, while, on the other hand, multi variate statistical methods' could be useful in such cases. Several matrices, each of them corresponding to about 60-80 protop-ligand and metal-ligand equilibria in water (or in mixed sol vents) and to 6-13 thermodynamic variables have been processed, in the present series of investigations, by various multivariate tech niques, such as hierarchical clustering, principal component analy sis,- non-linear mapping, Soft.Independent Modelling of Class Analogy (SIMCA), Bayesian analysis, multivariate feature selection. The el ectrostatic and non-electrostatic part of Gibbs function and enthal py were also included among the variables, in order to check their usefulness and practical significance. The conclusions which can be obtained by the use of the above cited techniques can be subdivided into the following groups: (i) study of the significance of thermodynamic and related quanti ties; (ii) study of the factors which determine the complex forma tion; (iii) evaluation of the information content of each variable? (iv) study of the properties and the structures of the complexes formed. It can be observed that, in general, multivariate techniques make more immediate and more quantitative the thermodynamic investi gation of solution equilibria, in comparison with the usual methods. It can also be said, in other words, that the former methods allow one to extract in a more complete way the information content of ex perimental data. 128 PREDICTION OF GALORIMETRIC PROPERTIES OF LIQUID MIXTURES BY THE NRTL AND UNIQUAC MODELS Y. DEMiREL, H. GECEGORMEZ and H.S. PAKSOY Faculty of Art and Science, University of Cukureva.Adana 01330,Turkey ABSTRACT Heats of mixing, hE, data are extremely valuable for testing solution models and understanding the effect of moleculer structure on thermodynamic properties of liquid mixtures tlj. In recent studies, the NRTL and UNIQUAC models were used in representing of hE and excess Gibbs energy, gE, data simultaneously [2,3]. Required temperature dependent parameters were estimated by using he and 9E data simultaneously and used in predicting heats of mixing and partial molar heats of mixing at infinite dilution Hi,[4]. Although the models are capable of correlating hE data for various kind of mixtures, type of data regressed it. parameter estimation plays important role in such capability due to empirical character of the models.Therefore, temperature dependent parameters, six and four for the NRTL and UNIQUAC models respectively, are restimated for 71 systems using only he data at more than one different isotherm.Temperature dependency of Che adjustable parameters of the models ia assumed as nonlinear. The models are later tested in predicting the calorimetric properties, such aa hE, excess heat E capacity c P,and AHt for which the experimental measurements are rare at desired temperatures. The values of heats of mixing at infinite dilution are finite but indeterminate. Hence the ' values of flHt were determined by graphical extrapolation of finite concentration data of hE. The values . of ДЙ1 correspond to the energy changes associated with interascton energies between unlike molecules of mixtures. Experimental values ut he and c»e and extrapolated values of AHi were compared with the predicted values. Discrepancies in the extrapolations are estimated as percentage uncertainties [4]. Performance of the models are mainly satisfactory except for those of strongly associating mixtures. [1] S.Murakami and R.Fujishiro,Bull.Chem.Soc.Jpn.,40(1967)1784. (2) Y.Demirel and H.GecegSrmez,Can.J.Chem.Eng.,67(1989)455, [3] Y.Demirel and H.Gacegc-rmez, Fluid Phase Equil.,in press (41 Y.Demirel,Thermochimica Acta,170(1990)197. 129 COMPLEX PERMITTIVITY AND DIELECTRIC RELAXATION IN AQUEOUS SOLUTIONS OF TETRAETHYLAMMONIUM CHLORIDE M.Kleebauer*, R.Buchner*, S.Levanova**, H.Hetzenauer*, and J.Barthel* * Institut fur Physikalische ursd Theoretische Chemie, Universitat Regensburg, Germany. ** Polytechnic Insitute, Kuibyschew, USSR. • The dehydrochlorination of halogenated aliphatic hydrocarbon compounds with aque ous alkali hydroxide solutions is a classical example for /^-elimination reactions and is used in the technical synthesis of olefin and dien compounds. These hetero-phase processes are characterized by small rate constants and their applicability is limited by the low solubility of the organic educt in the water phase. These limitations can be circumvented with the help of phase transfer catalysts, e.g. tetraalkylammonium salts. The mechanism of ion transport in phase transfer catalysis is much discussed in the literature, but only few quantitative data are available. It is known that, besides transport through the phase boundary, kinetics and thermodynamics of ion associa tion in both phases play an important role. Dielectric relaxation experiments provide a powerful! tool to study fast processes in solutions. In this contribution we present first results of a systematic investigation of the complex permittivity of tetraalkylammonium salts relevant for phase transfer catalysis in aqueous and non-aqueous solvents. The complex permittivity spectra of tetraethylammonium chloride in water, obtained at 25°C in the frequency range 0.3 < f/GHz < 89, exhibit a strong increase of the relaxation time of the solvent from 8.3 ps in pure water to 12.6 ps in a 1.2 M solution. This suggests strong interactions'between Et*N+ and water in the sense of hydrophobic interactions, since it is known that CI" is only weakly solvated. The data reveal that ion pairing is not significant in these systems. 130 yO!b.i:\.'.liio A" •) i)i:.UTHlfIil''OR-.IAJ.iIDS A.r'.VOil'.-o' JV, n.I..AU3TAFIII Department of General and Inorganic Che mistry,Mendeleev Institute of Chemical Technology, Miuaskaya pi.,9, Moscow 125820, USSR According to the Solubility Data Project of the IUPAC Commi ssion on Solubility Data the solubilities of alkali metal sul phates were investigated systematically . Constancy of solubi lity values in approach to the equilibrium state on the part of both the non saturated and over-saturated solutions proved that equilibrium had been achived. The next table contains solubilities( C'10 , moLdm--*) in the various systems, including formamide (PA) and dimethyl- formamide (ШР) : 293 К ,2?8 К зоз к 313 К 323 К Li2S04 - PA 4.13 4.97 5.08 5.26 5.76 Na2S04 -PA 5.68 5.36 4.23 з.зо 2.62 K2S04 - PA 2.51 3.61 5.13 6.13 6.52 Hb2so4 - PA 7.42 6.44 5.94 7.61 7.93 Li2S04 - .V.iPA 3.31 3.18 Kaj,S04 - D:.1PA 2.07 2.43 4.04 3.70 2.97 I:?:JO4 - .i.,.'.\ Z • !''Г Г:.о4 3.o4 3.74 3.67 х иЪ?:юл - •/.;;••,; '1.30 4.0!' 5.02 4.69 4.51 : Cr.2oC4 - i.... ч.4 5 3.5? 3.27 3.13 2.78 131 EXCESS MOLAR ENTHALPIES OF MIXTURES CONTAINING TP.I-H-BUTYLPHOSPHATE. P.A.Erastov, V.A.Petrunin, A.V.Tarasov, N. I,Fan talcva State Union Reserch Institute of Organic Chemistry and Chemical Engeneering, Moscow, 111024 U.S.S.R. Excess molar enthalpies were measured with a Piker flow micrqcalorimeter ( Setaram, France ). Before measurements, the performance of the calorimeter was checked by measuring H£ of test mixtures: ( ethanol+hexane ) at 298.15 K. Agreement with literature data was within 1 per cent. TBP was. fractionally distilled under reduced pressure. The purity was checked by chromatography.The water content of TBP was determined less than 0.05 mol per cent. No others impurities were observed. The solvents were purified by methods described In reference The equation: HV(J'mol"1 ) = x(1-x) В A. (1-Sx)1 (1 ) m о i was fitted to the experimental values for all solvents. The parameters A., obtained by least-squares method, are shown in table 1. For the systems TBP + chloroform or benzene or CC1. negative enthalpies of mixing were observed. In this case exothermic contribution arising from newly formed hydrogen bonds with proton acceptor phosphoryl oxygen ( from CHC1,,). strong interaction between о phosphoryl oxygen and IT -electrons of benzene and donor - acceptor . complexation ( for CC1.) was larger than endoeffects of breaking the bonds in self - associated liquids. Excess molar enthalpies of mixing of TBP with ethanol, acetone or hexane are endothermic. For these mixtures the exothermic contribution from newly formed bonds was smaller than the endothermic one from the disruption of the bonds in the self - associated liquids. Our results for TBP + hexane, + benzene, + CC1, were in reasonable agreement with values, reported earlier ' '. tiEFERENCES 1) H.K.Jones, B.C.Lu, J.Chem.Eng.Data 1966,11,489. 2) B.Kiel, Laboratory Methods of Organic Chemistry,M.Mir,1966. 3) L.Tslmerling, A.S.Kertes, J.Chem.Thermodynamics 1974,6,411. 1) Yu.A.Afanas'ev, A.V.Nlkolaev. T.I.Koroleva, Radiokhimiya 1966.8.696.. Jc2 Tab! 1. Coefficients A., of equation (1). A1 A2 A3 A4 A5 xTBP+(1-X)CHCl3 -3912 -1206 -288 -125 -330 -839 xTBP+(1-x)CgH50H 91.38 70.6 51.4 6.04 20.4 22.9 xTBP+(1-xMCH3)2CO 165.0 112 60.8 65.1 12.4 102 xTBP+(i-x)CCl. . -772 -195 -174 -163 -252 -378 4 xTBP+(1-x)C.H, -193 -85.8 -56 -111 . -17 -103 о о xTBP+(1-x)C_H. . 680.0 285 126 199 189 123 5 14 1 IS2 ENTHALPIES OF SOLVATION AND COMPOSITION OF SOLVATE SHELL OP THE IONBS IN MIXTURES FORMAMIDE-WATER AKD DIMETHYLFORMAMIDE- VATEK. A.F.Vorob'ev, A.S.Monayenkova, T.D.Quanishbayev, L.A.Tiphlova, W.A.Frolova. . Moscow Mendeleev Chemical Technological Institute, USSR Moscow State University, DSSS. Enthalpies of solution of LiBr in the mixtures formatnide (FA)-water and NaZSr in the mixtures dimethyll'ormamide (DMFA)- water have been measured at 298,15 К in hermetic moved calori meter (the thermometric sensitivity - 2,5 x 10' Enthalpies of solution of bromides at infinite dilution have been calculated using Debye-Hiickel equation in second ap- roximation. From the enthalpies of solution, using the enthal pies of solution of the other bromides£1,2,3], we have calcu lated . H solvation of the whole bromides of the alkaly metals. We have calculated also the solvent composition shell of iones bromides in FA-vater and DNFA-water. The changes in obtained values, depending on solvent compo sition, nature of electrolytes and solvent have been discussed. R E I? E В Б К О 2 S 1. T.D.Quanishbayev, A.S.Monayenkova, A.F.Vorob'ev, J.Phys. Chem.(T!uss). 63 И989) 28*7- 2. A.S.Monayenkova, T.D.Quanishbayev, W.A.Frolova, A.F.Vorob'ev, 7I-A11 Union Uonference "The thermodynamic of organic com pounds", Minsk (1990) 191 3. A.S.Monayenkova, T.D.Quanishbayev, A.F.Vorob'ev, Rep.Inv. Mosoow Mendeleev Ohem.-Tech.Inst. No.15rf (1989). KM UNUSUAL PROPERTIES OP ИОН-ELKCTROLYTE SOLUTIONS IP THE VICINITY, OF SOLVENT CRITICAL 1'OINT A.M.Rozen All Union Sci.Res.Inst, of Inorganic Materials. 123060, Moscow, Rogov st. 5, USSR The most surprising feature of critical dilute solutions lies in the fact that the limiting values of some thermodynamic values, vie., partial mole volume, enthalpy and enthropy, differ on approaching the critical point irjdifferent ways. This is rela ted to the {"&V/X> \')fderivative becoming nil at the critical point. Remember that the partial mole volume of a solvent is equal to Since at the critical point the derivative Ct) P/"fe K)«A has a finite value, the limiting value of V\ depends on the law by which (^ P/"? V)t becomes nil on the particular way. This law can be found by tlie mathematical description of the gas properties in the near-critical region £l, 2 j; which is an expansion in series over . the powers W.V-Vo and Т-Тсл: , дс дР 1 AN' *A'*T- CBN Ж^-фУ/Г (e) where UP-P-Pct , ДТ-T-Tti , £iV-V-Vci ', tj/ 3; A,A' .B.B* and С are values of the corresponding derivatives at the solvent critical point. Using equation (2) ono can find that there are"linear ways" 'along which Cap/fc V)r is linearly dependent on the mole fraction of a solute *—o/s»/\ ,^-»/- This is a critical curve (CC) for which К--А2/ЙТ and the isotherm-isochore (K1I) for which К—В. It can be seen from fig. 1 that the experiment j.3] validates the theoretical dependence (3). But taking, account of (3) it follows from (1) that the limiting value of V.| at H->»-0 does not coincide with the mole volume of a pure solvent (Vj ) but i3 eqjjal to -CL^V, r= V" ч-Д/к (4) Iv -re 'ЧчДгЦ m дм Ьч н Fig.1. Validation 0Г equition (3) (solvent is S.IS 0,1 SF* .solute-propone (1) Pig.2. Valid-ation- of equat and CO-, (2,;0 ions (6);C02 (solvent)- ethane system T)'ia, tiie dependence Y\ (K) at N-»0 have a discontinuity, the amount of " jump S\\ »Л/К depends on the way ("K" values)L?] When movim- along the critical curve (CC) and the critical iso- therm-iaochon; (KID 135 J For the SFd (solvent)-C02 system (Л-63.5, В -0.27,B«3.4x103) one finds §ЧЛ .«."-430 om3/mole, and d* %,«&"-240 cm /mole; the data [4,5,] confirm the theory. But along with the available discontinui ties the very fact of the negative values of % • i.e. a decrease in the system volume on solvent adding is also interesting. However, together with the linear non-linear ways also exist, when (Ъ 2P> VlfN, where m< 1. e.g., along the critical isotherra- iaobar when it follows from (2) and (1) . _.(£--tJ/£ u ,У£ (ЪР/ЫГЪ ~ tf ' j V1 -v/+aw **•-» fc i f2~ */ «J i.e., the anomaly disappears, there is no discontinuity, the li-. mitirig value of V^ is V4 . However, the theory predicts"that at i'v'-^О "ЪУн/йМу -гчхЭ (as distinct from usual dilute solutions, when (pV/c> N)-'N--»-0). It can be seen from fig.2 the experiment invalidates the theory. The partial mole enthalpy and enthropy also experience discon tinuities at H-*0; the magnitude of the jump is equal to 5hj«A'T rpt. = rc t-A/ads'j P„c = Pc +(A -4 'в /*№) Pig.3. Phase equilibria for SfV (solvent)-C02 system; С - experiment, x - calculated REFERENCES 1. A.M.Rozen. JETP 56,(1969),914:Soviet Physics JETP,24(1969),494. 2. A.M.Rosen. Zhurn.fiz.khim.50,(1976),1381. 3. L.A.Makarevich.O.N.Sokolova.Dokl.AN SSSR,217,(1974),626. 4. I.R.Krichevsky.L.A.Makarevich.Dokl.AN SSSR,175,(1967),117. 5- I.R.Krichevsky,Thermodynamics of critical infinetely diluted solution, "Khijciya" , Mowcow, 1975» 6. M.E.Khazanova,u.E.Sominskaya.Zhurn.Phys.Khiro-,45(1971),2625. I?G SOLVATION THERMODYNAMICS OF COMPONENTS IN NON-ELECTROLYTE SOLUTIONS L. L. Gurariy Vitamin Institute, Moscow, 117820 GSP-7, USSR The present work summarizes the data on calculation and rediction of the thermodynamic functions of solvation in §inary systems of different classes: alkane - aromatic hydrocarbon CI), polar solvent - aromatic hydrocarbon С2) and polar solvent - water C3). Solvation thermodynamic functions were considered as the transfer functions of one mole of substance from the standard state of the ideal gas at a temperature T and pressure of 1 atmosphere into a solution. On the basis of our and published data on excess thermodynamic properties of non-electrolyte solutions the quantities of solvation enthalpies CH |y ) and entropies CS|V ) of the components of systems 1-3 were obtained for a wide range of concentrations and temperatures. It was established the presence of linear correlation s|y= A + В h~v which does not change in the entire concentration range for all the systems. The coefficients A and В are practically constant for all temperatures at the fixed composition. The A and В dependencies on concentration are complex, and differ considerably for aqueous and non-aqueous systems. The results obtained were interpreted from the point of view of different types of intermolecular interactions by the formation of solutions. I?7 HEAT CAPACITIES OF ASSOCIATED ELECTROLYTES IN AOUEOUS SOLUTION. S.I.Drakln,V.A.Hihailov,О.V.Popova Hoakow Chemlcel-Technology Institute named after 0.I.Mendeleev, Moskow Institute Of Fine Chemical Technology named after И.V.LoMonosov, Hoakow A-190, USSR The Method for obtaining of standard partial utolal heat capa cities С _ of electrolytes in' aqueous solutions has been derived. This aethod la baaed on aaauaptlon that the apparent aolal heat capacities Ф dependence froa the Molality м has been explained by change of Ion aasociatlon under « < 1 . In this case part of undlsaociated apeciea (Molecules or Ion pairs) la lncreaaed with Molality increase. From thla we can write ф .a 5* • C1 -«О Ф.„ , С р2 ж a where - the degree of dissociation, *.B~ the apparent aolal heat capacitlea of undiasoclated forma of electrolytes AB type. Using our assumption and the Oatvald law for constant of dissociation 1 - « where t^ - the activity coefficient of the lone, after transfor mation, we have obtained the expression for С_. Applying this —о P* aethod yields the values of С_ for symmetrical electrolytea. In this caae the concentration dependences of Ф critically aelected from literature have been uaed. We have assumed that Ф „ is approximately equal heat capacity of crystal aalt С (cryat). Uncertainty of С__ calculation due to approximate values of Фдв is not greater than 0.01«Ф ,where *ФЖИ- uncertainty of Ф._. A criterion that Must be Met Is the addltivity of the standard partial aolal heat capacity values of the cations and anions to yield the values for the electrolytes. Conformity with the additlvity rule is within 5 J К mol . Calculated values of a and К ox electrolytes in aqueous solutions is near to values obtained by electrochemical methods. 138 THE PREDICTION OF SALT SOLUBILITIES IN THE SYSTEM Na.K.Mg/YCl.SO - -H20 AT ELEVATED TEMPERATURES BASED ON THE PITZER MODEL. S.V.Petrenko*,v.M.valyashko*.G.Ziegenbalg** * Kurnakov Institute of General and Inorganic Chemistry, Academy of Sciences, Moscow, USSR **Frelbei'g Bergakademie, Freiberg, Germany The recently developed Pitzer formalism has provided a very valuable tool -For the analysis, consistency and prediction o-f the thermodynamic properties of concentrated electrolyte solutions and solubility equilibria in the multicomponent aqueous systems. The Pitzer model has already used to describe all solubility equilibria in the system Na,K.Mg//Cl.S04-H20 up to 50 С [l-3]. Me continued such description of salt solubility behavior in this system up to J40 C. Accurate solubility prediction in the frame of Pitzer model can be made if the values of six types of Pitzer parameters and chemical potentials of solid phases are known. The choice of the binary Pitzer parameters have been done from the set of literature values by the comparison of the solubilities calculated using these values with the best experimental data of the binary systems. Nine ternary Pitzer parameters were adjusted to- the solubility measurements from ternary and quaternary systems. The smooth temperature dependencies of the Pitzer parameters up to 150 С were obtained. Thermodynamic data for the eight double salts were determined from the solubility data to complete the literature data [4) for other 17 solid phases. Using these consistent : 'lermodynamic data and Pitzer equations the complete solubility diagram of quinary seawater system was evaluated up to 100 С and the NaCl crystallisation volume was extended up to 140 С The comparison of the predicted values of salt solubility in quaternary and quinary systems with experimental data shows good agreement. REFERENCES 1) Harvie C.E..Wears J.H. Beochim. et Cosmochim. Acta 44 (1980) 9B1 2) Shestakov Ч.Е. Ph.D. Leningrad 1985 3) Korobkova E.V. Ph.D. Leningrad 1988 4) Pabalan R.T.Pitzer K.S. rnnchim. et Cosmochim. Acta 51 (1987) 2429 139 STUDY OF IRON(III) CHLORIDE COORDINATION INTERACTION WITH ORGANIC LIGANDS BY TITRATION CALORIMETRY A.tt.Fedotov, E.S.Isaeva, I.P.Goldstein, V.V.Smirnov T.N.Rostovschikova Karpov Institute Of Physical Chemistry, Moscow, USSR • In order to determine the composititon and evaluate stability of iron(III) chloride complexes, important in certain catalytic processes of organic synthesis, its interaction with some organic Uganda (L) in methylene chloride was studied, L being dibuthyl- ether, diethylsulfide, triethylamine, ethyleneglycol, and also triethylbuthylammonium chloride (R«NC1).Investigation was carried out at 298°K by calorimetric titration of FeCls solutions in concentration 1-4 «Ю-3 mol/l by solutions of L. Stoichiometry and enthalpy changes of reactions (UHr ) were determined. In case of monodentate, nonassociating n-donore of electrons (BuzO, Et2S, EtsN), calorimetric titration curves show distinct equivalence points at I> and FeCla concentration ratio equal 1:2. Further addition of titrant causes slight heat effects due to for mation of complexes with higher content of L. Evidently, in this case ionic forms of comlexes fnlMFeCle]* QTeCleJ- are obtained. Enthalpies of these complexes formation (at n=l), depending of L, increase in succession: ВигОСДНг =15+2 kJ/mol) < EtaS( ДН* =20+2 kj/mol) << << EtaN( ДНг = 220 + 20 kJ/mol) 'Reliability of conclusion, that iron(III) chloride in above- mentioned systems forms anion [FeCl-»]- is confirmed by the fact, that, according to calorimetric titration data, stoichiometry of its interaction with tetraalkylammonium chloride is 1;1> e.g.this reaction follows next scheme: R«NC1 + FeCls 5=? [H4NJ*fFeC^J- СЛНх- = 100 + lOkJ/mol). In contrast to this reaction, coordination interaction of iron(IIf) with ether,sulfide and amine is possible only by formation of complex cation [ph-FeClz]* , what explains observed stoichiometry of complexes. In case of ethyleneglycol, calorimetric titration curve is smooth and does not show distinct equivalence points, what indi cates on the formation of several iron(III) chloride complexes with oligomers of alcohol, which are associated through intermo- lecular H-bonda {. . .H0-(CHz)z-0. . .Jn . 140 THERMODYNAMICS OF SPARINGLY SOLUBLE ELECTR0L1TES IN NONAQUEOUS SOLVENTS E. F. Ivanova, LA. Rojas, N. G. Gegechkorl, A. N. Nlcolaychuc Dept. Of Inoiganic Chemistry, Faculty of Chemistry, Kharkov State University, Kharkov 77, USSR. The solubility product of electrolytes is one of the most important characteristics of electrolyte-solution systems and it is determined by the nature of components and the temperature, PS-л ±-{S+if±f "So'' (S+ - the solubility), a+-So is the activity of saturated solution of sparingly soluble electrolytes. The value S+ is determined experimentally. The value tf+ may be calculated according to Debye-Huckell theory under the condition that S+ does not exceed the concentration of Debye region. Often the value S+ is higher than Debye concentration especially in nonaqueous solvents. It makes impossible the use of an accurate theory for the Y+ calculations. Thus, for the determination of S-S+Tf+ we used the influence of the ionic strength of the solution (I) on the sparingly soluble salt solubility.. If the added electrolyte has no common ions with the sparingly soluble salt, then takes place the ecuation S+Jf+-S'+X' + in which index (') refers to saturated sparingly soluble salt solution in presence of added electrolyte. Thus lg S*+-lg S+ + lg7f+ - lg2f'+-lg So-lg8' + For lgtf'i is possible to use the theoretical Debye expression lg }f'+--AVT or the semlempirlcal expression lgif'+— AVT+KI. After transformations it is possible to get lg S'+-lg So+AVT(lf I—0) then lg S'+-lg So) or y-lg S*+ - AVT-lg So+KI. For the dependence y-f(I) the coefficient К may be equal (in the finet approximation) to the product ABa, in which В is the theoretical coefficient from the Debye Huckel ecuation lglf*+- -AVT/(l+BaVT)—AVT+ABaI-..я -Atff+KI From the dependence y-lg So+KI it is possible to evaluate the distance of maximum approach (a) of ions. We have determined SP, So, a for the solutions of KC10, in methanole, LiCl, NaCl, KC1, RbCl, CsCl in acetonitrile, CsCl in ethylendlamine. It was determined that in most cases din a/dT-0. The values of a depend on the nature of solvents salts and temperature. 141 THERMODYNAMICS OF THE PROCESSES OF LOW TEMPERATURE ASSOCIATION OF MOLECULES IN AQUEOUS POLVOL SOLUTIONS Osetsky A.I.,Alexandrov J.6..Bidny S.J.,Gurina Т.Н. 'nstitute for Problems of Cryobiology and Cryomedicine, Kharkov The phenomenon of temperature association of molecules in glycerol and polyethylene oxide aqueous solutions was studied by microealorimetry, microvolumetric tensodilatometry and thermoplastic deformation techniques. The kinetics of the water crystallisation accompanying this process was studied in a detail.The assymetry of this phenomenon relatively to the sign of temperature change has been demonstrated! the rate of molecule association during solution cooling is considerably lower than that during r«warming in the same temperature range.The observed effect of asymmetry is explained from a principally new point of view, taking into consideration the effect of medium viscosity on the activation energy, controlling fluctuational linking of polyol molecules. Complete diagrams of the states of aqueous polyoJ solutions has been obtained in a wide temperature range down to temperatures of glasss formation taking into account the observed peculiarities of polyol molecules association. The effect of low-temperature association of polyol molecules on biological system survival has been analized in those cases when polyol aqueous solution are used as cryoprotectants.lt is demonstrated that the effect of molecule association together with accompanying processes of water crystallization are the main damaging factors for biological systems cooled with the purpose of cryopreservation.Possible ways of reducing the damaging effect of this factor in various cryobioJ.ogic.al technologies are discussed. 142 ЮТ-TEMPERATORE CAbORIMETRY OP SUGAH6 AQUEOUS ВОШХОГО. E.O.Davldova, r.A.Mlkhalllk Institute or engineering Thermophyaies, Ukrainian BaB Academy of acienoee, Kiev, OSSH T.T.Hank Department of natural Dispersion Systeas, A.y.ao- gatsky rhysleoehenioal Institute, Ukrainian SBR Academy of Sciences, Kiev, TJMiR. The solvent alone ie known to be readily crys tallised when aqueous solutions of sugars are rapidly cooled while the organic coaponent prevents a oertain amount of water as a supersaturated solution from being frosen. Here the unfrocen water portion la usually regar ded as being hydrogen bonded to active centres of dis solved substance. low-temperature scanning calirimetry was used to uantitively assess the water fraction composition in ao- Jutlona.~ This resulted in sugar hydration curves, with the hydration nuaber being a ratio of aole nuaber of un frozen water to the nuaber of dissolved substance aoles* Said ratio is represented as a funotioQ of dissolved substance aole fraction in initial solutions» The investl- atione have shown that the hydration curves do not diff fer ouch in behaviour despite the fact that there is a substantial difference in amount of hydroxyl groups In saccharose molecule and those in molecules of monosaccha rides under study (see figure below)? 6 S SO 12 Ц У6 Cj mole fraction The hydration nuaber for saccharose (•), glucose (+), fructose (A) as a function of solution concentration. I4C- The extrapolation of hydration curves to abscissa axis in the plot of frozen water versus total moisture content results In Halting (coordination) hydration numbers such as 5 * 0,5 for saccharose, * + 0,5 for glucose and fructose. TEe obtained coordination numbers of hydration for bexoses are correlated with the number of equatorial OH - groups of the most possible conformers of these sub stances in solutions. There is no such a correlation for saccharose. This experimental fact .can only be acoounted for by assumption that assoeiates of saccharose molecules are formed in the eolution. This does not rule out the fact- that both Intramolecular and lntermoleoular hydrogen bonds can be formed as well as intermolecular interac tion can occur where there are hydrophobic regions of glycoside residues." 144 THE ENTHALPIES OF SOLVATATION OF TRETTIUTILHYDROPEROX IDE AND JWMETHYl VINILFTMYNYLMETHYLHYDROFEROXIDE IN ACTONE AND BENZENE. Y.A.Raevsky, V.N.Bibrivny, O.E.Chekan. Uept.of Physical Chemistry ,Fal:ul ty Technology of Organic Substances, L.vo4' Pol i techni cal Institute,Lvov,290646, ussrt. The use of hydroperoxide monomers in the process of polimeric materials synthesis ensured л modification of the polymeric mat rix and the possibility to vary th<» properties of the synthesised substances. The? development of a quideri eynther.i -з of hydroperoxide monomers requires fcrmwlr-drj e of fitechiometry and eqilibrium of the complexes formed. These values яге determined for tretbutilhydro peroxide (TBH) and dymethylvinilethynylmethylhydroperoxtde VEH ACETONE VEH - BENZENE •AH0 9.7S ?5.5 И9 249.8 20. 3S 212.8 431.5 32.95 311.5 IS. S430 540.3 43.96 1288.0 20.25 493.8 50.31 1386.0 33.31 644.3 55. 14 1И47.0 50.88 557.6 67.02 105.S 66.49 244.4 80. 90 77.06 91. 13 It? 89.01 TTIH - ACt-TONE TBH - BENZENE 4.45 19.3 4.26 - 294.4 9.41 34.01 10. 18 - 525.4 19.45 54.1 21.04 374 -?-*. ->-> 148.2 33.05 470 49187 'X39.9 49. 502 58 1? 261.3 67. 484 Ы- . 29 282. "3 73. 10 262 "79.2'» 66. 1 80.91 116 89.0"09" 37. Я 91.75 The pxtremums on the ДН, =f(X) curves in indicative of the presnnce of solvate cample* VEH - ACETONE, TBH - ACETONE and VEH - BENZENb. with a rativ 1:1,2:1,1:2 respectively. ИГ: SOME PROBLEMS OP TIIERMOD^IAJ.flCS OP SOLUTIONS ON THE BASIS OP N-P,ffiTKYbFYRROLIDMTE V.A.Vasilyov,A.N.Novikov,5.A.Khorishlco Mendeleev Cheraico-technological Institute, Branch in Novo moskovsk, Novomoskovsk, 301670, USSR. The actuality of investigation of non-aqueous solutions was caused by their wide utilization in industry, science and engineering. The solvent N-methylpyrrolidone chosen as the object of investigation is widely used in practice. However the data 'of its properties are limited. Moreover thermodynamic properties are of special interest and it defined the tasks of work: we have experimentally investigated heat capacity and volumetric proper ties of solutions on the basis of H-methylpyrrolidone (MP) and also the constants of electrolytic dissociation of dissolved substances. In order to study the influence of chemical nature of dis solved substances on thermodynamic properties the solutions in MP. were investigated: a) iodides of alkaline metals (Mel)', being the solutions of non-associated electrolytes (according to the data about electrical conductivity of Mel in MP /1/)s b) aromatic hydrocarbons (AH), being the solutions of non- electrolytes; c) benzenecarboxylic acida (BCA), being the solutions of associated electrolytes .(on the basis of measured by us the constants of dissociation BCA in MP). It was established that the differences in the character of dissociation of all three groups of substancec are reflected on concentration dependences of heat capacity and volumetric pro perties At the came time the gener.il for all studied ::ubctanees is the additivity of contributions of separate constituent;: (ions, functional groupo) iii "auucKxy" value of the property - standard partial mole heat capacity Bp, and btnnda.i'd par tin! mole volume 9| of a dissolved substance. For the solutions of non-associated electrolytes in "P the scale of ion constituents CS, nnd Vft was proponec and Grounded and usinc this зса1е the valueо CS cftd V? of ion;; in MP at 298,13 К were calculated: I" Li+ Na+ K* Rh' **pi' J(nole-K)~1 47 8 18 23 3P 54 V^, enAnole-1 24,2 3,6 3,2 11,2 15,1 21,3 On the basis of the data about Cft and Vf according to the equations proposed in work /2/ coordinative numbers of ions (a.) in MP were calculated: for ions Rb and I" n = 6, for ion IT n = 5. For solutions of BCA and AH in J.1P the contributions of separate fragments of molecules of dissolved substances into the Мб values v| and Cg> for BCA in MP and into the values 9? for AH iJ-n M*"P* were calculated— ",cuiaJ— '-: -C6H5 -H -C00H -CH- -CH2- £ , cm-mol3 e -1 73.2 13,2 27,5 29,8 16,7 1 6C, J(mole-K)" 120 80 119 "She values 6 and 6 can be uaed for calculation MJ and 5g, of organic compounds in MP at 293,15 K, when direct determination of these values is impossible or difficult. ni3Fr,RBNCK3 1) Dyke M.n.,Senro P.G.,Popov A.T. J.Phya.Chera. 71 (1967) 4140. 2) Vflnllyov V.A. Theoin T)oc. nhem. Sci. 1980. V. 1. 364. 147 THE THERMOCHEMISTRY OF AQUEOUS SOLUTIONS OF NATRIUM SULFITE, PYRO- SULFITE AND THIOSULPHATE. L. N. Parfenova,G.M.Pol torat5key,K.B.Bogolitsyn Institute of the North Ecology Problems,At-changelsk,USSR By calorimetry method the processes, observed during for mation of sulfite, pyrosulfite,thiosulphate natrium solutions have been studied. To carry out the experiment differential mic- rocalarineter and liquid calorimeter with isothermal envelope were used. Bidistilled water was applied as a solvent. The stady has been realized at 298 K. Tt is known, that rapid processes (solution,ion-molecular reactions) and slow processes (oxidation-reduction reactions) both proceed during formation of studied solutions. The attemps of other reseachers to suppress accompanied phenomenons when de terminating solution enthalpies are the sourses of the mistakes. We carried out thermochemical measurings not suppressing, but counting up a contribution of this interactions to common effect. Using ballistic curves integral enthalpy kinetic curves have been received. To calculate the oxidation enthalpy changes during the experiment integral enthalpy kinetic curves were di vided into two parts in conformity with a character of realizing processes. For corresponding to oxidation—reduction plot heat- discharge rate constants have been computed. Taking into account this constants the oxidation enthalpy changes dependence on the time of experiment has been received. Using the values of enthal py changes for the moment of reaction finishing and the values of current enthalpy changes the reaction rate constants have been calculated. It is shown that these constants depend on the initial concentration of the oxidized substances. The concentration enthalpy changes, constants and degrees of natrium sulfite hydrolisis have been received from the thermo- data. The extrapolation of integral enthalpies of solution from that zone of concentration, where effect of the ion-molecular in teractions are practically negligible, to zero concentration led to the following values of лH0 ,kJ/«ral: JlfyjiO^ :-i3,4+0,1;JK}<&0£: 17,2+0,ZijyQg^Oj-SHjfl :45,6+0,2.These values are in satisfactory agreement with Vanderzee data. The concentration formation enthal pies of studies compaunds solution have been calculated using con centration solutions enthalpies and enthalpies of formation of so lid substances. 1) Vanderzee C.E., Noll L.A., J.Chem.Thermodynamics. 19(1987)417. 1415 DETERMINATION OF ENTHALPIES OP INTERMUSCULAR AND ION-MOLECULAR BOND FORMATION IN SOLUTIONS BY IR SPECTROSCOPY METHODS I.S. Perelygln Department of Physics, Aviation Institute, 450000, Ufa, USSR The values of enthalpies of the molecular and salt solva tion, found by the oalorlmetry method, characterize summary ef fects of dissolution, conditioned both by the break of lnter-mo- leoular bonds In the solvent during the Intrusion of the elements of the dissolving substance into it, and by the formation of new intermoleoular and ion-molecular bonds; as for the applied methods of division of experimentally found summary values into molecular or ion components they are rather relative. The use of IR spectroscopy methods in the investigation of the molecular structure of the solutions conditions new possibili ties of determining the enthalpies of internolecular and ion-mole cular bond formation. For determining the values of AH quantities of lntemolecu lar bonds the temperature dependence of equilibrium constants of the appropriate reactions is widely used provided that the set of possible molecular forms is limited and there is sufficiently clear division of the absorption bands of free and bounded mole cules. In this case the influence of the medium on experimentally determined values of AH quantities, conditioned by specific In teractions of the molecules forming the bond under investigation with the solvent molecules, may be taken into account. In prin ciple the method is irreproachable but it is extremely labour-con suming and it makes high demands of the accuracy of the spectro photometry measurements. The errors of determining дН by this method are within 0,4-2 kj/mole. Another method of determining the enthalpies of mtermolecu- lar bond formation is based on using correlations between &H and the quantities of the relative shifts or increases of the integral intensities of the absorption bands under the influence of the bonds formed. The advantages of this method consist in Its univer sality and simplicity and in the possibility of determining the en thalpies in non-balanced systems as well when thermodynamlcal me thods are in principle unacceptable. Irrespective of the peculiar Titles of the molecular radical structure or even the nature of the active group the values of AH may be determined with the er ror not exceeding 4 kj/mole and within the rows of combinations of the same class with a constant partner as 0,4-2,0 kj/mole. Determined experimentally the identity of manifestations in the vibrational spectra of intermolecular and ion-molecular bonds make It possible to use correlations mentioned above for determi ning the enthalpies of bond formation of the anions with the mole cules of proton-donor solvents and of the oatlons with eleotron- donor molecules of the aprotlc solvents as well. As for determi ning the enthalpies of formation of ion-molecular bonds by inves tigating temperature dependencies of the absorption band intensi ty relations of free and bounded with an ion molecules of the sol vent it seems to be impossible because ion solvates retain their composition unchanged In a wide temperature range; and the tempe rature variation of the solution oranges only the degree of dis sociation of the dissolved salts and therefore the concentration of the ion solvates. K.« INVESTIGATION OF CHEMICAL EQUILIBRIUM IN THE SYSTEMS CONTAINING ASSOCIATED COMPONENTS. S. P. Verevkin, A. K. Prokofiev, I. B. Kashkarova, A. M. Rozhnov Chemical Department, Kuibyshev Polytechnioal Institute, Kuibyshev 443010, U.S.S.R. Significant deviation of the system from ideality can be seen in the mixturers of liquid organic substances, containing associated components, we investigated the equilibrium of the chemical transformations, going with the interaction of defines c4 " C6 of normal" ^ iso-structures with alcohols Cj - Cg and carboxylic acids /formic acid and acetic acid/ forming non-ideal mixtures. The investigation was conducted within the range of 343 to 403 К and the changes of the molar ratio of reagents from 6/1 to 1/6. Three groups of reactions go in those coditions: - interaction of olefine with alcohol or acid with the formation of corresponding ethers or esters; - migration of the position of alooxy- or alcoxycarbonyle group along hydrocarbon chain of the ether molecule; - migration of the position of a double bond in an olefine molecule. Practically the whole oomplex of reactions reaches equilibrium simultaneously. The equilibrium constants of the two latter groups of reacions do not depend on the composition of the reacting mixtures in the whole investigated range of concentrations and can be interpreted as a thermodynamic. The concentration equilibrium constants of the synthesis reaction of the ethers and esters К* - Xefcher/ )^lcohol- Wine ^ Kx " xester / xacid"xolefine ( x is a "°lar faction of a component) showed clear dependence from the composition of the reacting mixture. The unexpected fact was that the forms of those dependence have differed among themselves. In Kx - the ratio of reagents coordinates sharp lessening of K^ as well as the stabilization at the molar ratio alcohol / olefines 2/1 was seen. Analogous dependence was found in the system tertbutylbenzenes - tertbutylphenols wich was close to the above-mentioned one in terms of the degree of assotiation of components wich had been investigated by us earlier. The parabolic dependence was shown for KL in the same cooni nates. The minimal function lies in the area of equimolar ratio of reagents. The cause of such substantial difference might lie in the greately different association of alcohols, phenols and carboxylic acids. The introduction of the coefficients of activity in the calculation permitted to linearize the dependences found and to interpret the concentration equilibrium constants of the interaction of alcohols and acids with the olefines as a thermodynamic ones. The . coefficients of the activity of components were calculated by the UNIFAC method after critical evaluation and selection of dependable parameter of the intermolecular interactions. ISO V.V.Sofcolov Leningrad I technological institute for the Pulp and Paper Industry,USSR THERMODYNAMICS OF SOLUTIONS OF HYDROXYL CONTAINING COMPOUNDS Cellulose is the mast abundant renewable raw material in the world,the important camponent of cotton textiles and paper,and it has many other practical uses. The most common building unit in natural carbohydrate polymers is a -form of glucose known as glucopyranose.The carbohydrate po lymers which occur in nature are very varied in structure.They may contain between ten and a million sugar units in either a li near or branched arrangement,and the units may be all of the same type or of several types.Many different sugars occur as building units,but arly all,carbon atoms and only differ otherwise in one group. fit present there are many reports containing the physico- chemical and thermadynamical data for proteins,nucleic acids and electrolytes solutions. However,there are no systematical data of physico-chemical and thermodynamical properties for the sugars and polysaccharides < 1 - 5 ). Earlier,we have investigated the electron paramagnetic reso nance spectra of copper ions in mixtures containing polyhydroxyl compounds and ethylendiamine or ammonia.The comparison with cop per ion spectra in pure solvent (ethylendiamine or ammonia) in dicates distinct differences wich are caused by changes in the structure of the copper complex (6). The enthalpy of glucose solution in water,saccharose in water and 0,9 m solution of NH^CL in the Interval of 0,2-2,8 m were measured by means an isothermic calorimeter at 25* С . For the same hydroxyl containing compounds the heats of for mation with coppei—ammonium (cuam) and cadoxen solution (for methyl glucoside,glucose,xylose,cellobiose and cellulose per glucose cycle) was determined.The enthalpy of interaction to one group OH was calculated either for these compounds. From experimentals data the analogous calculs for methanol, ethanol,ethylenglycol,xylose,saccharose,cellobiose,starch and carboxymethyl cellulose in solutions of copper-ammonium ( С*и»=°,18Х, Co, =177. > were carried out. From results obtained the conclusion was made about the cha racter of hydroxyl compounds interaction with the complexes stu died. REFERENCES: 1! Biochemical Thermodynamics, Edited by M.N.Jones, N.Y. (1979),192; 2) L.B.Clapp,The Chemistry of the OH Group.,<1767); 3) D.A.Rees,The Shape» of Molecules.Carbohydrate polymers.,London,(1967): 4) B.L.Browning,Methods of Wood Chemistry.,V I-Il, N.Y.,(1967)5 5) V.V.Sokolav,V.G.Tsvetkov,A.V.Ivanov.,J. Appl. Chem., (USSR),3(1983),501; 6) V.V.Sokolov,Paperi ja Puu, N3, (1971),p.1. 151 1 t + + •THERMODYNAMIC PROPERTIES Oi IONS [CeH^PO^ and [Ce(!'2?C^1 Ш AQUEOUS SOLUTIONS l.A.Dibrov, D.E.Cbirkst Leningrad Mining Institute, Leningrad, 199026, USSR The thermodynamic properties of dibydrophoaphate cerium (III) ions were estimated from solubility data of solid CePO. in aqueous solutions containing 2.6 - 6.0 mol H,PO, per litre at313 - 365K, .lir;uid / solid ratio being 100 1/kg. JEquilibrium concentration of cerium in solutions was determined with spectrophotometrie analyse *itb' araenaso Hi. Previously it was shown that in these conditions She equlibrium solid phase is rabdochanite CePO••0.5H?0.Temperature dependence of solubility з / mo.l»l was approximated by equation: In s = -14.040 + 2657/T with CJ (96%) = 5»I0"5mol-1"1. The solubilities at 298K were confirmed quite good by the computer calculations of solubility with the minimization of tfibbs energies method. The Gibls energies of formation of the ions in question were estimated from [11» of other species in the solution - from usual reference books and databases. The hydrogen ion activities in these solutions were taken from [1], The activity coefficients of other ions '8-г* were suggested to be connected with <ГН+ by equation: 22 tfjit = tfH+ . The dissolution enthalpy of cerium phosphate was deteinined t>y derivating temperature dependence of (jibbs energy of this process. The entropy of this process calculated from the Uibbs 2+ [CeH2P04] -1815 -1957 51.4 + [Ce(H2P04)2] -2944 -3083 125.4 REFERENCES 1) I.A.Lebedev, Yu.M.Kulyako, Zhumal Heorganich. Khim. (J. of Inorganic Chem., Russ.,USSR), v.23,N.12,p.3215-3224,1978. 152. BORATE GLASSES (MELTS) AS ASSOCIATED LIQUIDS AND THEIR THER MODYNAMIC PROPERTIES. N.M.Vedishchevo, B.A.Shakhraatkin Institute of Silicate Chemistry, Academy of Sciences of the USSR, Leningrad 199155. USSR. Borates are'important components of many industrial Glasses, enamels, coatings. Information on their thermodynamic properties enables many technological and fundamental problems dealt with the nature of vitreous state to be solved. A calorimetric study of alkali borate glasses and crystals was carried out. Enthalpies of solution in 2 H nitric acid were measured for vitreous borates containing (mol %) 0^0 Li~0, 0-55 Na20, K20, RbgO, O-'0 CSgO and for crystals MgO-nBgO,, where M = Li, n = H3| M = K, Rb, n e 1 7 5 * . M = Na, n = 1 T H i И = Cs, n = 1 f 5, 9. Enthalpies of formation from oxides were calculated for all the borates studied using their enthalpies of solution. Lithium, sodium, potassium borate melts containing up to 4C% M 0 were investigated at 973-1475 К by the EMF technique and their integraa l and partial thermodynamic potentials (enthalpies, entro pies and free energies) were determined. The experimental data obtained by.both methods indicate that alkali 'borate glasses and melts can be considered as associated liquids. This enables their thermodynamic properties to be de scribed and calculated adequately on the basis of minimum of ex perimental data and assumptions. The model of the ideal associated solutions is used to calculate the relative content of different structural and chemical units (associates) in alkali borate glasses and melts depending on their compositions and temperature. The quantities of different associates define the structure of glasses (melts) and, hence, their properties. Prom the mole fractions of different associates (groupings) in borate glasses and melts • some of their properties which depend additively on the ratio of these groupings in glasses (melts) have been calculated. The results obtained are in satisfactory agreement with available experimental data. This cives evidence of the validity of the model chosen. 7.53 ENTHALPIES OF DILUTION OF AQUEOUS SOLUTIONS OF SMALL PEPTIDES AT 298 К O.V.Kulikov, V.G,Badelin Institute of lion-Aqueous Solution Chetniatry, USSR Academy of Sciences, Ivanovo, 153045 USSR. A.iiielenkiewicz,rf.Zielenkiewicz _ Institute of Physical Chemistry, Polish Academy of Faiences, Warsaw, 01-224 Poland, The present paper yields the results of measuring the enth alpies of dilution of the aqueous solutions of a series of di- •ind tripeptides onraicrocalorimeter LK B 10700-2 ab 298.15+0.01 K. The contributions from the side allcyl radicals (methylene group, alanine, valine and leucine radicals) into the value of the en- thalpic coefficient of pairwise interaction peptide-peptide, A2, are calculated on the Ьазе of the data obtained. Linear dependen ces between the contributions from the side radicals А.ЛН) and their Van der Waals volumes are obtained. The conclusion is made that the contributions from the hydrophobic interaction of the side alkyl radicals into, the value of the enthalpic coefficient of the pairwise interaction are determined by the size of these radicals, and the magnitude of the contribution from the hydro- philic interaction relates mainly to the molecular dipole mom ents. Linear correlation between the enthalpic coefficient of tri- pletic interaction Л, and the number of water molecules in the first solvation shell is discovered for the aqueous solutions of dipeptides. The analysis of the enthalpic coefficients of pepti de-peptide interaction is carried out on the base of three-stage model of peptide association of Gibson and S^heraga. The conclu sion is made that the enthalpic characteristics of peptide-pep tide interaction are determined by the number and nature of the functional groups that constitute these molecule», as well as by the structure of the asaociates formed. 154 HEAT CAPACITY CHARACTERISTICS OF ACETOMITRILE MIXTURES WITH AMIDES A. M. Kol ker . M. V. Kul i kov, Al. G. Krestov Institute of Non-Aqueous Solution Chemistry, USSR Academy of Sciences. Ivanovo 15304S USSR. Polar aprotic solvents, to which amides and nltriles as well as their mixtures refer, are of considerable interest for researchers and widely used in modern technologies. We have measured heat capacities of binary mixtures of acetonitrile with formamlde CFA3.N-methylformamide CMFA3. N,N-dimethylformamide CDMFA3 and hexamethylphophoric triamide CHMPTA3 over 283-338 К temperature interval. The measurements were carried out on the adiabatic-shell calorimeter of container type with O. OSS* precision. The following heat capacitiy characteristics of the mixtures studied have been calculated: excess CC *3, apparent СФс Э, partial molar CC Э heat capacities of the components. The standard partial molar heat capacities of amides in acetonitrile САЮ are close In their magnitudes to the values of molar heat capacities of pure amides and at 208 К С° equal Очпо1"*.К~'Э: 99.6 for FA, 135.9 for MFA, 134.9 for DMFA and 2BS.6 for HMPTA, respectively. A constant contribution into С value from CH -group has been noted; it equals. 27. Э ' Лчпо1~'.к"' at SOS K. The contributions into the change in heat capacity at solvation of amides in AN have been calculated within the frames of the Scaled Particle Theory. The main contribution into Д . C° •olv p magnitude for the systems studied is made by the effect of cavity formation in solvent. Opposite to the aqueous solutions of amides that were studied in our laboratory before, where the contribution into heat capacity of solvation from the Interaction is positive, it Is negative for the amide solutions in AN. Using the statistical theory of McMillan-Meyer,, the parameters of interparticle interactions in aqueous and acetonitrile solutions of amides have been determined, it is being shown that: a) in the aqueous solutions, the value of the pair interaction co efficient CA5 reflects the hydrophobic Chydrophillc) charact er of the interaction between amide and water; Ы for the solutions of amides in AN, the temperature and pressure derivatives of the coefficients of pair and three-fold interac tions have the signs that are opposite to the respective values in the aqueous systems. 155 PROBLEMS OP SOLVATION AMD MfiSOHOKPHISU Oi1 LlQUIIJ-HUS£ CtiLLULOSE- ETHiiRIC MATERIALS V.V.Myaaoyedova Institute of Non-Aqueous Solution Chemistry, U3oK Academy of Sciences, Ivanovo, USSR Problems of solvation and mesomorphism in non-aqueous solut ions of cellulose and its derivatives are urgent from the scien tific-technological viewpoint. The present work is aimed at establishing the regularities of the influence of solvent nature and composition, structural and chemical modifications of cellulose and its derivatives in non aqueous solutions on formation of lyomesophases in multicomponent cellulose-otheric systems, at revealing the"interrelation between rheologic properties and phase transitions, at elaboration of new cellulose-etheric multicomponent materials with predetermined properties for the development of the technological processes of cellulose treatment. The concept of prediction of the solvency of non-aqueous solvents for cellulose and its derivatives has been developed. Extended material on phase transition diagrams in the inter relation with the rheologic parameters of the solutions of cellu lose and its ethers, that has been obtained experimentally, is given. Given is the comparative analysis of theoretical and exper imental parameters of solvation and mer,omorphism of the cellulo se-etheric systems, that have been obtained from a complex in vestigation by the methods of polarization microscopy, rontgeno- structural analysis, differential scanning calorimetry and ther mochemistry, rheology. Identification of mesophases is carried out and polymorphism of the systems studied is proved. New multifunctional cellulose-etheric materials (densifying agents for printing dyes and pastes, glues, varnishes, membranes, etc) are developed and several technological processes are im proved on the base of fundamental researches. 156 INFLUENCE OP STRUCTURAL-CHEMICAL MODIFICATION OP CELLULOSE ON THER- MOCHEMICAL PROPERTIES OP MULTICOMPONENT SYSTEMS ON THE BASE OP NON AQUEOUS SOLUTIONS OP THE CELLULOSE ETHERS AND ESTERS I.K.Yuryev, N.A.Zavyalov, V.V.Myasoyedcva, G.A.Krestov Institute of Non-Aqueous Solution Chemistry, USSR Academy of Sciences, Ivanovo, USSR The studies on the intermoleoular Interactions in system "po lymer 1 - polymer 2 - solvent" is of interest relative to the im provement of the cellulose-etheric membranes* The-present work is aimed at establishing the basic regulari ties of the influence of the cellulose derivative concentration in solution, of solvent nature, of hydroxyl group substitution degree on the thermoohemical characteristics of solution and transfer of polyethylene glycol (PEG) in the solutions of hydroxypropylcellul- ose (HOPC), cellulose acetates (CA) and other derivatives. The objects used in the present work are: HOPC of "E" type of "Klucel" (USA) orlgine with molecular mass 60000 and degree of moli substitution 3,0; CA with the average polymerization degree of 250 •» 300 and subatitution degrees 0.63, 0.96, 1.55, 2.43, 2.90 that were synthesized in the scientific-production unit "Polimer- sintes" {Vladimir, USSR); PEG from "Merck" (Germany) with molecular mass 400 t 20. н Solution enthalpies Аьо1п were measured on hermetic isoperi- bolic miorocalorimeter. The concentration interval of the oellulose ethers in solution 'was О ч 4 mass%. The calculation of the standard solution enthalpies A. ,H° referring to infinite di lution was carried out by the method of linear extrapolation of unitary heat effects. The measurement relative error did not exoeed 1 56. Experimental results are discussed from the positions of the influenoe of the processes of solvation and association of the cel lulose derivatives on the energetio parameters of PEG — cellulose ether interaction. The data on A. Ha for the solutions of CA with SD<0.63 allow to oonclude that H-bonds PEG-CA are not realized due to solv ation of CA by solvents and intra- and intermolecular interactions due to the presence of OH-groups in low-substituted acetates of cellulose. Mathematical model ia elaborated and a good agreement, between experimental and theoretical values of the thermodynamic parameters of polymer component interaction and physico-chemical properties (dielectric constant and electron-donor numbers) of solvents» 157 THERMODYNAMICS OF COMPLEXAITION OP SILVER(I) WITH AMINES IN ACETONE AQUEOUS SOLUTIONS V.H.Markov, V.A.Sharnin, V.A.Shormanov, G.A.Kreotiv Institute of Chemistry and Technology, Ivanovo, USr.'I? Theoretical investigation of amine complexation reactions of silver (I) in aqueous solutions of acetone is of particular inte- x-est due to peculiarity of reagent solvation in these media. It is demonstrated experimentally that during the solution of . aliphatic amines (methylaffline,ethylaMiine,ethylenediamine) in aqueous acetone solvents there take place the processes which go beyond the зсоре of the definition "solvation".That is why when studying reactions taking place under such conditions it becomes necessary to consider the solvent both as a chemical reagent and as a medium for the reaction to proceed. Stability constants of silver (I) complexes with methylaraine,ethylaraine,ethylenediamine, pyridine and 2,2-dipyridil in aqueous -acetone media as well as heat effects of their formation are determined by potentiometric and thermocheinical methods. Complete thermodynamic analysis of complexation reaction in terms f reagent solvation changes is made. It is found that amine participation in chemical interac tion with acetone results in anomalous changes of thermodynamic characteristics of the processes studied with solvent composi tion (changes of complex stability,enthalpy and entropy of the reaction,increase of ligand solvation exothermicity and so on). Equations which make it possible to take into account the con tribution of chemical interactions into AG0 of the reactions are derived. With specific interactions taken into account it is Siiown that not only do absolute values of complex stability constants change, but also the character of their changes de pending on the solvent composition, which is of principal sig nificance for establishing regularities of solvent churacter effect on chemical equilibrium shift in solutions. 156 THERMODYNAMIC AMD TRANSPORT PROPERTIES OF I-I ELECTROLYTES IN ACETONITRILE AT LOW TEMPERATURES. L. P. Safonova,A. N. Kinchin.B. K. Pasasia, A. N. Zabyvaev Institute of Non-Aqueous Solution Chemistry. USSR Academy of Sciences, Ivanovo 153045, USSR In our laboratory performs sistematic investigations on the influence of low temperatures on the thermodynamic properties on nonaqueous solutions of electrolytes. The present paper carries the results of the thermodynamic and conductometric investigation on 1-1 electrolytes in acetoni tr i 1 e. We have determined the dissolution enthalpies of Nal. NaBr. NaBPh . Ph^PBr, Pr4NBr, Et^NX Cwhere X=C1 .Br .13. and conductivity of R4NI С where R=Me, Et, Pr. ВиЭ , Ш Cwhere M=Na, K.Rb.Cs3, Pi^NBr, Bu NBPh , Ph PBr at 2ЭЭ to 31SK in acetoni trlle. The conductometrlc data have been anal 1 zed on the base of Lee and Weaton equation. Limiting conductance of Individual ions was determined on the basis of literature data on transfer numbers. The conductometrlc Investigation has shown low ionic association at all temperatures. Standard enthalpies of solutions of electrolytes were defined with extrapolation method based on Debye-Huckel theory and nonconsi der 1 d ionic association. The thermodynamic values of Individual ions С Л ,Н?Э we obtained. using reference salt Ph PBPh . Analysis of the influence of temperature on the state of ions in solution was been performed using model : Л•e l,Y 1? = A«1 ,Y1f + Aea vY 1? + Aai rY 1? + Ain. tY 1? where A ,Y? is contribution from the electrostatic Interaction on the ion with solvent; A Y? is contribution from the cavity formation of cav i ' appropriate size within the solwent; A. Y? is contributions from other interactions of the ion ml 1 with the solvent; A Y? is contribution from structural changes of solvent. To discuss Influence of temperature and variety of ions on the process of sol vat at ion and state ions in solution. 159 MIXED SOLVENT EFFECT OH THERKOD'JTHAJHCS OP HICKKL(II) COMPLE3CATION REACTIONS WITH А11ЮТ V.A.Shonaanov Institute of Chemistry and Technology,Ivanovo, USSR Influence of the solvent on the cumplextition reactions is stu died in terma of changes of reagent solvation thermodynamic cha racteristics. On this basis regularities of aqueous-organic solvent effect on thermodynamic characteristics of nickel(II) reaction with amine are established. It is found that Gibbs energy change limits of complexation reactions with change of aqueous-organic solvent composition and in the absence of specific interactions do not exceed those of amine, and dependitig on amine and solvent character vary from О to Gibbs energy transfer of amine taken with the opposite sign. Depending on aqueous-organic solvent composition the salt ef fect may result in increase or decrease of amine nickel(II) comp lex stability.Interconnection of this phenomenon with the change of salt effect sign and its influence on amine stabilisation'with solvent non-aqueous component concentration growth is demonstrated. Influence of the solvent on complexation reactions heat effect change is investigated. It.is shown that there exist a regularity of heat effect changes with those of aqueous-organic solvent com position. Changes of reaction heat effects depending on solvent and amino character vary from 0 to amine transfer enthalpies taken with the opposite sign. This is due to the fact that depen ding on amine and solvent character transfer enthalpies of comp lex ions may vary from those observed fcr sol vat ел. up lex to the sum of transfer enthalpies of nickel (II) and offline.Regularities found for nickel (II) complexes are also observed for mixed sol vent effect on ccuiplexation of cadmium (II),silver (I) iousi with amine. This demonstrates the general character ;f regularities found for changes of thermodynamic characteristics'! of mixed sol vent в. 160 THERMODYNAMICS OK PROTOLYTIC EQUILIBRIA IN THE SOLUTIONS OF AMINES, AMINO ACIDS AND COMPLEXONES L.A.Kochergina, V.P.Vasilyev Institute of Chemistry and Technology, Ivanovo, USSR A.B.Kochergln Institute of Non-Aqueous Solutions Chemistry, Ivanovo, USSR Numerous questions of the thermodynamics of protolytic equi libria, In particular, a large number of the reactions of acidic- basic interaction with participation of chemical compounds of dif ferent nature-amines, amino acids, complexonee, inorganic acids - have been considered only generally hitherto; this does not cor respond to great practical and scientific significance of these compounds. The present paper carries out determination of the enthalpies of the acidic-basic interaction in the solutions of ammonia, imid azole, benzimidazole, histamine, L-hletidine, a- and /^-alanine, L- asparagine, L-aspartlc acid; step equilibria in the solutions of complexones - iminodiacetic acid, nitrllotrlacetic acid, ethylene- diaminetetracetic acid and their phoephorylated analogues - have been investigated over 283-328 К temperature interval against the backgroung of several electrolytes. The measurements have been performed on the isothermic-shell calorimeter with automatic tem perature recording. Modern approaches require the application of computers to calculate complex acidic-basic equilibria in the cases when 5-7 reactions can proceed in the system considered. Concrete conditi ons of the thermochemical experiment have been optimized with a special RRSU program on EC-1050 computer. The thermodynamic cha racteristics of dissociation of a series of compounds have been found by Joint usage of the results of thermochemical and poten- tiometric measurements. Gurny's concepts were used to analize the thermodynamic cha racteristics of the reactions; that allowed to consider heteroge neous chemical processes from united positions. Four types of pro ton transfer have been marked out and the criteria allowing to ma ke such a gradation of the reactions of acidic-baeic interaction in the solution have been proposed. The comparison between tempe rature-dependent and -independent costltuente of Gibbs energy and dissociation enthalpies has allowed to predict the magnitude of temperature & at which the thermal effect of reaction becomes zero. 161 THE PECULIARITIES OF SOLVATION THERMODYNAMICS OF PORPHYRINS AND THEIR COMPLEXES IN NON-AQUEOUS MIXTURES Trofimenko G.M., Berezjn M.fl. Institute cf Non-Aqueous Solution Chemistry of the USSR - Ac.Sci., Ivanovo, USSR The study on porphyrin solvation in binary and multi- component mixtures is of great interest because it allows to obtain important information on porphyrin-solvent inter actions, on the properties of porphyrin solvation shells ind their influence on the behaviour of porphyrin molecules in solution. In addition, such studies allows a better com prehension of the behaviour of natural porphyrins in biolo gical systems. The present work is a themodynamic investigation on so lution of blood porphyrins-deuteroporphyrin (H2DP) and me- •aoporphyrin (H2MP) and their Zn-complexes in carbon tetra chloride, ethylacetate and their mixtures. The studies were carried out by solubility method under isothermal satura tion condition. The temperature range investigated was 293- 318 K. Analysis of the data shows that universal solvation of porphyrin molecules in carbon tetrachloride is 2,5 time lower than in ehtylacetate.The peculiarities of porphyrin resolvation, manifested step-wise decrease in H2DP solubi lity wiht increasing ethylacetate concentration, are found. Together with porphyrin molecule periphery resolvation,spe cific solvation plays an important role for Zn-complex so lutions with increasing ethylacetate concentration. It ma nifests аз extracoordination of ethylacetat.e molecules on the central Zn atom and approaches its maximum at 5:3 - 1:1 solvent ratio.Dependences of ZnDP and ZnMP solubilities on solvent composition over this range reflect the total ef fect of the two factors, viz. resolvation of the porphyrin molecule perifery and monotonously increasing extracoordi nation on the central metal atom. The process of blood porphyrin solution is endothermio in all the solvents investigated. The values of the stan dard solution enthalpies are considerably dependent on the nature of porphyrins and their complexes. Thra standard free solution energies are positive and show minima (e>:ept K2DP) at 5:3 - 1:1 solution compositions. PHASE TRANSITIONS IN LIVER MICROSOMES IN THE PRESENCE OF Mg+2 IONS M. A. Kisel, A. Ja. Lunevich, P. A. Kiselev Institute of Bioorganic Chemistry, Minsk, USSR Studies on the temperature dependence of different functional parameters of microsomal enzymes, e.g. cytochrome Рт450, revealed breaks or discontinuties in the Arrhenius plot at 24-32°C which have been attributed to a phase transition of phospholipids. Calorimetric studies of the lipid phase transition in microsomes, however, d?.d not reveal any temperature dependent changes above 5°C. In this report the detection of the phase transitions in the presence of Mg+2 ions is demonstrated. After incubation of microsomes in a buffer containing lOmM MgClg, a thermogram showed 3 low-energy transitions, with maxima at 18,27 and 32°C and transition enthalpy being about 0,1 kcal/mol each in terms of total content of phos pholipids. When investigating liposomes from isolated microsomal lipids, the addition of Mg+2 gives the only peak at 18°C. In microsomes this peak is likely to display a phase transition of phospholipids not participating in the interaction with proteins. It is known that Mg+2 and Ca+2 increase essentially a phase transition temperature of negatively charged phospholipids, e.g. phosphatidylserine. This fact and the thermogram of repeated scanning of microsomes allow the conclusion that the peaks at 27 and 32°C are due to the interaction 'jf Mg42 with negatively charged microsomal phospholipids surrounding proteins. A possible mechanism of the catalytic activity regulation of membrane-bound enzymes by endogenous divalent cations is discussed. T63 THERMODYNAMIC FUNCTIONS OF MIXING AND SOLVATION IN BINARY SYSTEMS SOLVENTS - HYDROCARBONS A.E.Shcherbina, L.M.Kaporovsky, E.I.Shcherbina Byelorussian Institute of Technology, Sverdlav St. 1Э-А, Minsk, 220630, USSR By method of calorimetry and vapoui—liquid equilibrium are determined thermodynamic parameters of alcans and aromatic hydro carbons mixes with the series of high-efficient polar hudrocarbqn extractors: N-Methylcaprolactam CN-MCL).Tetramethylensulfon fTMS), Glycols Altcylethers, Tetrahydrofurfuryl alcohol (TGFA), as well as with binary solvents based on TMS. Has been obtained mixing enthalpy experimental dnta array for concentrated solutions as .«ell as for areas of limit dilution. Concentration dependences are approximated by in terpolation equa tions. On the base of analytical dependences of integral thermo dynamic functions were calculated partial molar functions of solu tion components, as well as their limit values. The experimental data correlation of vapour-liquid equili brium and mixing enthalpy was made by means of UNIFAC-model para meters, the latter were used for new interaction parameters calcu lation correctly describing base systems. Baaing on found parame ters equilibrium characteristics and mixing enthalpies in binary systems were jointly described. Prediction errors were the follo wing fori vapour composition - not more tham 1%, boiling tempera tures - 0.S К, components activity factors - 2X, mixing enthal pies - up to 10'/.. Is made the estimation of enthalpio and entropic component contribution of free mixing excess energy. In the system contai ning binary solvents CTMS - N-MCL, TMS - TGFA) is realized the "compensation effect" having sufficiently high free term valu.2, what shows the raising importance of enthalpic factor by solva tion . On the base of mixing enthalpy experimental data'as well as of vapour-liquid characteristics were calculated thermodynamic salvation parameters (Двду <&HgV • AJSsv '" Solvation functions calculation is made for the component transfer from complete ga seous state into infinitely dilute solution. The «solvation enthal py and entropy characters depending on each system compii»ition are discussed. Solvation enthalpy values Separating into components «allowed to estimate enthalpy values of space formation as well as relative interaction enthalpies which present the measure o.f dnnor-ncceptnr interaction betwwen ST-electronic aromatic ring and solvents'' eie- ctrofilic centers. ej~ The estimating of specific interaction energy < A H ) in studied systems by means of two independent methods С calariinetry dnd chromatography) showed that the greater is specific interac tion contribution in simmarized salvation enthalpies values the more effective is aromatic-alcanes hydrocarbon mixing selective separation by means of selective solvents. 164 PHYSICO-CHEMICAL PROPERTIES OP .^-COMPLEXES OP METAL ANALOGUES OP TETRAPHISBYLPORPHIN WITH AROMATIC MOLECULES A.I.Vyugin, E.V.Antina, G.A.Krestov Institute of Non-Aqueous Solution Chemistry, USSR Academy of Sciences, Ivanovo 153045 USSR The phenomena of transport, accumulation and specific inter action of medicines with toxicants in living organisms are often conneotc-d with cpecific Jt-JT-interactions of the aromatic • fragm ents, of organic molec.'lOB with porphyrin-containlng biological structures. The aim of. the present 'work is to study the influen ce of the electronic ."structure of central metc.l atom in porphyr in complexes and of the nature of solvent aromatic molecules on physico-chemical properties of metal porphyrin-solrent molecular ^-complexes. Л new approach using thermogravimetric and calori- metric methods.have been applied for this purpose. Peculiarities of solvation of tetraphenylporphin complexes with Zn(II), Mn(II), Cu(TI) have been studied in benzene, tolue ne and para-xylene. Solution and transfer enthalpies of comple xes in the solvents studied have been defined calorimetrioally. Temperature intervals of setbility and compositions of the spe cific «-complexes (ZnTPP»2C6Hg, ZnTPP.ZCgHjCHj, (Ao)MnTPP.2CgH6f 2 ZnTPP«CgH.(CH3)2) have been determined and energetic charact eristics of intermolecular metal porphyrin-solvent interactions calculated.from the results of the thermosravimetric investigat ion on corresponding crystal solvates of metal porphyrins with solvent molecules» The reactivity of complex with respect to aromatic compo unds has been shown to depend considerably on the nature of met- al-porphyrin coordination bond and on the presence of axial li- gands on the central atom of cornplex-formator. Thus, opposite to ZnTPP«CgHg complex, in (Ac)MnTPP«2CgHg #-complex benzene molec ules are characterized by different energy of interaction with metal porphyrin and withdrawn from the solvate at different•tem peratures. It has been shown that tho specific яг-Ж-interaction with beiiiione uoleculen is not characteristic of CuTPP. It has been eotcbliahed that a consecutive introduction of two CHv- groupu into beiaene molecule lowers the energy of the intermol ecular interaction of ZnTPP with the aror.ia.tic molecules of to luene and para-xylene and causes a substantial change Jn the thermal stability of the corresponding ^-complexes. It has been concluded that in the process of the formation of X-complexes with aromatic molecules, Я*-system of the mac ro-cycle of the metal analogues of tetraphenylporphin acts as acceptor, and the benzene ring of the solvent molecule - as do nor of X-electrons. 165 SORPTION THERMODYNAMICS FROM MULT ICOMPONENT ELECTROLYTE SOLUTIONS H. N. Altshuler Institute of Carbonic Material Chemistry, Liberia'; Branch of the Academy of Sciences of the USSR, Kemerovo, USSR. The phase composition have been determined and the differential heats of ion exchange and adsorption from binary electrolyte solutions have been measured. Zeolite X, natural heulandite, ionexonangers containing functional carboxyl, phospi-oroacidic, sulfogroups arid crown ethers nave been studied as sorbents. Separation factors of cation mixtures of I, II, Ilia element groups, NHj ,. Pb and matricies of thermodynamic functions of sorp tion complicated by a complexation in the ionexchanger and solution phase have been calculated. Sorption partial heats in the binary systems are shown to depend linearly on the sorbat content in a solid phase. In this connection, the Gibbs energy changes during adsorption and ion exchange from multicomponent solutions are summed up including the additive contributions of partial values in the composition range investigated. As a result, the equilibria of ion exchange and elec trolyte adsorption in mult.i component systems can be discribed by the linear combination of equilibria in the binary systems. Both the calculated nomographs of NHJ , Pb2*content in natural heulandite which is in equilibrium with the multicomponent solution and the experimental data are given in the figure as an example. The values estimated coincide with the data of direct measurements, with an error taking into account. Fig. The calculated dependences or N'Ht (a) and Pb (b,c) content (mol fraction)in zeolite on equilibrium solution composition. a«« «= «Itaer a«t • ""I/dm3 : 1 - 0.002; 2 - 0.0033; 3 - 0.005; 4 - 0.0067; 5-0.01; 6 - 0.013. Dotted - experiment at Cuc#= CNa«= Сцое = 0-0067 3 3 mol/dm " - —и-._я . r. л ««т. „ * ™. „ „ „„т. ,„ aCta. mol/dm ; 7 - 0.005; 8 ""0.01; 9,- 0.015; 10 Лки c 3 0.025. Dotted - experiment at CKtt" Cs«- 0.01 rrol/dm ; анакг CLKC,- ae*a, mol/dm3; 11 - 0.0033; 12 - 0.0067; 13 - 0.01; 14- 0.013. Dotted - experintent at Сцде» Ска = Ccsct= n- 0067* mol/dm5. Кб THERMODYNAMICS OF MICROSCOPIC LIQUID FILMS V.G.Babak Chair of Physical and Colloid Chemistry, A*U,C.Institute of Food Industry, 109803 Moscow, U.S.S.R. The thermodynamics of microscopic liquid films based on the . two dividing surfaces convention in the Gibbs' excess method has been elaborated /1/, This thermodynamics is the extension of the thermodynamics of plane-parallel liquid films (elaborated for the first time by Rus- sanov /2,3/) on the so-called transition region of the liquid film (situated on the boundary between the plane-parallel region of the film and the adjacent meniscus of the bulk phase) where the disjo ining pressure (characterizing the interaction surface forces) va ries sharply (see Fig.). (a) „ (b) (c) Bulk dispersion medium (phaseoi) Fig, (a) The microscopic thin liquid film appears in the region of contact between two fluid particles (phases/J) in the li quid dispersion medium (phaseoi), (b) The transition region of the film is situated between the plane-parallel region of the film and the bulk dispersion medium, (c) The disjoining pressure П in the transition region of the film undergoes the sharp variation in Its amplitude and sign. One starts from the fundamental equation of the open subsys tem which Includes the film of area A : dSJ - - S.dT - P.dVf -r?(H).A.dII + 2 C(H).dA -S^.dyvfi (D where Q is the great thermodynamic potential ; S, N. and M, are entropy, number of molecules and chemical potential of i-th com ponent of the subsystem, respectively ; T is the temperature j V- Is the volume of the film ; H is the local film thickness ; G"(H7 Is the local lnterfaclal tension of the film ; Л(Н) is the dis joining pressure ; P - Рл - Pfl , Prf and P^ are hydrostatic pressu res in the phases Ы. and jb , respectively. Usingthe variatlonnel procedure one obtains from Eq.(l) the fundamental equation of equilibrium of the film In the transition region ^j Gf(H).k(U) • ЛОО.сов f(H) + P - 0 (2) where k(H) Is the mean local curvature of the film surface t *tf(H) la the local slope angle of the film profile ; and the Glbbs-Duhem In equation nun - -2.ъс?т/ъв\ о) On the base of the elaborated thermodynamics of microscopic thin liquid films the generalized line tension theory has been su ggested which generalizes and conciliates different approaches to the definition of the line tension term given by different authors. The effect of the physico-chemical factors (lnterfacial tension, capillary pressure, radius of the film, parameters characterizing the form of the f? (H)-leathern, etc.) on the line tension has been Investigated by the numerical modelling method. Particularly, the difference between the line tension according to Gibbs (our nota tion)) ZG given by the expression P V U 2 ld & " "JJ ' P " Ъ'Х*" * Jc№)»dA • 2yrrf. rG (4) id ' A.Q(Hf) + tV4/rt • 2.C?0. A#(nf) -J ПШ.аН ; (6) Hf Gg is the lnterfacial tension on the boundary between two bulk phases) Is elucidated and demonstrated by numerous computation ex amples. The theory of adhesion of fluid particles has been elaborated which relates the adhesion force f* to their radius II and the spe cific interaction free energy (the specific energy of adhesion) f a -Va'7r.*-*M(Ht) (7) where Va is a function of «.be perarae ters (Qtt , В, Л, etc.) varying in the range of 0,5 • 1,0. It has been demonstrated that the work of the pull-off force f ' is equal to _ W a ' J *.<•>•«"* Уа.7Г.Н.^Н-.<1 • Д-) (8) rj* ° " О (where /7 is the depth of the coagulation minimum (see Pig.), P is the capillary pressure) and may overpass 1000 times and more the corresponding work of separation of two nondeformable partic les. This finding has been put in the background of the elaborated criterion of the aggregative stability of emulsions which accounts for the effect of the deformablllty of particles on W . REFERENCES 1) V.G.Babak, Colloids Surf.,25 (1987) 1; 25; 28 (1987) 123: 30 (1988) 307, 2) A.I.Ruesanov, J. Colloid Interface Sci. 53 (1975) 20. 3) A.I.Ruesanov, Phasengleichgewlchte und Grenz riochenerscheitiun- gen, Academle Verlag, Berlin, 1976. 4) J.A. de f'eljter, A.Vrlj, J.Electroanal. Chem. 37 (1972) 9. ire THE ELECTltOUIC GHARGJS AKD THE POTENTIAL DISTUIBUTIOiiS IK SURFACE I REGION OF OXIDES biODIiiTED BY IMPURITIES. G.S.Bo]cun,li.V.Bot;omaa'jva,u.A.Slessarcnl:o,aiid I.M.Zharsky Electrochemical Dept.,Byelorussian Institute of Technology,' Sverdlov Str.,13,i.iin3k 220630,USSK. For description of potential distribution in surface region of oxide the method of local thermodynamic equilibrium is used* The semiconductor case of the oxide is considered* Electrochemi cal potentials of electrones and holes are expressed in terms of single electron b'ermi-Direc distribution function. Both the dis tribution of the electronic density and the potential distribu tion are determined by condition of the electrochemical potential over the volume of system constancy* Different cases of the impu rity centres distribution are studied in accordance with condi tions making of the film. The correlation effects of impurities interaction with each other and those nith basic material atoms are simulated by smearing of energetic levels in the gyp between the top of valence and conduction bands. The system of thermody namic equations is completed by differential analogue of the Fouasson equation. The spatial electric charge distribution in dependence with the potential, the defect distribution, and the film thick ness is calculated by numerical solution of closed equations. Detailed consideration is done to investigate an integral oxide characteristic namely its surface region capacity in dependence with the surface potential. A spetial attention was given to the simulation of passivoting oxide film on the metal surface. Deep and shallow donor levels are.considered with varions lows of their distributions inside the aai.iple. Impurity center field ionization effect on Volt-Parade characteristics of the simulated system is investigated in the near surface region at high electric field values. Obtained theoretical dependence of inveree electric capa city square as a function of external potential is in good quali tative and quantitative asrieiacnt with experimental data. 169 ' IIIVbSTIGATION OF THE SURFACTANTS' ADSORHLIOH Oi) THE HiTHOPHILIC SURFACE S.A.Savintseva, I.U.Sekisova Institute of Inorganic Chemistryt Siberian Branch of the US3H Academy of Sciences . The character of adsorption three classes of surfactants- en the hydrophilic surface have been compared under equal conditions. Physical adsorption of sodium dodecylsulfate on the aerosil-200 (anionie active surfactant) has been observed independently of the medium, due to dispersion interaction. It is shown that the adsorption of eetyltrimethylaiimoniura bromide on hydrophilic surfaoe Is of a complex nature. First there occurs an irreversible chemical adsorption of surfactant cation to form an insoluble product, which is followed by a reversible phy sical adsorption. On the base of the IR-spectroscopy and chemical studies a mechanism of adsorption of oxyethylated products (non-ionogenic surfactants) has been studied on the aerosil-200, Calcium Carbonate, silica sand and grlnted glass. • It was observed the relationship of the values of contact an gles and of the value of the adsorption of investigated surfactants at the different concentrations and temperatures. At the same equi librium concentrations of the surfactants the adsorption values for investigated adsorbents have been of the same order. One-has revea led the influence of the additions of the dlx'ferent electolytes on the character of the adsorption of non-ionogen surfactants. The heat of the adsorption of oxyethylated product has been studied. Calorimetry method was applied. The value of the heat of the adsorption of oxyethylated products on aerosil-200 is 60-65 kj/uiol. Taking Into account the experimental results is was supposed that the nature of the adsorption was complex one. Chemosorption is caused by the interaction of the hydroxy1 of the aerosil silanol group.with the oxyethylated product hydroxylic group. This conclusion resulted from the study of adsorption at different pH at 20,50 and 70eC. 170 SURFACE PROPERTIES OF SOLUTIONS OF LIQUIFIED GASES. I.J. Sulla, V.G.Baidakov, V.P.Skripov Institute of Thermal Fhysics, Urals Division of USSR Academy of Sciences, Sverdlovsk. USSR The Sugden parameter Q and the surface tension 0" of Ar - Kr mixtures and the gas - liquid systems He-0t and He-C2He have been determined from the boiling point to the temperatures close to the critical temperatures and the pressures from 0.1 to 6 MPa by the differential capillary method. For every mixture two or three series of measurements were made on the assemblies of glass capillaries of different radii (from 0.09 to 0.64mm). The total relative error of determination of the Sugden parameter is 0.5 per cent at the boiling point temperatures and 1.5-2 per cent near the critical point. A qualitatively different type of pressure and composition dependence has been obtained for the systems Не-0г and He-C2 He : 2 the decrease of O in the system Не-0г and the increase of a* in the system He-C2H6 with increasing of pressure. The derivative (dG /dp )T decreases as the temperature increases for both solutions, and becomes negative for the system He-C2He at T=0.9Tc. The surface tension of thie mixture does not depend on the pressure and composition of the soluted gas within the experimental error and hence the excess concentration of helium in the surface layer is practically equal to zero. Helium is the surfactant for the helium - oxygen system. The adsorption Г||г = - (Ъ THERMODYNAMICS OF NON-EQUILIBRIUM SURFACE PHENOMENA N.N.Kochurova Chemistry Faculty, Leningrad State University, Leningrad 199034, USSR The results of experimental and theoretical investigation of non-equilibrium processes on fresh surface are presented. With using methods of Irreversible thermodynnamics the adsorb- tion equation for a non-equlllbrlum process of adsorption, orienta tion and the ionic double layer formation Is derived. It is shown that the correlation between the changes of dynamic surface tension V and the electric surface potential % exists. If t Is the age of surface, the following conclusions are obtained for various particu lar cases: (a) dy/cft -*• 0 as t -+ m and there is no linear term "?ith respect to A% = X ~u» ^ tne dependence of Д7 = 7 -7 on A% If orientatin of dipoles tis slot: and diffusion equilibriutm exists00 ; (b) civ/dx -»• const as t -»• «0 an* there Is no linear term with respect to Д% In the dependence of Д7 on b.% if orientation Is rapid and jhere is no diffusion equilllbrlum for dipoles; (c) dj/dx, -*• const as t -*• <» and there Is no linear term with respect to AY in the dependence of A7 on A% If surface potential is caused by the ionic double layer formation. This result is of practical Importance since it can help in finding the nnature of surface potential. Interrelation between bulk entropy sr and surface entropy Ss in non-equillbrlum conditions is determinated not only by dependence of surface tension on temperature, but also by the terms relating to diffusion and polarization. Connection of mechanical 7 and thermodynamic о surface tension under non-equlllbrlum conditions follows from equation о - ТГ+Еф - V% )Bl where u.± the electric chemical potential, N the number of particles (molecules or ions), Indices a, a, i refer to the whole surface layer, to the bulk liquid phase, to the kind of particles. There are the connection between the dynamic surface properties and the evaporation-condensation rate. REFERENCES 1. N.N.Kochurova. The problems of thermodynamics of heterogeneous systems and theory of surface phenomena. Leningrad, LGU, J» 8 (1988) 172 A NEW APPROACH TO DETERMINING THE VOLUME OF ADSORBED PHASE DEPENDING ON BULK CONCENTRATION D.V.Marlnln. A.P.Golikov, A.V.Voit, A.V.Avramenko, V.Yu. Gluehohenko Institute of Chemistry, Far East Division, Aoademy of Soienoes of • the USSR, Vladivostok 22, USSR. A new thermodynamic approach has been worked out to determine the volume of the Interfaolal area between solid and binary solution of non-electrolytes considered as a uniform phase ('adsorbed phase'). Since the adsorbed phase volume 7 Is calculated here as a funotlon of the equilibrium bulk concentration, the approach Is rather usefi-1 In the thermodynamic study of systems adsorbent - non-Ideal two-component solution. The thermodynamic analysis of the systems described above is based on the following experimentally measured thermodynamic values: (a) surfaoe excess of adsorbat - the generally used oharaoterietio of heterogeneous system; (b) excess volume of heterogeneous system. Using the latter value allows to eliminate all arbitrary assumptions concerning the parameters of adsorbed phase including the conventional approximation of so-called 'rigid' adsorbed phase that states that either Vе or V? (partial molar volumes of components in the adsorbed phase) do not depend on the equilibrium liquid phase oomposition. The main idea of the approaoh can be formulated as follows: the volume of adsorbed опаве 7 and, therefore, its other parameters - composition xj, moles number n , components' partial molar volumes 7" and activity coefficients 7? - are calculated relatively to an ideal (referenoe) .system containing ideal (reference) surfaoe phase and ideal (reference) bulk solution. All thermodynamic parameters of both ideal and real adsorptional systems are unambigiously related to each other with a number of all possible independent thermodynamic equations and three assumptions concerning only the ideal system. The approaoh has been applied to the thermodynamic analysis of some experimentally studied and simulated systems adsorbent -binary solution. The results obtained here are In good correlation with ones obtained independently. A THJSRMODHJAMICAIi STUDY OF COMPLEX FORMATIOH IH CIIKLATING ION-EXCHANGE RESINS. S.\r.Kertman,8.N.Hajiev,G.M.Kertman Dept. of Chemistry,State Tyumen University,Tyumen,U.S.S.R. J.Reedijk Dept. of Chemistry,State Leiden University,Leiden, The Nitherlands. .Sorption of transition-metal ions by complex-forming re-* sins' results from the formation of coordinating bonds between the sorbed metal ions and ligand groups of the resin. The chela ting ion-exchange resins are used as selective sorbents, and the metal complexes with the functional groups of the chelating ion- exchange resins are used as catalyzers. The.mechanics of metal ions and chelating ion-exchange resins interaction has not been sufficiently studied. This lack of research work on the physico- chemical, especially thermodynamic, propertus restrains a wider use of resins. Sorption of transition-metal ions in resins AS (copolymer of styrene and divinilbenzine containing primary aminogroupn -NH2) occurs through the formation of the coordination bond only. The coordination number of metal ions is realized most fully at low loads of_resins (X). It causes a sharp rise in enthalpy of sorp tion at X+0 (Fig.1). Fig.1. Dependence of 4H° sorption of the ions: 1 - Cu2+ [1] , 2 - Ni2+, 3 - Co2+, Zn2 + Mn2+ on the load of the resin AS. An unusual dependence of the enthalpy of sorption on the resin load has been observed in studying the sorption of copper ions. Usually, with the loads being low, the energy discharge is the biggest, whereas sorption of copper ions in AS resin has shown a decrease in energy discharge at X •• 0. A decrease in energy discharge, with the number of coordination bonds between copper ions and aminogroups increasing, has been registered in measu ring the enthalpy of copper ions and polyamine complex formation. At the start of sorption copper ions in the AS resin, an endo- effect has been obsewed. This is probably connected with a big expenditure of energy on the dehydration of the aquocopper comp lex. The Irving-Williams rule reflects the changes in the stabi lity constants and in the enthalpies of formation transition-me tal complex, which follow the order: Mn2+ < Co2* < Ni2+ < Cu2+ > Zn2+ As is shown in Fig.1.,the Irving-Williams rule holds Rood for three-dimensional polylygands, as well. 174 -АН'ку-тое'* -АН" к J-mot' ,-4°* *~^&rbx Fig.2. ADF Fig.5. ES 467 Dependences of ДН sorption on the load of the resins. The polyampholytes ADF and ES 467 belong to the class of aminophosphonic acids. The functional groups ADF and ES 467 are the following: -NH-0H2-P03H2 and -CH2-NH-CH2-F0,H2 The only difference between these two lies in the presence, in the resin ES 467, of a methylene group between the styrenedivi- nilbenzine matrix and the functional group. Hence, the sameness of the dependences given in Fig.2 and Fig.3 • It's only in the sorption of copper ions,with the high loaded resin EB 467, that an endoeffect is obsewed. This is explained by the nitrogen atom's density of electrons being higher, which intensifies the nitrogen atom's protonization (formation of a zwitterion struc ture)' and simultaneously brings down its coordination capabili ty. Whereas, the copper ions and phoaphonic acid groups inter action, as is also the case with the sorption in phosphonic re sin [2J, is accompanied by the endo effect. The sorbative complexes,stability and the changes of en thalpies of sorption in polyampholytes, on the one hand, must follow the Irving-Williams order,and on the other hand, with the ions' effective charde in this order, the quota of the ionic in teraction between the metal ions and ligand groups must increse. •vs is obvious from Fig.2 and Fig.5, with in a large2rang|+of £ INVESTIGATION OF THE IONS ADSORPTION ON SOLID BOLD SURFACE IN MOLTEN SALTS Yu.G.Pastukhov ,V.P.Stepanov ,S.I.Dokashenko, V.3 Beljaev Institute of Electrochemistry of Ural Department of the Academy of Science U.S.S.R. The surfase of solid gold electrode contacting with molten salt electrolyte Has investigated by 3 methods si- measuring of the weight of menis!< 1) allowing to calculate the interfacial ene rgy (ДО),2- impedantSp and 3- estance (differencial interfacial tention f 2,3) techniquel hO - AP cosB С = ge/вЕ Щ/ЦЕ. - -q-gq/ffV > dV » 0s/s , where ДР - difference of weight per unit menlsk length , в - the angle of wetting , С - capacitence of charged boundary , Б and q - den sity of free and full charge, E - electrode potential , temperatu re (T>, frequence (f) and salt composition were varied. The gold electrode may be considered to be palarizable at T near melting points of alkali metal halides in wide interval of E. The electro- capillary curves (ECC) have a Maximum or landing , PZC probably occurs in this area, the (J-magnitude decreases under cathodic po larization for all salts , and it decreases under anodic polariza tion for LiCl and NaCl and increases for othrs alkaly chlorides . The double layer capacity vs E curves have a wide minimum with potential -value mare negative that PZC and a choilder or second minimum with positive charge of gold electrode , this minimum is very deep var molten NaCl.The estance -curves at that conditions have 3 special poin-s (ZE>, where the magnitude of full charge density influenced by the elastic surface deformation passes thro ugh zero chaging the polarity . The E of cathodic ZE takes place in the region of cation discharge and depends on the nature of alkaly cation , T and f. The middle ZE occurs in region of maximum ECC, and the third - in the region of anion discharge . The incre asing of anion size shifts both the E of this two anodic ZE and anodic branches of ECC to more negative values . The experimental S results may give evidence about essential influence of the adsorp tion of melt components in the interfac.ial layer on its state and properties. It may be proposed the existence of nonelectrostatic adsortptian of anions an the gold surface which increases with lowing of T, with growing of hath anion size and positive charge on metal. The formation of зtable bondes of anions and gold atoms with the partial charge transfer leads to deteriorating of the wetting, decreasing of the capacity and rising of the resistance of the boundary. The substitution of one cation of salt to other, with smaller size , diminishes the adsorption of anions on gold owing to Its contrpolarizing influence on- anion. The growing of T results in an activation of the electrode processes of cations and anions discharge and reducing of the interval o+ f-olarizabili- ty. In addition the wetting gradually improves and the shape of curves changes : the anodic minimum on C-E curves transform into shoulder ami then disappeares, the value of full charge regisred by estance methods decreases, two anodic' ZE шгв merging , and then disappear by T~1300K| only cathodic ZE remains. These are probably connected with weakening Of the adsorption processes. REFERENCES. l>V.S.BelJaBV,n.V.Smirnov, V.P.Btepanov,Rasplavy N1C19B7) , ЮЗ. 2>Yu.G.Pa3tukhDV,V.P.Stepanov,Dalelady AN SSSR , v.S07,N5(1989) ,648. 3) A.Ya. Bokhshtein. The surface tention of solids and adsorpti on,Moscow, 1976. 2 ЛСГ Ли - HaCI T=108SK i-current density, 1, mA/sn* 2-change of До-, mR/m 3-specific capaci ty, mlcFxs»* lOOWfe 1,2,3-stady state Measurements ^-magnitude of esfance 5 KHz ,50 mV/B THERMODYNAMIC ASPECTS OF SOLVATION AND SORPTION IN THE SOLUTIONS OF IONOGENIC DYES. A.G.Zakharov Institute of Nonaqueous Solutions Chemistry USSR Academy of Sciences.Ivanovo,USSR. Dissolution and solvation of ionogenic dyes has a number of peculiarities compared to inorganic and simpliest organic elec trolytes. These peculiarities are determined by the presence of a large organic ion containing different functional groups. The en- thalpic. entropic characteristics of dissolution of a series of ionogenic dyes in water, watei—organic and water-salt solution are given: Considered and discussed is the character and peculia rities of the change in the thermodynamic characteristics of dis- solunion (solvation) of the compounds noted. The presence of large poly-functional organic ions leads to substantial changes in the properties of solvent, to extremal dependences of the thermodyna mic characteristics in mixed solvents. The state of dyes in solution exerts a direct influence of their sorption by fibre. The interrelation between the' thermody namic characteristics (activity coefficients. Gibbs free energies) of dye solutions and adsorption phase at adsorption on cotton fib re is given. The mechanism of the formation of the adsorption solu tion and the rolt of inorganic electrolytes that comes to the ac tion on the solvation shells of dyes and fibres is discussed on the base of the theory of volumetric filling of pores. The experimental results are obtained using the thermocheroical and potenioimetric investigation methods. TWO-PHASE COEXISTENCE FOR LENNARD-JONES FLUID IN THIN SLIT PORES WITH HARD WALLS E.K.Plotrovskaya, E.N.Rrodskaya Leningrad State University, Leningrad, USSR Experimental and theoretical invevStigation of the thermodynamic properties and s'.ractural characteristics of systems at the solid surfaces and especially In pores is a difficult and not always correctly solved prcblem. Therefore special attention is paid to computer simulations ol (.Vie systems at the solid surfaces and in pores. In the present paper Monte Carlo simulation of Lennard-Jones fluid in the slit pores with the completely unwetted walls were held. We determinated the value of the chemical potential for the appearenoe of the meniscus between liquid and vapor phases. The calculations were held, for threa thickness of the film - H = 12o , 6c , and 3o (where a is the oaragerer of Lennard-Jones potential). So we were investigating theu vame of Laplace pressure Tor which a liquid film form.? in a pore of given thickness. The calculated value of Laplace pressure' allown us to estimate surface tension 7 by means of the following equation for a flat pore PL = 27/H. Such calculation for liquid films between hard walls were not performed before. The procedure proposed in [1] for molecular simulation of capillary condensation in cylindrical pores with wetted walls «fay ured in thesv calculations.This procedure is connected with calculations oi the dependence of grand potential 0 on cherical potential u. for vapour and liquid branches of adsorption isotherms. The point of phase equilibrium may be found as a crossing point of two brandies 0(ц). we calculated Q(p.) for the liquid and gaseous ranges of adsorption Isotherm at T=90K accord:!rig to procedure 11]. The crossing of these curves gives the value of the ohemicaJ potential corresponding to the vapour-liquid transition. It :,/aa p. •--•-y,r> 2 and Г"ош the l/t,ii»i-.e; euumln.] -p. find a surface tension 7=0.75eo~ the v;-.Lue of which is a olt iov:er than that calculated previously by MC simulation (Klrkwood-frtff equation) i3) which was 7 =0.85eo . REFERENCES 1. Peterson fU'., Cu'.v-'S K.E. Mole.c.l'hys. M (1987) 215. 2. Впх'лкауа Х.Х., P.unanov АЛ. J.Interface Colj-Sci.62 (1977) 542 3. Brodskaya E.N., Piotrovskaya E.bi Vestnlk LC.U(tn Russian) 4 (1989) 43 Г79 THE WORK OF FORMATION AND ELECTRIC PROPERTIES OP WATER CLUSTERS WITH AN ION FROM MOLECULAR DYNAMICS SIMULATION E.N.Brodskaya, A.I.Rusanov Leningrad State University, Leningrad, USSR Small water clusters forming around an immobile ion have been simulated by the molecular dynamics. Clusters contained 14 or 26 water molecules and the K+ or the CI . The ST2 and TIP4P water models were used in order to obtain the results not connected with' the concrete model. The first considered problem concerned the preferable condensation of water on the charged cores. The thermodynamics И1 points out that the difference of the work of liquid nuciea formation AW on the oppositely charged ions is proportional to the surface potential 01 liquid AV and does not depend on the nucleous size. So this fact is of special importance for the very small clusters and the most correct test or it may be done with the help of the simulation. We obtained the local normal pressure PN(r) in the cluster and then calculated the excess grand thermodynamic potential (the work of formation) of cluster. Earlier [21 we calculated the surface potential for the ST2 water and obtained at 290K AV =-0.12V. Consequently the ST2 water must condense preferably on the cation. As the thermodynamic conclusion [11 concerns the charged cores which are Identical each other in all aspects but charge sign the clusters with the К and the К were compared. We obtained that the work of formation for the clusters with 26 molecules and the К is smaller than for the К . That means that the ST2 water will condense on the К with the most probability. The second question is about the local electric characteristics in the vicinity of an Ion. In the theory of the electrolyte solution the assumption about the decrease of the dielectric permitivity near an Ion often used to explain the enthalpy of nydratlon. From physical point of view it is necessary to know the local electric field. At present such information may be gained by means of the computer simulation only. We calculated the electric potential ф(г) as a mean Coulomb potential on the sphere or the radius r. The most important observation is that the local potential is an oscillatory function of r. In the local approach it would mean that the dielectric permitivity may be negative. Consequently this approach can not be used here. Besides this potential acting on the probe point charge the field 1ц (г) and the potential ф1(г) acting on one water molecule from an ion and the other molecules were calculated also. We obtained that the intensity of h (r) in the first and second hydration shells is much smaller than the intensity of the Coulomb field of the central ion. These results allow to estimate the contribution of the water molecules into the local electric field near an ion. REFERENCES I.A.I.Rusanov, F.M.Kuni, The Colloid Journal (USSR) 44 (1982) 934. 2.E.N.Brodskaya, A.I.Rusanov, Molec.Phys.62 (1987) 251. CALCULATION OF THE SURFACE CONTRIBUTION INTO THE THERMODYNAMIC CHARACTERISTICS OF LAYERED CRISTAlS I.A.Gospodarev and E.S.Syrkin Institute for Low Temperature Physics and Engineering Ukr.SSR Academy of Sciences, Kharkov, USSR The unusual character of the bonding forces in highly anisotro pic crlstals manifests Itself In the temperature dependence of the thermodynamic characteristics of these materials Ml. Large anlso- tropy can be due In particular to an essential difference of the Intralayer chemical bond from the lnterlayer one. We analyze the role of the surface 1л this type of compounds. For a particular model of a highly anisotropic crysyal the temperature dependences of the surface free energy and of the contribution of the surface Into the heat capacity have been obtained. The calculation method employed [2 J enables consideration of models of a crlstal and the surface close to real structures and trace the evolution of these characteristics with changing parame ters of the slstem. Analysis of the chenge in the surface heat capacity of the crystal made it possible to separate distinguish effects due to the surface and to the character of the interatomic Interaction. The effect of the off-central interaction (the flexu- ral rigidity of layers) which increases with the anisotropy of the slstem. The figure shows the results of the calculation of the surface contribution to the heat capacity of an isotropic (1) and a highly anisotropic (2) cristal. At low temperatures the surface heat capacity of highly anisotropic cristals is much larger than that of isotropic; as temperature rises, this relationship rever ses. The maximum of the calculated surface contribution is displac ed towards lower temperatures as anisotropy increases, and its position does not depend on tne surface condition. Consideration for the off- central interaction causes decrease of the maximum of ЛС(Т) (the dashed line In figure). The effect of the impurity surface mono layer and the surface distortion on the thermodynamic characteristics is analized. It is of mach interest to study into the surface characteris tics of highly anisotropic cristals with a complicated lattice. We have considered the lattice consisting of alternating layers with unequal atom masses as a model of such crystals. The contribution of the surface Into the lowe temperature thermodynamics will natu- 181 rally depend on whether the surface consists of atoms of the light or the heavy sublattlce. It Is shown that If the crlstal surface Is formed by a layer of atoms of the light sublattlce, the temperature dependence of the surface contribution to the heat capacity in the said model is practically Independent of the relationship between masses of atoms of the sublattices. If the surface Is formed by atoms of the heavy sublattlce, then the maximum of ДС(Т) Is displa ced to lower temperatures with encreaslng difference of the masses of atoms of the sublattices. Such a surface can give a considerable contribution to the heat capacity of a highly anisotropic crlstal, even for small S/V. The character of the dependences obtained Is explained on the basis of the specific features of the phonon spectra of the systems under consideration. А С 1.0 • • \l 0.5 ^ 2 *>v /V -•» 1 l_ 1. 0.1 0.2 T / 9 FIG. 1. Temperature dependence of surface heat capacity for crlstals with various degrees of anlsotropy. REFERENCES i) E.S.Syrcin and S.B.Feodosyev, Fiz. Nlzk. Temp. (1985) 1001 2) V.I.Feresada, Flz. Kond. Sost. (1968) 172 162 STATISTICAL THERMODTNAMICS OP SURFACE EFFECTS AHD CRITICAL INDICES 1.1. Harkevich Dept. of Phys., S.M.Kirov Byelorussian Technological Institute, Minsk, bSSIi A consistent statistical theory has been developed for des cription of the structural and thermodynamic properties of inho- mogeneous systems. A heterogeneous system, consisting of micro- drops in a sas phase or of bubbles in a liquid phase can.be an example of such system. A chain of equations for the correlation functions of conditional distributions and Gibbs - Helmholta equation have yielded the statistical expression for the effect ive Hamiltonian in Landau - Livshits sense: $•{/]' -j(Sfctr+kTj[j>en/>+(i-f)en(s-/)Wr +• н/}. CD Here fit is the chemical potential,/} (7) is the unary density field of the system, к is the Boltzmann constant, T is the tempe rature, Ff } is the known functional of the density field: Fffl = -trff &(n if}) JF+i&ffb» (г, <*', if}) №P)JFJPw where the auxiliary functionais Q and f are expressed in integral fashion in terms of the molecule interaction potential of the system andflo(?,rO is the binary density of inhomogeneous system. Varying tl) in the unary density p. (r), we arrive at the equa tion for equilibrium density field or the heterogeneous system: r SnfCrJ - eKU-f(r})-Ct(rAf 0.6 V2 ом \ / as У I . г _i_ — — 8 i6 МГ Fig. 1. Density profiles at different values of inner phase densi ty p., for the bubble-liquid (1t jS-| = 0.184) and drop-gas (2, p-, = 0.8*1*) systems In Fig. 2 the curves'of taigential Pp «ad norma?. Рл press ure tensor components at temperature в a i are given. 1 1— — 14 ^ OJSS " ' в 46 Z* Pig. 2. Curves lz aDi рл for *Qe bubble-liquid system at J>** 0.484 <1) and drop-gas system at p-| = 0.814 (2). The approximate expression for the surface tension at the spherical phase Interface has the form со where Pg- (0) is the component of Pj- value at the spherical nuc leus center, and P,. is the pressure of the innen spherical hypo- tuetic homogeneous phase, coexisting, with the outer homogeneous phase оГ density 5? at pressure P„. At large (Rj — «*») and email (8f0) radii of the Gibbs sur face tension, expression (4) coincides with the known thermodyna mic relations. The pressures P-j and Pj are related to the surface tension 6" by the Kelvin equation: k*iB.3. Plot of 6* versus Rs for a bubble (1) and drop (2) at the temperature © = 1; 5 and 4, asymptotic relations 5" = 6(R* ) Implementation of the idea of abridged description in the "'.«actuation theory allows the critical indices and amplitudes to b; calculated without using the gradient expressions and without ; jslug to the space of wave vectors. 104 NON-&tUn,IBiUUM THERMODYNAMICS IN THE PROCESS OF REDUCTIVB SORPTION Yu.A.Tarasenko, G.V.Reznik, N.Ye.Tevtuehenko Sorption Department of Institute of General and Inorganik Chemistry, Kiev The process of reductive sorption (RS) is the electrochemical currentlees reduction of positive metal ions during their sorption from aqueous solutions /I/ on active carbons (AC). As the model of R6, we used electrochemical model, applying thermodynamics of irre versible processes (TIP). The reason for that is due to the fact that the RS eyeterns are the non-equilibrium and open. These sys tems ровевв physically and chemically non-uniform surface. That is why our mathematical model is based on the "Neccessary conditions of stationary state stability" /2/ and use the integral equations, describing the momentary value of concentration and the evolution of all parameters /3/. We worked out the closed system of equations for calculations of parameters for RS in stationary state and explained their time dependence. We manage to calculate the population degree of the outer grain surface for the ЛС with metals, the operating surface potentials of AC, the current densities of the cathodik and anodik reactions as well as the time dependences of these parameters. Using such an approach, we described stationary states and kinetics of RS.As the result, some control algorithms were deter mined . 1. Xu.Torasenko, K.ouprunenko, V.Uudarenko et.al //In: Carbon - 90. International carbon conference.- Paris,- I990.- P.52 -5"» 2. Yu.Tarasenko, G.Reznik, A.Bagrejev /Ukr. Chen. Journ.- 1969.- 55.- N 3.- P. 2*9 - 255. 3. Yu.Tarasenko, S.Antonov, A.Bagrejev, G.Reenik //Ukr. Chesu Journ. 1969.- 55.- N II.- P. 1179 - IIS3. 1U; SORPTION PROCESSE'S CALORIMETRY ON ACTIVE CARBONS A.A.Bagreev, Y.A.Tarasenko, V.V.Strelko Sorption Department of Institute of General and Inorganic Chemistry, Kiev USSR The energetic interaction of active carbons ( AC ) with halogen-ions and noble metals ions was investigated. Ion- exBhenge reactions and reductant sorption processes are typical for these systems. Ordinary they involve not only the formation of the surface-complexes with transfercharge, but also electro chemical reduction of ions to metalic state on carbon matrix. ' The synthetic AC SON of spherical shape and technical carbons BAU and SOT were used as sorbents. Thermal effects were mesured by means of flow-ealorimetric method using sorption microcalorimeter LKB - 2107 (Sweden ) in conditions when we noted the moistening, neutralisation-, the ion-exchange, the surface complexformation and the metal phase production heat effects. While examining interaction beetwln halogen-ions and AC it was estimated: the exothermic character of sorption, reversi bility of halogenides sorptions, selectivity of sorption from mixtures containing halogens and affinity series of anions towards the surface of AC ( P~< Cl"< Br~< T,~) , which correllated with the value of theis electron polarization. It was found,that reductant sorption processes of noble metals was the exothermic and irreversible, one. We calculated the surface oomplexformation and the formation of metallic phase heat effects in the systems,which corresponded to the formation of X - complexes of transition metals whith olefins and the heat effects for the phase change liquid - solid state, respec tively. So,the microcalorimetry method combined with the sorption and spectral methods permitted us to explain the selectivity of sorption and mechanism of interaction of halogen - ions and noble metall ions with active carbons. 1) Y.Tarasenko, K.Suprunenko, V.JXidarenko, A.Bagreev, T.Miroyuk In Carbon - 90, International Carbon Conference. Paris, 1990, p. 52-53. (Y.Tarnsenho.A.B^rsov.S.Lavriiieriko-Omet.H ?o:cr,.;l.-. Calorime -ry in :idaor?fcion and catalysis-.Uovooibirci, 19-°/J,p.29. It-Г NON- Bill ИЛ BRIUM THERMODYNAMICS APPLICABILITY IN CONJUGATE KLKCTROCHWUCAL REACTIONS ON THE NON-UNIFOBM SURFACE fi.V.Krzii'.k, S.P.Antonov, Yu.A.Tarasenko Sorption Department of Institute of General and Inorganik Chemistry, Kiev The extremal principles of the non-equilibrium thermodynamics are efficient research instruments in studies of stationary states in the open non-equilibrium eyeterns. These principles, however, have the correct mathematical proof only in uniform systems. In the pre sent report the method is proposed, which allows the mentioned prin ciples to be applied to the explanation of electrochemical processes on the physically and chemically non-uniform surface The considera tion is performed for the case, where the conjugate electrochemical react-'one are distributed between the different surface regions, these regions areas varying under the action of the irreversible processes. The ineth- i ,iastification is carried out for short-circuited electrochemicfll systems with the contact replacement of metals. It was assumed that irreversible fluxes are the linear functions of the thermodynamical forces. As a result, the neccessary conditions of stationary state stability were estimated, and a closed system of equations was obtained (such a system cannot be developed in any other way). Then, the stationary potentials were calculated for ca- thodik and anodik regions, as well as the coating porosity and the intensity of corrosion process, proceeding under the coating. The correctness of the results was verificated by using experimental and logical teste. 'I'll.' piopoeod approach generality and it's wide applicability were demonstrated. The method is suitable for solving different problems, connected with the control algorithms establishing for non-umIorm electrochemical systems. These problems involve, in par ticular, «"orr-.i inn, ittanding loss of chemical cells, electroplating, reductive sorption enc. It/7 THERLODmAtilCS OF CHROLATOGRAPiilC SELECTIVITY OF biXXED i.£bOFiiASiiS K.S.Vigdergauz. A.V.Bulanova Department of Chemistry. Kuibyshev Statn University, oainarn, USSR. One of the unique properties of liquid crystals leading to their broad application in various spheres of science and techni que, is their ability for seletive dissolution of subtances with close structure. This is the reason of high chromatographic selec tivity of mesophases during complex separations. Liquid crystal selectivity in the analysis of structural, iso mers "may be considerably increased by the application of binary and more complex liquid crystal mixtures as chromatographic stati onary phases. Selectivity estimation may be carried out by deter mination of sorption thermodynamic characteristics of separated co mpounds • The purpose of this paper has been investigation of sorption thermodynamics of compounds'with different chemical nature by mix tures of the most popular in chromatography liquid crystal statio nary phases p.p'-diethoxyazoxy benzene (DBA.B) and p.p'-methoxyetho- xyazoxy benzene (MEA.B). Experiments have been performed on ohromatograph LKhl-J-80 '"6 with the thermal conductivity detector at different temperatures. Mixtures of DEAB and JAEAB of various composition have been prepa red. Differential thermal analysis of the mixture has been fulfil led according to the techniquefl]. N.paraffins and iicReynolds' sta ndards (benzene, butanol-li- pentanone-2» nitropropane. pyridin) moat fully characterizing stationary phases chromatographic pro perties, and m- and p-xylenes have been uued as eolutes. Absolute specific retention volume (V ) of solutest partition coefficient (K) equal to the ratio of solute concentration 0. in a stationary liquid (gr/ml) to its concentration С in a gas phase, partial molar free enthalpy of sorption iS have been calculated. Analysis of correlations between thermodynamic characteris tics and binary mixture composition has shown that there are spe cific interactions between ingredients, thermal analysis proved that the mixture containing DEAb in the range of 2C.7- 35.0 molar % is close in its properties to eutectic one. Binary stationary phase selectivity (G>) towards m- and p- xylenes which has been estimated by the ratio of partition coeffi cients in the mentioned range of DKAB in a mixture sharply incre ases. It is 1.09 and 1.11 for DEAB and ьЕАВ* correspondingly, and it is 1.17 for their mi xture with 28.7-35.0 molar % of 1ЖАБ. REFERENCES 1) b.Bardukov, L.binejev, Intercollcge Trans.. Ivanovo, 19G0. ICO THE INb'LUBMOE Ob' INTEKPHASB BOUHDAxUES ON THJiriLODraAUICsi OJv GAS- CHUOMlTOGKAPHIC SOHPl'IOS 01' OWGANXC COMPOUNDS BY NEivA'ilG LIQUID CRYSTALS . L.A.Onuchak, w.S.Vigdergauzt G.V.Surzhikova Kuibyshev State University! Samara. USSR. As thermotropic liquid crystal utilization is mainly connec ted with the application of thin films on various supports f inves tigations of surface phenomena have a great theoretical and prac tical value. The task of quantitative investigation of the influence of film thickness and interphase boundaries on sorption thermodynamic parameters of organic compounds by nematic liquid crystals of the series of azoxy ethers (p.p'-azoxy phenetol (AOPh) and p«p'-raetho- xyethoxyazoxy benzene (MEAB) has been put forward for the first time. This aim has been achieved by comparison of gas-chromatogra phic sorption thermodynamic parameters obtained on packed columns with different liquid film thickness (form 20 to 200 nm) and diato- maceous supports with different surface chemistrys active Ш AW) and deactivated by means of acid wash (AW) and by means of silani- zation by hexamethyl disilazane (HltDS). Contribution of substance adsorp-»ion on gas- liquid crystal boundary (6,%) in sorption thermodynamic parameter value has been calculated-'on the baaie of adsorption static investigations per formed by the method of "pendant drop*. ^ Adsorption contribution on a liquid crystal- support (Q *%) interphase boundary baa been determined by substraction of the contributions of dissolution in a film and gas- liquid adsorption from the corresponding parameters. Gas- liquid crystal boundary most strongly influences sorp tion thermodynamics for all types of supports. This interphase boundary contribution value was found out to depend on the molecu lar nature of a solute and temperature, film thickness and type of support. It is especially great for columns prepared with the help of active supports (N AW). Evidently, strong specific inter actions between a polar croup located in the centre of an azoxy ether molecule and surface impurity metal atoms lead to high struc tural ordering and planar orientation of this class of liquid cry stals. This complicates penetration of incidental molecules into the film and liquid crystal- support interphase boundary (except for flat molecules with aromatic configuration). As enthalpy of gee-liquid adsorption considerably exceeds in absolute value en thalpy of sorption in volume, then, film thinning leads to the in crease of exothermic fi -contribution and to the growth of sorpti on sum enthalpy (^H| ) on active supports ( Slg.1). High-degree ordering of the nematic film structure on active supports and high sensitivity of gas- liquid crystal adsorption towards space con figuration of close aromatic meta- and pera-isomers leads to a greaterraeta-pare-aelectivity o f a given liquid-crystal eorbent. .. A lesser degree of the nematic film structure ordering on de • activated supports ( AW and HKDS) leads to the decrease of fi - eontributiou and sorbent neta-para-oelectivity. In this case aor- Й10? therinodynamic parameters depend to a lesser degree on film thickness. Comparison of Jf-contributione on liquid crystal-support inter- Phaae ourface into sorption thermodynamics is of particular interest Sownfr«Vh*°r"efl and PMC"C«1 viewpoint. Calculation have shown that о given interphase surface actually does not participate 189 in substance retention in a chromatographic column due to prefe rable adsorption of the molecules of the nemetic itself. Inciden tally! interaction between support and liquid crystal in the seri es Chromaton HMDS — ->Chromaton AW —* Chromaton К AW increases, while adsorption ability of organic compounds on liquid crystal- support interphase surface decreases. The investigation performed makes it possible to put forward the methods of control of selectivity and capacity properties of the column with liquid-crystal stationary phases by means of tempe rature factor! film thickness variation and support surface che mistry change. Figure 1. Dependence of standard molar enthalpy of gas-chromatog raphic sorption of n-alkanols on support impregnation percentage by p.p -methoxyethoxyazoxy benzene (film thickness changes from 44 to 280 nm, nematic phase. 378°-413eK) : 1- propanol.2- butanol. j-pentanol. 190 h.N. Marsh THC Source !• ile Database- Towards Automation in Physical Property Data KvnluaUon Abotmct The TRC Thermodynamic Hesearch Center has developed a large database (THC Source File) containing experimental data for the thermodynamic and physical properties of fluids and solids. Л particular feature of the database is that, where possible, the accuracy of the measured property has been assigned. The use of retrieval and other program!! to extract and automate the data evalution process to obtain evaluated thermophyeical property data will be described. 191 A IlbW METHOD OF STATISTICAL PROCESSING OF DATA OK 'J.m'RMOCHbMIoTRY Of OXXGEN ACID SALTS I.M. Zharsky, V.P. Glybine Dept. General and Inorganic Chemistry, Byelorussian Technolo gical Institute, Minsk 220630, USSB A comprehensive method is developed to estimate the confidence 4nd to predict the magnitudes of formation enthalpies of salts from oxides. It is based on applying the Lewis acid and base theory to interaction between different-nature chemical oxides /1/. The fol lowing aquation is obtained and describes thermochemistry of this interaction (per mol ef salt equivalent): ДГН °ox (298.15 K) = K(FA.*B) + В (1) лпоге F, and'Fn are the energy parameters of acid and base oxide forming^ salt, respectively; К is the factor correlating with a fchermochemical radius of salt anion; В is the acid oxide constant dependent on its nature. Numerical values of the parameters and constants of equation (1) are cited in Tables 1 and 2. These are based on the statistical • rocossing of the entire thermochomical data file of handbooks com piled by different teams at the High-Temperature Institute of the USSB Academy of Sciences and covering the data of a number of exten sive publications» The specific feature of the proposed system of parameters is associated with their self-coincidence. The correlati on coefficient r close to unity (Table 2) points to the fact that this model is valid and that the magnitudes of reaction enthalpies may be predicted, as well as the confidence of the available expe rimental data may be estimated. If there is soma file of tha experi mental data on formation enthalpies of oxygen acid salts not includ ed into Table. 2, then in this case, using even only the parameter PB , the data may be processed by the graphical method in construct ing the relations A H 2 r ox ( 98.15 Ю = f(FB). When three, as a minimum, rather confidence quantities ДгНох of any acid are available, t-his method yields numerical values of the parameter Рд, constants К and В of oxide forming this acid. The following relations and correlations are obtained to find these quantities» PA = 3.984.10"* (IA) (2) where IA is the ionic oxygen affinity of acid oxide per oxide mols F ( н (298 15 К B = Дг ох ' »/(АВН^). (З) In turn, AEH°x(kJ) = -31b + 10.9 PE,. (4) where PKj is the decimal logarithm of the first dissociation cons tant corresponding to the acid oxide with a reverse sign. 192 The factor К correlates with an ionic potential (z/ran) of salt anion asj К = -320.8 (й/raa + 1.32) (5) where z is the anion charge and гац is the thermochemical anion ra dius. Ив азэшпе it desirable that new data on AfH (298.15 K) of salts be checked for fulfilling the conditions K) t5 1 4^(298.15 K)9Xp - ДХХ(298.15 theor * ' kJ.mol" . Table 1 Values of the Parameter Fg of Oxides of Some Elements Oxide FB(+0.020) Oxide Fg(+0.027) Oxide Fg(+0.027) Oxide Fg(+0.035) As20 0.237 BeO 0.164 CdO 0.216 BaO Q.455 Ti20 0.334 CuO _ 0.16? FeO 0.220 HaO 0.620 Li20 0.470 HgO 0.159 P°0 0.232 AlgOj 0.168 Na20 0.633 5n0 0.172 MgO 0.246 *"e20* 0.160 K20 0.799 ZnO 0.174 MnO 0.260 Bi20, 0.230 Gl 285 Hb20 0.842 NiO 0.191 CaO 0.402 z°3 °* Cs20 0.856 CoO 0.205 SrO 0.484 LagO, 0.319 Table 2 Values of the Parameter F., Constants К and В of Some Acid Oxides Oxide Anion F«(±0.015) K, kJ B, kJ I N2°5 NOJ 0.620 -590.8 2.8 0.997 so3 so," 0.5^5 -701.9 -24.4 0,995 G02 so^ 0.392 -743.9 -1.8 0.980 a- 8.4 co2 co5 0.326 -769.9 0.996 10 7.2 *& зГ 0.520 -599.2 0.997 PpOc, »*• 0.356 -827.6 0.4 0.995 SiOg SiOjf 0.183 -957.9 30.3 0.995 (sio3)^- 0.302 -701.З 37.2 0.997 KEFEEENCE ' V.P. (rlybine, Energy parameters of a coordination-nonsaturated atom. Proc. 17th All-Uniou Chugaev Conference on Chemistry of Complex Compounds. Pt 2, Minsk, 1990, p. 270. 193 THE PROBLEM OF THE EFFICIENCY OF THERMODYNAMIC MODELING OF THE BEHAVIOR OF NATURAL AND POLLUTED WATERS. A.A.Slobodov Dept. of Physical Chemistry. Lensoviet Technological Institute. Leningrad 198013. USSR. The variety of types and compositions of natural waters- encourages the elaboration of.the methods of thermodynamic modeling and databases for analysis of chemical and phase transformations occurring in these systems. The presence of industrial pollutions makes the problem more complicated quantitatively and qualitatively. When solving the problem it is necessary, on the one hand, to ensure the completeness and the reliability of the initial thermodynamic information. On the other hand, the peculiarities of the representation of the composition of water and of the state variables based on the results of chemical analysis are to be taken into consideration, as well as the influence of the precipitation. Even the most powerful compute. programs are subject to a number of restrictions regarded the databases. the account for the reduction-oxidation reactions, the model of the sediment - aqueous solution interaction. The analysis of the existing data made it possible identify the principal chemical aqua forms, occurring in different types of surface and subterranean waters and also in sewage. In the course of the examination of existing thermodynamic data a base G and/or lo of self consistent data including Af 298 9" K-stability for the major aqua- and sedimentary compounds has been created. Theuo compounds are the aqua complexes of the alkali, alkaline-earth, heavy metals, etc. Carbonate, sulfate. chloride, hydrpxo- and other ions are used as ligands. Also taken in account are . the micro-, radioactive elements. components of biogenesis, etc. The elaborated method of modeling and analysis of chemical and phase transformation is equally adapted for the representation of the initial data in the form of analytical concentrations of the components as well as for the generalized characteristics of the water: its alkalinity, hardness. etc.. for considering the conservant and nonconservant additions, trace components, different gases.. The method is subject to no restrictions on the number of reduction-oxidation reactions. As a results of calculations analytical concentrations and activities of all possible components of aqueous system, the degrees of distribution of metals on ligands are obtained. The saturation conditions for all possible sediments are checked, the precipitating and dissolving phases, the quantitative characteristics of these phenomena are determined. The distribution of metals between the water and the precipitated phase is also calculated, etc. Mathematically it is so far the most efficient existing method. The method was implemented in a program complex EQSOL (in PL/I. FORTRAN. Pascal), a number of test problems . were solved to prove its validity. To illustrate this approach the results of the simulation of the behavior of surface waters in the region of the Chernobyl catastrophe are furnished. These results make possible the estimation and the prediction of environmental - and radiational situation'in this region. VM NEW EQUATIONS OF STATE FOH PHASE EQUILIBRIA CALCULATIONS N. A.Smirnova,A.G.Morachevsky Dept. of Chemistry, Leningrad State University, Leningrad 198904, USSR Calculations of thermodynamic properties of pure and mixed fluids and modelling of phase equilibria are problems of great importance in physical chemistry and chemical engineering. Un til the early seventies main attention vas paid to methods based on the use of separate models for vapour and liquid phases. This is a convenient approach in the case of moderate pressures but in modern chemical and petrochemical engineering there is a need to have quantitative methods for treatment of phase behaviour in a vide range of conditions including very high pressures, criti cal and supercritical temperatures. Such a treatment can be achi eved in principal vith equations of state (EOS) describing both liquid and vapour phases. This explains a great splash of the in terest to EOS during the last two decades. The work in the field is carried out also in the laboratory of the authors. In the com munication the state of art and new tendencies are discussed with special attention to the theoretical background and practi cal applications, of EOS. Many EOS'are successful in the description of light nonpo- lar or slightly polar components and now the main problem are fluids of a more complicated nature such as those including long- chained, polar or associating molecules. Among especially diffi cult but practically important systems one should name asymmet ric mixtures - systems where components differ significantly in molecular size and (or) polarity. Empirical modifications of cu bic EOS are proposed for such systems but there is a strong ten dency to find approaches which are theoretically more profound. A great progress in EOS is due to the use of perturbation theo ries and results of computer simulations for fluids. Models ta king into account association equilibria are proposed, free volu me effects for chained molecules are considered in EOS. Rather successful are approaches based on hole lattice models. Among these there is a quasichemical group contribution model (Smirno va, Victorov) universality and good predictive capabilities of which vere demonstrated for fluids of different chemical nature. Possibilities and shortcomings of the models are discussed and the results of their aplication for fluid phase equilibria predictions are compared. For the illustration mainly systems formed by the components of natural gases and oils are chosen, aqueous mixtures being also included. A wide range of conditions is considered, different types of phase diagrams are reproduced. 195 OJI THERMODYNAMICS OF REAL GASES AT HIGH PRESSURE (DEVIATION COEFFICIENT METHOD, ADIABATIC PROCESS) A.M.Rozen All Union Sci.Res.Inst, of Inorganic Materials, 123060, Moscow, Rogov str. 5, USSR As is known, in the adiabatic process the behaviour of ideal gas is described by Poisson equations: ц.н ,- P v * -const •, CVTM^/PO^; *-fe u; For a real gas these equations are incorrect, there are two adiabatic indices and neither is equal to the heat capacity ratio fit the constant pressure and volume. For the description of the solution deviations from the ideal solution laws it is convenient to use activity coefficients. Howe ver, in our instance since the thermodynamic equations contain P-V-T derivatives it is convenient to use deviation coefficients, i.e., P-V-T derivative ratios for real and ideal gases 1 . /Uir-#P/&Ur/fcPAr)w = CT/P#P/&U~;VX The deviation coefficients are calculated either by the gra phical differentiation of the P-V-T data or computed by the equat ion of state (conventionally as series of density and 1/T power). At reduced temperature T<. 2 and pressure 3T-tf. 80 ^HT is less 4 ^ while jLt-p and. fUo- are more than unity (for the typical curves see fig.1). At the critical point ^Л* Р and Mr approach infinity t while /ju retains the finrti value (<^ v,c= 6-8); with a Temperature rise ^u_- -*1; Fig.1. Deviation coefficients vs pressure a) /Д-р and Mir of nitrogen at a pressure up to 1000 atm., b) хЛу (in the generalized coordinates) 1УС Taking account of the deviation coefficients some thermody namic equations can be written down cJS-C^dUT-fypdG*? i Ce-Cv^p/V (3) For the adiabatic process (dS-O) instead of equations (1) where the volume (Kff) and temperature ("JtD indices of the adia batic process will be > /.. n , л L , j where С x>-id"cP _RMP is the heat capacity of the process at the constant ideal volume (i.e., the process in which the pressure grows proportionally to the temperature, P—T1 while at the con stant real volume P^T^*1" ). since C ia>Ce- -C> -R,u.p|U^,£A-K. On the contrary, the volume index Kv v is usually more than К and grows intensively with pressure (fig.2). At the critical point the temperature index remains finitesTe-e- M+/i M* -0-7/6-1,16, the ratio K«Cj> /Cir approaches the infinity while the volume index K-v^aR^v- Z./CV becomes nil (in l£l it was not yet clear as it was , unknown at that time that C^-^ee )• •» = P V/ftTa»>cl'£c»0lZS>C>3. Vf0eC »! Щ. л»* ^ ISO f^5 V5 w4*-^ e 6 ON POSSmrUTY OF ORDKRINO IN ANION SUBI.ATTICE OF Bi-Sr-Ca-Cu-O SYSTEM K.Yu.Shunyaev*,C.Carel** •Institute of Metal lurge, Academy of Science of I'SSR.Ural Department .Amundsena st. 101 , 620 2 1 9 ,OSP-R ! 2 .Sverdlovsk , 1'SSR **Universite de Rennes I.LaboratoJre de Cr I sta 1 lophitni e . Campus de Beaulleu,35042 Rennes Cedex,France •The BI -Sr-Ca-Cu-O system Is eharac t er I r.ed by cations of different types. Ions of changeable valency and the possible anion vacancies. The distribution on the crystalline lattice sites can differentiate from the chaotic one. The ordering (the short-range or the long-range one) Influences the eleetrophysical system propert i es. The most sublattices, which can be seen in the lattice of the given system, are the simple' square lattices. The analysis of the possible ordered structure types and the construction of the statistical ordering models for the lattices of the kind Is not difficult. We can obtain easily the expression to calculate the critical temperature of phase transition "order-disorder" in the different approximations, from the simplest Bragg-WI11 lams approximation upto the cluster variation method. Speaking of ordering we ean consider firstly the oxigen sublatticp, which can be buflded from two neighbour planes with SrO and CnO. It contains crystal1ographically non-equivalent sites and does not have the simple analogues among the lattices usually considered as the examples for the ordering theory development. This work Is devoted to the study of ordering on the oxigen sublattlce with non-equivalent sites in the Brngg-Wiiiiams approximation. The lattice under consideration can he divided into the three sub-lattices, each containing equal number nf sites. The ordered structure is characterized by the two order parameters.The phase transition on one of the parameters does not take place in common case since the considered lattice consists nf the energetically nonequivalent sites.The equation systems яге derived to determine the critical temperature and the long-range order parameters 4,(1.'3*4, *TJ2-3) (2lJj-6)AE, * rj,AF, 'ДРЯ eXP : < 1.^-4, Нв-Ч,-Ч2> * kT 4,f 1 -'S + rij^rij-S) (2ч2-'>21-6)ДЕ, ехр П-'3-г1,Н6--пгч2> ' KT ~ JJ.,4, - order parameters, AEj.uE, - energetical parameters, 6 - consentration of second compound 198 EQUATION OF STATE FOR SUBSTANCES WITH LAMBDA TRANSFORMATION P.I.DorogokupetB Institute of Earth Crust, Irkutsk, 664033, USSR The problems of the representation of thermodynamic properties at high temperature and hi 3I1 ргеввиге and the computation of the phase diagram for substanoes that have the lambda type anomaly in the isobario heat oapacity, thermal expansion coefficient and isothermal bulk modulus have been discussed in this paper. Various equations of etate have been adopted in oaloulating thermodynamic properties and phase diagrams for substanoes with firet order transformation (see, for example {Fernandez Guillermet et al., 1985; Fei, Saxena, 1986; Kuskov, 19S7; Dorogokupets et al., 1989; Plymate, Stout, 1989] et al.) and it presents no special problems. However, the substances having phase transitions of the mixed type with lambda anomalies in heat oapaoity or volume funotions require a different approaoh. The term of the jT/Ci-T)0-3 type, where i and j are the fitting parameters, is substituted in the temperature-dependent equation to express the anomalous isobario heat capacity and the thermal expansion coefficient. The i parameter is numerically close to the phase transition temperature (T«) and it is in the range of 0.1<|i-Tj. |<10, where i>T|. is for the low temperature phase and i THERMODYNAMICS OF FRACTAL STRUCTURF.r.. U.S.PERVOV Dept. of General and Physical i:in->«ist.ryr Moscow Institute of Chemical Engineer irnj» K.Marx st.»21/4» Moscow (ЗЗГ--1.0788 4 r USSR. Fractal theory «ay be used for a description of solids with characteristic structural uncertain!.у such as solid gels (silicagels» aluuagels and others)! some badly crystallizing molecular complexes» special ultradispersive powders* aggregations with the system unregulnting of a crystal lattice and at set. It is proposed the thermodynamic interpretation of the specific substance tendency to fractal structure-: formation (tipe of Mitten-Sander clusters) at un aggregation from vapours. The calculation basis are the thermodynamic chat actoristics of molecular formes at the saturated vapour. It is considered inorganic compounds such 05 fluoride» chloro-f Ьгомо-г oxo- and thio-substituted fluoride molibdenum and tungsten at the lower valency. Mass-spectromatr iir vapour analysis of this substencee» its magnetic and structural propertins point to ones are different polymers and polymerisation is caused-by a possibility of the change of the central metul atom coordination by means of bridge bond forming in the main. At the certainly condition its aggregation may be on a model of the Eneruylmse particle sticking» corresponding to the fractal mechanism. As at fractal aggregation structures of branched chains with the certain significance of a fractal dimension and a coordination number are? realised ones should correspond to the thermodynamic probability of a building of certain polymeric forms or form.collection. Thus a problem comes to determing af such m^tastable state thermodynamic characteristics of bridge ligande» an influence of metal valency» a substitution of fluorine by chlorine» bromine» oxygen or sulphur are estimated for the mentioned substances. The additive scheme using for an atom and a bond energy at a different coordination leads to "coordination lability" enthalpy of this compounds. It is proposed the Method of an «sti.mutinn of a fractal aggregation energy barrier» which is the difference between enthalpic characteristics af the demanded meta^tabl•• structure and anc at the "general state". Calculation is shown to correspond to experimental data. 200 THE PROBLEM OF SOLID-MEDIUM EQUILIBRIUM ACHIEVEMENT i.V.Melikhov M.V.Lomonosov Moscow State University, Moscow Solid-medium thermodynamic equilibrium is usually achieved with so great difficulties that all thermodynamic data must be completed with the information on the degree of proximity to equilibrium for the system under investigation. The indication on the proximity of measured system parameters to equilibrium ones (equilibrium criterion) could be found by solving the equation for the state of solid dependence on the change of medium properties. The equilibrium criterion has been found for two methods of equilibrium achieve ment. For the method of stationary exposure there was determined the ( P - T - X ) level beyond which the divergence between measured and equilibrium parameters exceeds the permissible limit for a given exposure time. There were established the limiting stationary flows of substances and energy into the system that reduce the equilibrium achievement time without significant influence on equilibrium para meters. For the method considerily the system under periodically changing external conditions there were found the limiting ampli tudes and oscillation frequencies which do not reduce the equilib rium criterion. It was shown.that during stationary exposure the metastable states reachable "from above" and "from below" can be formed with low equilibrium criterion. The methods of demonstrating the metastable states .tonequilibrium (cycles method, the method of solid perticles habit variation) are presented. 2CI THERMODYNAMIC MODELS OF OXIDE DISSOLUTION PROCESSES IN HALOGENIDE MELTS. V. N. Nekrasov, N. M. Barbin, L. E. Ivanovsky Institute of Electrochemistry. Ural Department of the USSR Academy of Sciences, Sverdlovsk, 620219, the USSR. Ionics salt melts such as the halogenides of alkaline and al kaline-earth metals and the solutions of gaseous and solid substan ces in them as well which form during dissolution the molecular or ionic complex groups and associates different in nature and bin ding energy are an interesting subject of inquiry. Various equili brium and kinetic methods can be used to study such systems. The paper deals with the two possible thermodynamic dissolu tion models, oxide solutions of alkaline-earth metals CCaO, SrO, BaO) in the equimolar NaCl-KGl melt are taken as an axample. The supposed dissociative nature of the solid oxide to soluti on transition MeOsolid= Me^ssolved+0|issoived may be characteri zed by the product of solubility CPS) PSCMeO) = [Ме2+ИОа ] = [Me OJ2, where (MeOJ is an equilibrium molar fraction of the dis solved oxide under the given conductions. In the first (physical) model the examined geteroqenous equi librium of solid oxide - gomogeneous melt is discribed as follows Gsolid= G°liguid+ MMa^+.ap-) = Gliquid+ RTInPSCMeO) + КИпСг^-Го2"0 (1) By introducing the standard thermodynamic functions AG£is = RTlnPS(MeO), AG£hase irans = GJ^- %оШ, *g*» - RTlnC^. Где-), we transform CI) to the equation *Gdis= AG°Dhase trans, .•AGPSf (2) The values of AG^gg trans are calculated by the enthalpy and en tropy constituents using the thermodynamic cycle: Csolid substan- ce)T •» Csolid substance)T •» (Liquid)T •• (supercooled 'exp 'melting 'melting liquid)T and the thermodynamic data known. Applying the resuits exp of the these calculations and experimental data to AGdjS the valu es of AGPJjys CyPhvs) are estimated. By the second (chemical) mcael the dissolution is examined as a chemical reaction between the Mex0 CMe:0 - CaO, SrO or BaO) oxi de and the MenCl (MenCl - NaCl and KC1) chloride and the thermo dynamic pattern assumes the following form 3 «^ЧоШ " G'CMe^OiiqMe'Cl, liq) • RTlnCa^io.a^) = х : = G'CMe^C^ Ме С1г и ) + RTlnPS(Me 0) • RTLnCy^nQ.^i^ ) * 2 2 (3) . oxide Assumin thee a sliqui a standard phasde conditioits representation of the beinn ign thdissolutioe form ofn Me'purOe 202 liquid Me110 and Me1CI components. The product of their molar fractions will coincide in magnitude with the product of solubi lity of alkaline-earth metal oxide. Denote the last member in the second part of the expression C3) on the right as ASgjJ|m and the Gibbs energies difference of standard conditions of the being dis Tne numericai solved oxide in liquid and solid phases as Дб£пег value of the last observable will be estimated by the thermodyna mic calculations according to the equation (4) M^solid + 2MeIlG1liq =Me "°liq+ *Ч liq (« The relation C3) is analogous in form with the expression C2) AGdis »AG chem + <Г <» The calculations by the equations C4.5) enable to find the values of AG°^m (гспеП1) that characterize the interaction of the dissolved oxide Mea+, 0a~ ions with species of its solution in the NaCl-KCl melt as compared with their interaction in the liquid Men0 Cfor the oxide ion) and MeICl Cfor the alkaline-earth metal z г cation). The derived calculattion results are given in the table.Their analysis shows that, on the one hand the interaction energy of the 0a~ and Мег+ ions with the solution species is higher than that in the liquid Me**0 and VtexQ\ mediaCthe negative UG^m values point to this fact). On the othez r hand,this intaraction energy is weaker then that in the liquid Me*0 that is observed from tne positive values. One may assune the definite coordination bond con- servation of the Me3 and 0* species during the oxide dissolution in the chloride melt. This view point is verified by the spectros copic Investigations. The particular values of the observables gi ven in the table reveal the changes in the thermodynamic equili brium as the solution composition and temperature changes occur. &Gphys yphys AGchem yChem T.K uG AG AG au diS ph.tr. chem exc kJ/moi kJ/moi CaU 1000 140, г П.4 128,8 5,3.10" 300,2 -160,0 4,4.10"* 1100 144,2 12,5 131,7 1,8.10е 298,9 -154,6 4,5.10'" SrO 1000 106,3 28,6 77,7 1,1.10* 228,8 -122,6 4,0.10"'' 1100 107,3 28,5 78,8 5,6.10* 228,8 -121,0 1,8.10"" BaO 1000 92,3 23,0 69,3 4,2.103 188, P - 96,2 9,4.10"" 1100 92,4 22,2 70,2 2,2.103 189,3 - 96,9 2.5.10"8 203 CHEMICAL THERMODYNAMICS OP KACR0DEKECT5 Hi CRYSTALS. V. B. Fedoseev Branch of Machine Science Institute 11334 Academy of Science, Hizhny Novgorod, Belinskogo, 85. In the theory of dislocation exist the estimation that in the condition of th!ermodynamic equilibrium the single crystal must; contain less then 10" dislocation in 1 cm . In this communication is•shown, that this extraordinary num ber is a result of a serious muddle in the thermodynamic notions and nonoorrect construction Of Gibbs-distribution. In the reversible process chemical thermodynamics produced the estimation of dislocation loops density,, edge dislocation and pores in single and polycrystals of same metals. The results of this estimation discribe the density and dis - trribution of defects per sizes at the different temperatures, hydrostatic pressure and the grain siees. This estimation corres ponds to the experimental values of dislocation density in annea ling materials and gives same regularities of crystal dislocation structure. The function of defects distribution per sizes has' maximum, which determined by the elasticity properties of material, the type of defect and thermodynamic condition. The dislocation density rises and maximum of distribution function per sizes displaces to the small sizes due to temperrture rising. The rising cf hydrostatic precure initiates the decreasing of small sizes defect» density. The density of edge dislocation near the crystal surface lar ge then in crystal volume. Under condition of temperature rising the distribution of edge dislocation near the surface have some evolution, which can be interprotate as phase transition, ob served experimentaly in surface melting of crystal. As a result of this consideration it is possible to produce the statement, that crystal defect structure can be vvell discribed by the ordinary methods of equilibrium chemical thermodynamics. This fact can be usefull in the investigation of connection "chemical composition - structure - physical properties". 204 CALCULATION OF THERMODYNAMIC PROPERTIES OF MULTICOMPONENT DISORDERED SOLID SOLUTIONS FROM THE FIRST PRINCIPLES V.A.Krashanlnln Institute of Metallurgy, Ural Dept. of the USSR Academy of Sciences. In this work we propose the calculation scheme of the free energy and the other thermodynamic properties of the multlcomponent disordered solid solutions from the first principles. The cluster variation method [1) and the pseudopotentlal method from the first principles [21 are applied. In the traditional variant of the cluster variation method the energy parameters are assumed to be the binding energies of clusters. It is not easy to conduct the microscopic calculation of these parameters because the clusters, are allocated In the crystal and the binding energies are effective due to the Influence of their crystalline neighbourhood. It has been shown in (3) that the special transformations in terms of the cluster variation method enable us to reduce, the expression for the solid solution free energy to the form : TS , j = i ' J where J defines the number of the new energy parameters required for the calculations. They are represented now as binding energies E. of totally ordered structures (TOS). T Is the temperature, S denotes an entropy and y, represents a number of weight factors associated with the cluster probabilities a. by the next relations a .s -jj/j'i. ' here jjj is the fraction of i-th clusters configuration among all the clusters of s type In J-th TOS. The new energetic parameters represent the binding energies of the whole crystal, so they have the clear physical meaning and enable us to perform correctly the calculations. It has been shown that the number of the energy para meters required for evaluation is reduced in the approach proposed. We have developed the choice scheme of the TOS of the kind (independent) among all the possible TOS considering the definite radius of the effective Interaction between the atoms In the solution. Therewith the independent TOS consist of the linearly independent cluster sets determined by the same effective Inter action radius. The primitive lattices, the lattices with basis as well as the lattices with division into the sublattlces are considered. In this case we mean also the plane rectangular lattice, the plane square lattice with division into 1, 2 and 3 sublattices (for example, it Is observed in the superconductor of YBa.Cu.O- ) as well as the bee, fee and hep ones. We should consider also the binary solid solutions of alkaline metals Li, №. К and Rb as an example. Their TOS energies are calculated In the variant proposed of the pseudopotentlal method from the first principles using the true wave functions of the conductivity electrons to calculate the screening effects. It enables us not to consider the concepts of effective valency and orthogonaTization hole (it Is very difficult to estimate the 205 distribution of its charge density), as well as to calculate the energy shifts of core electrons through interaction with non-homo geneous part of conductivity electron density distribution : Л Шт " ~£ ^m<4>W4>ESm^q>vIin(4*>. ™ q m 0» is the average atomic volume, S (q) is the partial structure p . (q) denotes the Fourier-component of nl-th electron charge density distribution in ion of m type, n and 1 are the quantum numbers of the occupied electron core states, v, Li-Na Na<- K K-Rb TOS E B E E B J J J Bj J J - theor. -0.51797.*, 1.36 -0.461528 0.83 -0.393911 0.42 exper. -0.517 1.37 -0.461 0.78 -0.394 0.37 A B -0.496248 1.35 -0.431522 -0.387713 0.42 3 1 0.82 A2B2<1) -0.481751 1.26 -0.414875 0.73 -0.383698. 0.42 A2B2(2) -0.481739 1.26 -0.412487 0.71 -0.383501 0.42 A1B3 -0.470514 1.07 -0.401468 0.57 -0.381250 0.41 В -0.461528 0.83 -0.393911 0.42 -0.379727 0.41 * ..„.• „, , 0 .* unit of measurement E, r By, Bt 10 N/m Thus, the results obtained agree well with tie experimental data.The proposed calculation scheme of the thermodynamic properties of mult(component disordered solid solutions can be applied to the disordered solid solutions with both interparticle interaction and crystalline lattice of any type. REFERENCES 1) N.S.Oolosov. Izv. VUZov, Ffzlka. 8 (1976) 64. 2) Y.Harrison. Pseudopotentlal1 v teorli metallov. M. :Mir.1968.268s. 3) W.A.Krashanintr. Izv. AN SSSR, Metalli. 6 (1988) 61. 2 206 THERMODYNAMICS OF ATOMIC ORDERING IN NONSTOICHIOM£TRIC COMPUUNDS A.I.Gueev, A.A.Rempel Institute of Chemistry, Ural Division of the USSR Academy of Sciences, Sverdlovsk 620219, USSR The atomic ordering in nonstoichiometric Interstitial compo unds MXy (such as transition metal carbides, nitridee and oxides) is widespread. In these compounds atomic ordering is the result of a redistribution of interstitial atoms and structural vacancies in the nonmetallic sublattice sites. An order parameter functional (OPF) method [l,2] is proposed which permits description of thermodynamics of structural order- disorder phase transitions and calculation of equilibrium phase diagrams of a M - X systems. In the OPF method the crystal is described as a set of a clusters with a probabilities P^s) and energies e'f' . The probabi lities of all clusters are represented in terms or a distribution function n(r) that immediately related to the long-range order parameters ty ; the cluster energies are represented in terms of the coefficients of a polynomial that approximates the concentra tion dependence of the formation enthalpy of a disordered crystal. In the OPF method the free energy of a compound HDL. with any degree of ordering has the following form {SJ * *kBTE'En, CALORIC COEFFICIENTS IN MODEL OF FfRITLIBRlLiM ГПИРГГР BY ACTION DF TWO PROCESSES OF DIFFERENT FMY5TCAI. NATURE E.F. Vaynsteyn Institute of Chemical Physics of USSR Ac The caloric coefficients THE THEORY OF THE ASSOCIATED LIQUID WITH COMPLEXES OF DIFFERENT FORM AND SIZE K.Yu .Shiinynev, N.A.Vatolin Institute of Metal ltirge, Academy of Science of USSR,Ural Department.Amundsena st.101,620219,GSP-812.Sverdlovsk,USSR The model of Ideal associated solution is widely used to describe the eonsentration dependences of the liquid alloy thermodynamic propertl.es. In this case the general theory Is developed if to assume the associates of different stolchlometry and size (and self-associates also) to present in the alloy. At the certain calculations we should consider only the single atoms and one (or two) associates of minimum size. It Is responsible for the necessity to decrease the number of the unknown theory parameters, (because every associate has its own equilibrium constant). The decreasing the number of the theory parameters should be realised In the other way, I.e. the evaluation of the associate formation enthalpy (or energy) In the model ' of nearest neihbotir pair approximation. This work is aimed at observing the works [1-71 devoted to the study of Influence of complex size and form on the thermodynamic properties of associated liquid. We have considered In [1-31 that it Is possible to take Into account the associates of different size on alloy without Increasing the number of entrgy model parameters. We realized that these parameters can be evaluated considering the melting temperatures of the different substances. In this case the associates of infinite size is considered as the solid state. The model derived allows therewith to calculate the thermodynamic characteristics of both mixing and melting. This model enables us to estimate the configurattonal contribution ln»o the melting entropy for the multIatomlс systems (2] as well as for the stable compounds [1,5]. It Is shown In [4] that apparatus of the associated solution model can be applied to calculate the llquidus line of the simple eutectlcs. REFERENCES П N.C.Tcknchov.C.Yu.Shunysev and A.N.Men, Phys.Chem.Uq. 15 (19861 271 . 2) N.r.TkachPv.C.Yu.Shunyaev,A.N.Men,N.A.Vatolin, Rasplavy 2(1988) Я (in Russ.). 31 C.Yu.Shunyaev,N.C.Tk.ichev,A.N.Men, Rasplsvy 2 (1988) 1Г (in Riiss . ). 4) N.O.Tkachev.c.Yu.Shunyoev,A.N.Men,N.A.Vatolin, Doklady AkademlI Nauk RSSR :<02 (1988) 153 (in Russ.). 5) N.C.Tkaehev, C.Yu.Shunyaev, A.M.Katznelson, A.S.Krylov,A.N.Men, V.I.Kashfn, Journal FlzIcheskoy HlmiI 63 (1989) 1372 (In Russ.). Г.) N.C.Tk.iebev, C.Yu.Shu'nyaPv, A.N.Men, High Temperature - High Pressure 22 ПЯ90) 207 7) K.Yu.Shunyaev, V.A.Krashaninln, A.N.Men, Ezvestiya AkademlI Nauk SSSR, Metally. In piess. Mn Russ.). 209 THE PHASE TRANSITION PARAMETERS LOCALIZATION BY ELECTROMAGNETIC FIELD A.S.Galperin, G.G. Kuleshov Dept. of Physics, Byelorussian Institute of Technology, Sverdlov Str. 13a, 220630 Minsk, USSR The electric and magnetic fields essentially affect to the state of the thermodynamic system which has nonzero susceptibili ties to external field». This effect takes place in many systems, particulary in the liquid crystals and their solutions . The kinetic of the phase transition in the external fields is studied not sufficiently. So, it is important to consider the electric and magnetic fields influence on the liquid-gas phase transition parameters. We consider a sample of liquid and vapour in equilibrium at constant pressure with alternating eJectric and magnetic field applied so that the Poynting vector is parallel to the interface between the liquid and the vapour, tinder these circum stances the chemical potential of each phase is a function of temperature, pressure and electric or magnetic susceptibilities. The analysis shows that the additional war к of the polarization and magnetization at the phase transition may be expressed through relative dielectric and magnetic permittivities and densities of each phase. This work also.depends an the eleccric and magnetic fields that attenuate to different degree for each phase in the direction of wave propagation. The consideration of the heat capa city change due to the polarisation and magnetization leads to the expression depending on the electric and magnetic fields, dielec tric and magnetic properties and their temperature dependences. The shift дТСг) in the valid transition temperature at the constant pressure as a function of a distance z i: the direction of the electromagnetic wave propagation can be evaluated by using simple thermodynamic considerations. Comparing usual equation for the vapour - liquid equilibrium with that for system perturbed by external alternating electric and magnetic fields at the same pressure we obtain the ccrrelation between phase transition temp eratures determined taking into account field perturbation T or not considering it T, '. TW-T(»-T,» /*"W . A AH/Tg + Cpf-uC,,^) where &Yeam - the additional work of the polarization or mag netization at the phase transition, iH - the latent heat of the phase transition, T0 - the temperature of phase transition in absence of external fields, Cp - the heat capacity at constant pressure, лСвв. .- the heat capacity change due to the polarization or iregno- °HH' tization. It has been shown that the magnitude of phase transition temperature distortion depends on such competing factors as the latent heat of transition, the amplitude of electric and magnetic fields and the heat capacity change expressed through pernu-ttivl- tles as functions of temperature and frequency. At the constant electric and magnetic fields our corraia- tions lead to well known Helfrich equation for the /list order transition temperature shift in liquid crystals;. 210 MARS SYSTEM IS A STAGE ON THE WAY TO THE EXPERT SYSTEMS IN THE CHEMICAL THERMODYNAMICS Bogomolniv A. M. Giprokauchuk, ul. Ibragimova, 15, 105318, Moscow, USSR. The specialists who provide the users with reliable information on physical and chemical properties of the materials perform the following works: -find numerical values of the material properties in literature; -analyse the collected data, select the recommended values which are characterized by high reliability; -search for the properties calculation methods in literature to predict data which are not available in literature; -analyse the collected methods and based on the fields of their application as well as on the data available, select more reliable method and carry out the calculations according to it (or perform calculations according to all methods accessible and after that select more reliable values); -joint literature and calculation data, if required; -present the obtained results in the required form (in the form of a table, graphic or analytical form) and size. The analysis of these works showed that all of them (although to different extent) may be automated. This served to be a base to begin MARS system to establish at Giprokauchuk which modulate, to significant extent, the abovementioned works of the specialists. Data bank is created within this system which contains the values of the whole complex of physical and chemical propeties of more than 2500 organic compounds and their mixtures which are more frequently applied in different fields of chemical technology. One of its features is that the automated analysis of data as well as the choice of the recommended values are performed in it The check of this choice showed that approximately in 90% of cases the difference in the recommended data selected by the specialists and by the system is within the experiment error. Also a library of the calculation methods of a number of physical and chemical constants (melting point and normal boiling point, critical parameteres) is created which allows to calculate the preset property by all the methods accessible for each material based on the data available for it. An automated method to choose the recommended calculation values is being specified nowdays. Then a library of methods to calculate properties depending on temperature as well as a proper method to choose the recommended calculation table are to be established. In future, as the experience in the automated choise of literature and calculation data is accumulated, the creation of the base of knowledge and expert system in the fielu of chemical thermodynamics will be quite real. MARS system is a.step in this direction. We offer cooperation to Soviet and fore in organizations interested in joint using, extending and distributing data bank MARS in the Soviet Union and abroad. -?II DATA ВАЗЕ ON INTERPHASE COEFFICIENT OF MICROIMPURITY DISTRIBUTION IN HIGH-PURITY SUBSTANCES. A. R. Fldelman, V. M. Stepanov Institute of Chemistry of High-Purity Substances, USSR Academy of Sciences, 49, Tropinin St. , N.Novgorod, 603600,USSR An automated data base (DB) on the coefficients of К microimpurity distribution at the phase equilibria of liqui.d-vapour and crystal-liquid systems has been developed at the Institute [13. DB is realized on a personal computer. The experimental part of DB on phase eqiulibrium of crystal-liquid system contains more than 700 values and on phase equilibrium of liquid-vapour system - about 300 values (mainly the systems formed by elementary substances, inorganic halogemdes). The extension of the available data is possible only in case the methods of К calculation are applied taking into consideration the properties of individual components. The DB has the calculation part containing a number of methods to calculate К for both phase equilibria. The calculation part of DB makes it possible to calculate temperature dependencies of К for liquid-vapour phase equilibrium. Ideal solutions approach as well as approaches, based on different models of condensing phases structure, are used. Formulae based on ideal solutions approach are of estimating character, but it is enough to know only impurity component melting heat value and both components melting temperature values (in the crystal-liquid phase equilibrium case) or both components vapour pressure values (in the liquid-vapour phase equilibrium case). Methods to calculate K, based on models of condensing phase structure provides more exact results , but it is necessary to know density values, evaporation heat values, geometrical form of molecules and some other values for both components. At the present time the DB contains the data on properties of a wide range of individual substances (inorganic nalogenides, hydrides). The possibility to edit and extend the data is provaided. The DB allows to collect and systematize the data on К for a large number of systems. The availability of statistically representative data bulk makes it possible to consider generalized problems to predict the efficiency of respectiv single stages of purification as well as to verify the data on K. The processing part of DB contains the facilities to solve the above-mentioned problems on the basis of apriori data on the type of distribution function of logarithm К values in various bases of the systems CZ1. Distribution functions of logarithm К values are of trapezium type for the most important cases in practice [31. REFERENCES 1. A. R. Fidelman, V. M. Stepanov /Vysokochistye veshchestva. 1990, N 6, p. 76. 2. V. M. Stepanov, A. R. Fidelman/Vysokochistye veshchestva, 1988, N 1, p. 32. 3. G. 6. Devyatykh, V. M. Stepanov, S. V. Yan'kov /Vysokochistye veshchestva, 1988, N 2, p. 5. 212 ОКБ USING ОТ THE DATA ON DISTRIBUTION COEFFICIENTS TO OBTAIN THE THERMODYNAMIC MODELS OF THE PHASE DIAGRAMS OF BINARY ALKALI HALIDE SYSTEMS. V.I.Kosyakov,V.M.Paasonen, v.A.Shestakov.G.E.Osipova. Institute of inorganic Chemistry, Siberian Branch of Academy of Science, Novosibirsk, 630090, USSR The literature data on the thermodynamic properties of pha ses and phase diagrams were used to produse the thermodynamic models of 10 binary systems Involving the alkali halides with a common ion» The same problem was handled in (1). In comparison with this work we additional? used the data an equilibrium dist ribution coefficients to overcome the information defioite about solidus. The distribution coefficients data were taken from the lite rature or were measured by the normal freezing method. The slow crystallisation rate and Intensive miring of the melt were used to realise quasiequllibrium regime. The polinomial model was used to describe excess Qibbe enrgl^ of solutions. The coefficients of the model were obtained under the method (2,3), The table contains the two system model coefficients* lor the second system it was accepted that Gibbe energies of stable and metastable phases of Csl (types CsCl and FaCl) were equal. Function KBr-NaBr CsI-KI bid Liquid Ъ -2121.26 11 1 -*96,603 Т -0.2122*3 0 ъ12 Ъ21 X 201.8*4 0 XT 2.0782* 0 ь22 Solid et £ 1 14137.2 3732C.9 11703.0 ь11 Ъ -28.0669 9.562*2 12 Т -6.7880* Ъ 0 21 X 1555.62 7772.31 0 -*5.6388 ъ22 хт 1.81179 2 Ъ х 0 0 5833.75 31 2 Ъ32 х ! 0 0 16.5005 1 -1 Дех Н f J mol -200 \ / -400 ' V / -600 *"*^ (_,_ I I I I i__i_JX 0,5 1,0 1 Дт>Л , J mol" 0 ^^*^"**л -1000 -2000 _ i.—1_ iiii t Л x 0,5 1,0 4exHs, J mol" 4000 3000 • 2000 1000 0 0,5 1,0 0 0,5 1,0 Phase diagram, distribution coefficients and thermodynamic properties of phases for system КВг-NaBr. The lines were counted in according with mihdels in the table, points con form to experimental data. EEFKRENCES 1. J.Sangster, A.D.Pelton. J.Phys.Hef. Date 16 (1987) 509. 2. H.L.Lukas, E.Th.Henig, B.Zimmerman. Calpbad. 1 (1977) 225. 3. I.A.Mergano-v. J.Phys. Chem. (Hus.) 59 0985) 870. 214 PADE APPROXIMATION OF THERMODYNAMIC PROPERTIES OF SOLID METALS FROM О К UP TO MELTING POINTS. L.R.F.kin, V.YA.Checkovskoi Institute for High Temperatures, Academy of Science,5, Moscow 127412, USSR At present time the possibility of calculation of thermodynamic properties Cp(T) and ^e y^OT-of solid metals from first prin ciples on the basis of pseudopotentials from О К to melting points (Trap) within the limits of errors of modern experiment ( ЪСр < 14, f J 6 0 a, T +...+aT В 2 В X(T,a,b) = a T + + kR( ) EXP< ) (1) 1 1 + Ьi T • ...+ bi T6 R*T R*T X * with nuclei of Pade-approxlmanta, where 1=1 for Cp and 1=0 for X. The expression (1) has a true asymptotlcs for electron and lattice component when T-»0 and for vacancy component when T-»Tmp. Parameters a, b of equation (1) are defined by means of nonlinear least sgures method with joint treatment of the experimental data of Cp and enthalpy H,.- H for Cp(T,a,b) and Jj and thermal exp- panslon Д1/1 for Л/(Т,а,Ь)Mt . The results of approximation by the equation (1) are the following : 1) Debye function Cv(T/8), 0 2) Cp, Нт- Нмй for tungsten, О К - Tmp /2/; 3) Cp for mercury, О К - Tmp /2/; 4) Cp, H - Hg^t for molybdenum, О К - Trap /3/; 5) «0 r bl/L for molybdenum, О К - Tmp /3/. REFERENCES : 1) L.Fokin, G.Puchkova, "YI All-Union conf. on calorlmetry." Tbiblci Metsnereba (1973) 359. 2) G.Puchkova, L.Fokin, V.Checkovskoy, Quartime conf. int. de the- rmodynamique. Montpelller. France. 11/19 (1975) 60. 3) Thermophyslcal properties of molybdenum and its alloys. Moscow: Metallurgies (1990) 302 p. 215 PREDICTION OF ЩЕКОТКИ bVU PSSUDOSTSTEMS OF TKRMAfiY SYSTEM A.N.Mamedov, A.S.Abbasov, I.G.Metehdiev Institute of Inorganic and Physical Chemistry, Institute of Physics, Academy of Sciences, Azerbaijan SSR, Baku, USSfl For calculation and approximation of phase diagrams and thermodynamic functions of ternary systems with complex interac tion of components one should divide them into symplexes -pseu do binary and pseudoternary subsystems.In transition from one standard state to another t»e model concentrations and parameters of prepared solutions of non-molecular compounds are recalcula ted. For simplification of this problem and programming of the calculation on EC we have received and approbated on concrete systoms the formulas for components of ternary and pseudoternary systems the most often met in practice. The connection between component concentration of ternary system ( Zi) and its pseudosystems ( 1" ) is expressed by the formula . , .1 ' Here M and M is a square matrix of the third order and a re verse matrix indicating component concentrations in nodes of ter nary and pseudoternary system /l/.For example,for pseudoternary system AAW-bpCjO- ЛпЬвГ,гсл) in ternary system AW-BW-CW (D-(i)- (IH(1) /pc-qb qa -pa M= [ft p Ь J; M = v f ' \ Щ -Щ Щ Tor transformation of tnermodynamic equations for predicti on of eutectics of ternary systems applicable to pseudosystems the functions f(X) were used with respect to the model of li quid and solid solutions of non-molecular compounds /2/.For exa mple, for pseudoternary system Here: Nfcfo-I^m+^+XstP'Ctf + IeCtt-D'C); J^-molHact. of compound components .in tne pseudosystem 4—5-o Calculation methods based on application of the function above are successfully approbated for prediction of eutectics of ternary systems forming dual,ternary compounds and with, occurren ce of division into layex-s in the liquid phase REFERENCES 1) A.Mamedov et al., Azex-b.Chom.O. 1 (1939) 2) A.Mamedov, Synopsis ox' Thesis for Doctor's .Decree,Tbilisi (1939) 216 ASSOCIATIVE MODELS IN THERMODYNAMICS OP SOLUTIONS AND IN RELATED REGIONS. V.A. Durov Department of Chemistry, Moscow State University, Moscow, W-234, 119899, USSR. A review is given of the etate and problems of molecular theo ry of associated liquid systems. The main attention is brought to the consideration of associative models and their applications in thermodynamics as well as in dielectrometry, theory of Rayleigh Boattering of the light and relaxation spectroscopy of liquids and solutions. New models of non-ideal solutions (mixtures of associates) of the arbitrary composition, methods of calculation of contributions of universal and specific molecular interactions to thermodynamic functions of liquids and solutions are worked out. The repulsive interactions of molecules are desoribed within the statistioB of athermal mixtures and they are characterized by the geometrical (dimension, form) parameters of molecules, the universal interac tions are calculated in continual approximation and they are expressed in terms of eleotrooptical parameters of medium (static permittivity, refraction index) and molecules (dipole moment, polarizability etc), the contributions of speoific moleoular inte ractions expressed in terms of thermodynamic characteristics of associative equilibria and structural parameters of associates.For the first time associates of arbitrary composition as well as the possibility of formation the intermoleoular bonds in associates by various ways are considered in developed models. The structural multiformity of associates within one topological olass (linear, oyolio etc) is established and the methods for description struc tural features, electric and optioal properties of polyvariant as sociative forms are developed. New formulas for ooeffioients of activity of components, excess enthalpy and GibbB energy of solu tions for whole region of concentrations ав well as for thermody namic parameters of solvation and solution at infinite dilution are derived. The contributions, corresponding to mentioned consti tuents of moleoular foroes are oaloulated for some systems; the necessity of exact calculation of dipole contributions to excess functions of solutions are established. The problems of construc tion of the interrelations between thermodynamic funotions of transfer and moleoular parameters of solvents and solutes are discussed. The new interrelations among statio permittivity, ooeffioi ents of integral isotropic» and anisotropic Rayleigh scattering, parameters of relaxational (dielectric, acoustical) spectra of liquids and thermodynamic, structural, kinetio oharaoteristios of associative ргооеввев are established. Applications of the developed common theory in the investiga tions of moleoular nature and calculations of thermodynamic, dielectric, optioal, relaxational properties of some olaeses of associatec*. liquid systems (alcohols, amides, amines, nitriles eto as well as their solutions) are considered. REFERENCES 1) V.Durov, In: Solutions of Noneleotrolytes in Liquids. (USSR). Moscow, 1989, 36-102. 217 HIGH RESOLUTION THERMAL ANALYSIS AND CALORIMETRY: IMPROVED TOOLS IN MARTENS IT IC TRANSFORMATION STUDIES СSHAPE-MEMORY ALLOYS) H. Tachoire, V. Torra (>) Lahoretolre de Thermochiale, Universlte.de Provence F-13331 Marseille CEDEX 03 («) Applied Physics Dept., ETSCCiP, Univ. Pol. Catalonia E-08034 Barcelona Most applications of shape-memory alloys rely on a precise knowledge of the hysteresis cycle of the.alloy. In fact, the actions of the various thermomechanlcal treatments and of the time are still not well determined. This situation is due to the peculiarities of transformation that takes place between metastable phases. In the present state of the art <1>. Mainly research towards strict control of the Baterial and towards the availability of reliable and reproducible knowledge about the state variables stress - strain teaperature. Only correct reproducibility during a large number of work cycles permits effective devising of the preparation of substitution elements, for exaaple in newly-developed technologies such as is required in robotics. More relevant to us is the fact that the hysteresis cycle of a given alloy may depend on previous theraomechanical treatments and, as a consequence, the properties may be substantially altered after repeated cycling through the tranforaation region. There are a number of factors that determine the hysteresis cycle of an alloy <2>. Among then, we find the concentration of defects (vacancies, dislocations, ...), the state of the atomic order of the alloy (3) and the existence of other.phases (precipitates). Their effect on the kinetics of the transformation and on the hysteresis cycle may be different after a sequence of forward and reverse trensformatlons or cycles. It is in fact well known that, in some cases, repeated, cycling may lead to a loss of double memory effect. Recent experimental work has shown that the temperature resolution which is needed in order to isolate and characterize the elene.ntary events is of order of 0.01 K, one order of magnitude higher than the resolution of devices which are being used to investigate the properties of aartensitlc transformations. In this work, we describe 1) the experimental set-up (4) and signal processing (5-6) for high resolution thermal analysis (see figure) and derived/adapted Instrumentation (thermoaicroscpy, thermosoninetry, unconventional DSC, testing machine) (7) 2) experimental measurements; see, for instance, studies performed in ' the hysteretic behaviour (global or local transformations) In the former case, by using an unconventional «canning calorimeter suited for solid ' state transitions studies. In the later, local studies were performed by means of AE detection, resistance measurements, optical microscopy observation and/or stress - strain - teaperature aeasureaents of the samples. For this purpose, partial cycling In accurately controlled conditions was performed on samples of Cu-Zn-AI alloy, in which the growth shrinkage of single aartensite plates could be observed (8). The hyste retic behaviour gives information about the frictional resistance of the interface motion (or, in thermodynamic sense, the entropy production), elastic energy stored/released, pinning mechanisms, coexistence of several eartenslte phases, nucleatlon processes, tiae scales, ... Observations in the "alcroscale" domain or local growing / shrinking (8-11) shows: 1) acoustic emission (AE) bursts are closely related to the pinning effects, also, AE Is a sensltltlve tool in order to detect changes In the material; 2) accurately controlled ?.1б temperatures end temperature rates are necessary to obtain strictly recoverable state?; 3) intrinsic theraoelasticlty relied at the Interactions between Interphase and dislocations by the growing / shrinking of the stacking faults; 4) Irreversible Interactions (destructive Interactions) between interphase and у precipitates. Left: Experimental set-up for thermomicrascopy, acoustic emission, unconventional DSC and others'; A) Brass block immersed In a thermal bath; B) Peltier thermobatterle; C) working space at temperature regulated; D у E> caloriaetric thermobatterles (Seebeck effect); F> resistance Pt-iOO; G> electrical links Rlgth: Block diagram; A) Experimental set-up; B) resistance measurement R(t) by DHM HP3478A; C) thermogram s(t) by DHH НРЭ478А; D> Peltier effect lit) by DHM HP3478A; E) Power supply (Premium SR - 120); F) 6PIB board; G) switching board; H) digital/analogic converter (board: ADDA 14); I) PC-XT computer REFERENCES 1) Science and Technology In Shape - Memory Alloys, Proc. COHETT Course, V. Torra Ed., Univ. de les Hies Balears (1989) (Spain) 2) H. Tacholre, V. Torra, Can. J. of Chem.,67 (1989) 983-990 3> A. Planes, J. Vinals, V. Torra, Phil. Mag..Л 48 (4) (1983) SOI 4) A. Amengual, V. Torra, J. of Phys. E: Scl. Instrum., 22 (1989) 433 5) H. Tachoire, J.L. Macqueron, V. Torra; NATO ASI Series С 119, (1984) 77-126, D. Reidel Publishing Co., Dordrecht 6) Thermokinetics. Signal processing In Calorlmetrlc System, W. Zlelenkiewlcz Ed. Ossollneum Warsaw 1990 7) A. Amengual, V. Torra, A. Isalgue, F. Marco, Theraochlm. Acta,lSS (1989) 115-134 в) С Plcornell, C. Segul, V. Torra, F.C. Lovey, R. Rapactoli, Theraochim. Acta,113 (1987) 171-163 9) F.C. Lovey, J. Ortln, V. Torra, Phys. Lett., A 121 (7) (1987) 353 10) A. Amengual, F. Garcias, F. Marco, C. Segul, V. Torra, Acta •etall.,36 (8) (1988) 2329:2334 11) F.C. Lovey, A. Amenguai, V. Torra, M. Ahlers, Phil. Mag., A 61 (1) (1989) 1S9-16S Financial supports from Provence University, CICYT project НАТ-ПАТВ9 - 0407 - COS and EURAM 0803/3 MA1E - 0010 - С (GDF) are gratefully acknowledged. 219 THERMOKXN.ETICS - APPLICATIONS,LIMITS U. Zielenkiewicz and E. liar gas Institute of Physical Chemistry of Polish Academy of Sciences Kasprzaka 44/52,01-224 Warsaw,Poland An important domain of the application of calorimetric sys tems is the determination of thermokinetics WCtt.This function is used to establish the kinetics parameters of different chemical reactions lit can be used to examine the metabolism of living sys tems; the growth of bacteria and plants ; for studies of changes in human blood. General new methods were elaborated recently for the reconst ruction of thermokinetics H(t) [1,23. The increasing availability of on-line or off-line dedicated computers makes calculations at W(t) for each measurement easy. Application of modern methods of reconstruction at thermoki- netics is justified only if certain conditions are fulfilled. The authors consider that the major importance have the following of them : 1) equivalence от the heat sources during calibration and measurement | 2) the choice of proper sampling period for the given preci sian at measurement ; 3) the choice of the correct method of determination of the dynamic parameters of the calorimeter or at least the transmittan- cel 4) the correct choice of the measurement methodology accor ding to the criteria of kinetics limits. REFERENCES 1. Thermokinetics .Signal processing in Calorimetric System,Ed.- M.Zielenkiewicz,Ossolineum,Wroclaw 1990. 2. W.Zielenkiewicz and e.Margas,Podstavy teoretyczne kalnrimetrii dynamiC2nej,Ossolineuni, Wroclaw 1990. 220 AN AUTOMATED SYSTEM FOR CAI/ORBtETRIO MEASUREMENTS V.V.Repkov, N.I. Matskevich, G.E.Oeipova Institute of Inorganic Chemistry, Siberian Branch of the Academy of Sciences of the USSR, Novosibirsk 630090, USSR Л device is described created in the CAMAC standard inten ded to interfaee.the calorimeter heater and thermal detector to an "Electronika - 60" computer. The device has been employed to automate a dissolution calorimeter /1/ to increase the calorimet- rlc measurements accuracy. The main advantages of the system is a high accuracy at a small size (the dimensions of the device are the eize of а СЛМАС board). The module is to an extent multipur pose and can be used as an independent system in different calo rimeters. The module includes (Tig. 1). 1. A source of reference voltage (10 V). Long-time stability 100j*V, short-time stability 10j*V (i.e. 10"5- 10"6). 2. A digital-to-analog converter (DAC) to preset and stabilize the heater voltage. The voltage stability is 5*10 within a day. 3. A $lmer (TM 1) to control the DAC operation. 4. An analog-to-digital converter (ADC) to measure signals from the thermal detector and the heater voltage and current* The ADC resolving power la 10 at an integration time - 1 sec and 10 at 20 sec. 5. A timer (TM 2) to give integration time for ADC. 6. л companion temperature measurement circuit. The unit invol ves an operational amplifier and two resistors RQ and R... The sensitivity of the circuit is 10"' K. The automated calorimeter constructed using the above modu» . le has a reproducibility of 0.03% (relative to 0.1$ for non-auto mated apparatus). The programme provided an automated recording on the dlscettes and reading from the dlsoettee of the temperatu re arrays. Correctness of the calorimetrio system has been chee ked from the heat of dissolution of potassium chloride ( AP H = 17.529 i 0.009 kj/mol). REFERENCES 1) Pepkov V.V., Matskevich N.I.,0aipova G.E., Erofee. R(iherma€ detector) 222 MI CROCALORI METRIC STUDY OF THE ENERGY DISSIPASION PROSESSES IN FLOWING DISPERSE SYSTEMS S. V. Pachovchishin, A P. Shimanski j Surface Chemistry Institute, Ukrainian Academy of Sciences, Nauki aw. 31, Kiev 028, 852028, U. S. S. R. and V.V.Mank. N.I.Lebovka, Natural Disperse Systems Department, Physico-Qhemtcal Insti tute, Ukrainian Academy of Sciences, Vernadsky av. 42, Kiev 142, 252142 U. S. S. R. The processes of energy dissipation in the water and silicone dispersions of silica, methylsillca and alumina under the shear stresses are studied by the calorimetry method on the "Tyans -Kalve" type calorimeter. The special Hoppler-type vtscostmeter cell for submerging into the calorimeter was constructed. The shear stress was changed within the interval у - 0,2-50 cm" . The sourses of the thermal effects being measured in the experiments are analysed. Also the invesllgatlon of the rheologlcal properties of the dispersions mentioned above in the rotational vlscoslmeter are made within the wide range of r and the solid phase volume fraction. The thermal effects dependence on the solid phase concentration, type of surface and of dispersion media Is studied. The energy being dissipated versus the shear rate dependence is investigated for the pure liquids as well as for dispersions made in them. The heat evolution is shown to increase linearly with the dispersion viscosity at high shear rate values. The energy dissipation, structure breaking and relaxation processes in flowing dispersed systems are discussed. ггз L N. Galperin, A. S. Wejsnov, J. R. Kolesov, V. V. Stelushpsnov Departamant of Institute of Chemikal Physic, Akad.SCI, Chernogolovka, USSR. FAST METHOD OF HEAT MEASURES. Previously developped [11 ballistic method of impuls heat mea suring (burning,dissolving and so on) has inkluded process of pre liminary heating of calorimeter bomb, measuring of ballistic def lection (Um),interval of time to maximum deflection (tm) and calcu lation of heatrQ = k(Um + totm/r ),where к,Цо,Г-аге constants. A new method [23 has been developped which don't require the preliminary heating and calculation of Uotjr/c so the process of measuring is simplified,the productivity is increased and the pre cision is improved. Ideas of this method are based on creation of the electric equivalent of calorimetric cell ( CC ) and on inclu ding it in measure circuit what permitted to compensate the loss of heat during the time (tm) without taking into account heat state of CC (the temperature of CC being higher or lower than that of calo rimeter) at the moment of initialisation of burning. Automatic bomb colorimeter (Fig. 1),based on this method (with CC to be analogous to ГЗ] has the following parameters: accuracy - 0,1% at range of heats Q=80-10000 J and time of с measuring 8 - 10 mm. £>f7=s£> Y-Piior CALORIMETER fi.C. A№iF№ _ RC=Zcc ьь. SAMpLCCC JWFfREITCECC T I EQu'lVAiEHl 1 I OF CC Fi&.l 1. L. N. Galperin, A. S. Neganov, J. R. Kolesov, A. Cer USSR #229605 05. 86. 12 conference of calorimstry,Sor'ky,1988,P. 230 2. L. N. Galperin, A. S. Neganov, У. V. Syslus^amvЛ&-ЖШ//£2//0/г^^5. 224 PRECISION GAS CALORIMETER A.A.Vlchutinsky Frumkin Institute of Electrochemistry, USER Academy of Sciences. 117071 Moscow, USSR. For research and experiments aimed to prove the universal principle of non-equivalence of work and heat the author of the theory has developed and is now finishing the construction of a original calorimeter for measuring the heat of gas volume change. The calorimeter range of operation is -50 - +50 C, at pressure of up to 25 atm. A copper detector unit is essentially a cylinder with two covers, 100 kJ/K heat capacity. The metering cell (volume - 11 1) is made of 0.45-mm sheet copper. The heat detector is composed of semiconductor microooolers (27? pes). The detector parameters are as follows: integral sensitivity apr.0.17 V/W, sensitivity 2.2 V/K, electric resistance 400 ohms. A plati num (0.05 mm)resistance thermometer for 100 ohms is designed, for gas temperature measurements. A piston proportioner, for ohanging gas volume (± 100 ml) is provided with a heatlinearizing device used as a suspension for placing the detector unit in a thermos tat. The heattransfer agent is fed a copper flask (ф530хЮ50 mm), containing a high-pressure vessel ( with the deteotor unit sus pended in it on the proportioner cylinder) suspended in the outer high-pressure vessel (0630x1250). The heat-transfer agent flows from the copper flask along 12 channels over the internal surface of the outer vessel (with 250-mm thick crumbled foam-plastic in sulation). The proportioner actuator is brought out via the glands of the flask and vessel covers. The proportioner is hand- actuated (within 0.2 s), the stating moment and shifting period are recorded; the shifting range is fixed with a set of gauge blocks (1 - 250 mm), class 2 (J,m. Slow linear actuation of the proportioner is effected with a micrometer screw (length 200 mm), from a oathetometer with а ЩЦ-4М stepper motor. For low rates of volume change an external proportioner is provided, operating from a 0.200 ml/40 rounds micropipet,tt.. Weight of the installa tion is 1 ton. Expected operating precision to 0.02 %. For measuring the gas pressure a mercury barometer precision to 2 urn, with line standard metre (1000 mm), class 1 urn, was designed and manufactured, for reference points 0.5; 1 ± 5 .*; 1.5 and 2 atm. A precision pressure gauge system for up to 12 atm. is being made. At present the installation metrological equipment includ es: P3G0? voltage comparator - 3 pes; Ф118 nanovoltmeter - 2 pes; digital voltmeters Б7-34 - 2 pes; B7-43 - 1 pes. Being finished is an automatic data recording, accumulating and processing sys tem. To obtain accuracy of the installation (to 0.001 %) it is necessary to have 2 high-speed digital multimeters "midi", model 7063. with simultaneous computer recording of the thermal and temperature signals. This supreme instrument is the product of Sohlumberger Technologies Instrument division, England. The author plans to demonstrate the operation of the installation (designed to measure the gases heat capacity by volunivtrio-thennal transformation method) to the members of the International Symposium on Calorimetry and Thermodynamics, to.be held In Moscow, June 23 - 28, 19"?1. 225 "ЗИО.;Г" iuiTHOi) О* CiiSjuilC OCiu'OUMS KJRITJf ЛЛМймГНАТЮМ ЗЗГ D3C. H.V. Avromenko and ii.D. ..'opor Dept. of Chemistry, Moscow State University, Moscow, U.3 .a ,R. 2he technique below was developed by means of a differen tial scanning calorimetr DSC-20, Mett.ler. Two methods were com pared: "common"- using Van't Hoff (1) equation for purity deter mination and developed by us "short**- allowing to determine the amount of purity in substances, which decompose some time after melting starts (eq. 2-3). * ""ига—r2"—L-ч— (2) 0 дН,+ К T_- Э?2 АН,- ДН2 йНз 'Jg- т, " дН1 "иф-щ: к (3) - ДН3-АН2 Т3- Eg Т дН^-лН1 - Т2- 1 х - mole fraction of impurity in the original sample, T -• melting temperature of the pure main component, in K,, Mf - heat of fusion of the pure main component in Jmol , F - fraotion of sample melted at Tf, R - gas constant, 8.314 J- mol~,ldeg, И - molecular mass of the main component, m - sample mass in mg, К - correction for linearization in mJ, 1 дН1 „ j- partial heats of fusion at Tj, Tg, T_ in J-mol . It is clear from the equations (2,3) that to know ftH. of' melting (required by eq.ljr for purity determination is not neces sary instead one can use part of the melting curve. The comparison of methods on standard samples like: indium, gallium, dimethylterrphtalate, phenolphtelelne, bensoic asid showed good agreement with the results. It became .possible to apply a "shorfmethod for purity determination of newly syntte- sised organic semiconductors such as: bis(ethylenedithio)tetra- thiafulvalene, tetrathlotetracene, bis(cyclopentenedithio)tetra- thlafulvalene. 226 TAtU A0IABATIC CALORIMETER: FEATURES ADD METROLOGICAL RESULTS. V.G.Gorbunova.V.A.Medvedev, N.P.Rybkln and E.L.Sorkin National Scientific Research Institute for Physico-Technical and Radiotechnical Measurements,141570 Hendeleevo. Moscow region. USSR. Precise measurements of specific heat give very valuable thermodynamic*! information. But these measurements are the painstaking ones especially when done in the liquid helium temperature range. Here we describe fully automated adiabatic calorimeter developed in our laboratory . which is now produced commercially by our institute. The main principles of its construction were published lately /1/. The calorimeter consists of the KTl mini insert cryostat and the AKSAMIT computer measuring system /2/. We use well known adiabatic technique, and the software allows both step and scanning modes of operation. The temperature of the calorimeter is measured by the TSRGH-2 rhodium-iron resistance thermometer which is calibrated on the 1TS-90 scale. The resolution is better than 1 mK and the absolute temperature error is not worse than 5 mK in the entire range of temperatures from 5 to 350 K. The calorimetrlc cell has two modifications, the first one being fitted only for bulk specimens and the second for liquids, powders and bulk specimens. The latter has the stainless steel container with approx. Ice volume. The lid of this container is sealed with indium ring. The cryostat has the total mass less than 1.5 kg and it can be inserted into commercial STG40 or STG25 helium transport vessels. There is no constant pumping since high vacuum is provided by charcoal getter. The vacuum jacket is sealed with the KPT8 paste which simplifies the routine of specimen changing. The AKSAMIT computer measuring system performs all the operations of temperature and heat measurement, adiabatic control and data processing. There is a possibility of statystical analysis of the obtained results, too. Metrological features of TAU1 calorimeter were studied in the set of measurements of reference copper specimens. Two of these specimens were made of OSCH11-4 high purity copper, and seven were made of MOB oxygen free copper. Both high purity specimens and the MOB ones were from the batches measured on National Specific Heat Standard GET79-75. The main error of measurement decreases from 1.2* at the lower temperature limit to 0.4% at 40 К and higher. We found a small but sharp specific heat anomaly near 13.8 К in all the samples made from oxygen free copper. The peak was 3% high and 0.S К wide. It had disappeared entirely after annealing of the samples at 1000 К in the vacuum furnace was made. We ascribe this peculiar fact to the small amount of hydrogen initially dissolved in the oxygen free copper. It turned out that 40 litres of liquid helium were enough to measure seven or even more samples from 5 to 110 K. We use liquid nitrogen bath for higher temperatures as usual, but 300 К may be obtained in helium bath if necessary. 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И4 Hllpert K. 22 Kolker A.M. 154 Holodov I.A. 66 Komarek K.L. 19 Komissarova L.V. 73 Igumenov I.K. 113 Konings R.J.M. 27 llyinych N.I. 38 Kopecky K. 26 Isaeva E.5. 139 Kopnushev S.B. 104 Ivanov G.G. 80 Korobov M.V. 79 Ivanova E.F. 146 Korolev A.M. 100 Ivanovsky L.E. 202 Kosinova n.M. 73 Izatt R.M. 119,120 Kostyanovsky R.G. 115 • Kosyakov V.I. 212 Kabo G.J. 96,97,105 Kotovich K.Z. 112 Kachurina N.S. 112 Kozyro A.A. 96,97 230 Kozhlna E.L. 77 Lutsareva N.S. . 52 Kozina M.P. 114 Lukyanova V.A. 114 Krashaninin V.A. 204 Lyubarsky M.V. 108 Krasnov K.S. 72 Krasulin A.P. 97 Mamedov A.N. 219 Krechetova G.A. 75 Manero M.H. 94 Krestov Al.G. 154 Mank V.V. 142,222 Krestov G.A. .155,157,164 Margas E. 219 Kruk V.S. 96 Marinin D.V. 172 Kudin L.S. 72,83 Markov V.N. 157 Kulagina T.G. 60 MArsh K.n. 190 Kuleshov G.G. 209 Mathews C.K. 23 Kulikov M.V. 154 MAtskevich N.I. 44,220 Kulikov O.V. 153 Matvienko V.G. 87 Kun Li 54 Mavrin A.A. 79 Kurochkin V.K. 115 Mc Ginnis T.'P. 121 Medovschikova L.A. 107 Lakshmi Naraslmpan T. 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V. 155,156 Litvinenko V.A. 70 Myers C.E. 26,30 Luk'yanov V.B. 90 Lunevich A.Ya. 162 Narkevich I.I. 182 Lusternik V.E. 66 Nasretdinov A.A. 82,84 231 Naunov V.N. 52,55 Petrenko S.V. 138 Nazmutdinov A.G. 107 Petrunin V.A. 109,131 Neckel A. 26 Pilcher G. 93 Neganov A.S. 223 Pimenova S.M. 114 Nekrasov V.N. 201 Pimerzin A.A. 107,118 Nesterova T.N. 107 Piotrovskaya E.M. 178 Nicolaychuc A.N. 140 Plachotnik V.N. 86 Nlkitin M.I. 73 Pogrebnoy A.M. 72 Nistratov V.P. 62 Poltoratskey G.M. 147 Novikov A.N. 145 Popova O.V. 137 Ogden J.S. 25 Popova T.L. 44 OgorodovaL.P. 49 Poshevneva A.I. 71 O'Hare P.A.G. 17 Priselkkov Yu.A. 89 Onuchak L.A. 188 Prokofiev A.R. 149 Orendacheva A. 68 Ortega F. 9 Quanishbaeyev T.D. 133 Oschepkov D.I. 81 Rand M. 20 Osetsky A.I. 141 Rabinovich I.B. 62 Osipova G.E. 212,220 Raevsky Y.A. 144 Otin S. 123 Rafeev V.A. 100 Ott J.B. 119,120 Raspopin S.P. 74 Reading J.F. 122 Paasonen V.M. 212 Reeddijk J. 173 Pachovchishln S.V. 222 Relkin P. 124 Paksoy H.O. 128 Renpel A.A. 206 Parfenova L.N. 147 Repkov V.V. 220 Pasadakls N. 111 Revelsky I.A. 115 Pasasia B.K. 158 Reznik G.V. 184,186 Pastukhov Yu.G. 175 Rodionov I.V. 46 Paukov I.Ye. 57,58 Roganov G.P. 105 Pavlenlshvili T.A. 41 Rojas L.A. 140 Pavlovsky Yu.P. 111 Rpstovshikova T.N. 139 Pedley J.B. 92 Routie R. 94 Perelygin I.S. 148 Rozen A.M. 134,195 Pervov V.S. 46,199 Rozhnov A.M. 106,149 Pervova Yu.V. 79 Rubtsov Yu.I. 100 232 Rudakova S.V 108 Sisoev S.V. 57 Rusanov A.I. 16,179 Skorlkov V.H. 91 Rycerz L. 34 Skrlpov V.P. 170 Rybkin N.P. 226 Slessarenko O.A. 168 Ryzhov M.Yu. 82,84 Slobodov A. 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A. 224 Vidavskil L.M. 51 Vigdergauz M.S. 187.188 Vismanathan R. 23 Vlaskina 0.1. 57 Voit A.V. 172 Vorob'ev A.F. 130,133 Voronin G.F. 6 Vostrikov D.V. 55 CONTENT Plenary lectures , 3 Invited lectures 8 Poster communications on the following topics: 1.Thermodynamics of inorganic compounds 22 2. Thermodynamics of organic compounds 92 3. Thermodynamics of solutions and multicoaponent system 119 4. Thermodynamics of the surface phenomena ; 165 5. Thermodynamics models and databases 190 6. Experimental techniques and data processing 217 Auther index 227 Сборник статей по термохимии и термодинамике редактор ссстгмитель Л.Т.И. Н.В. Коробов Тираж 250 экэ. Литературно-издательское агермгство Р»' Элинина I090I7, Москва, Ордынский тупик д. б Формат 60x84/8. Тираж 250 экз. Объем 28 п.л. Офсетная печать. Заказ 443 ПИК "Патент", г. Ужгород, ул. Гагарина, 101 specifies the formfactor of the screening potential. The calculated values of the binding energies, the lattice parameters arid the bulk elasticity niodulae .for the alkali metals with bcc lattice agree with the experimental data accurate to some percents. In the Table we show the calculated equilibrium values of binding energies and the TOS lattice parameters for the solid solutions considered. The conducted calculations of the free energy and the mixing free energy of these solid solutions enabled us to build the state diagrams. For the K_Rb, _ we can с 1-е derive the non-restricted solubility at the medium temperatures, and for the other systems we can derive the very restricted solubility.