Indian Journal of Chemistry Vol. 44A, July 200S, pp. 136S-1371

Densities and viscosities of binary liquid systems of with aromatic ketones at 308.15 K

T Savitha lyostna & N Satyanarayana* Department of Chemistry, Kakatiya University, Warangal S06 009, India Email: [email protected] Received 25 November 2004; revised 31 March 2005

The densities and viscosities for the binary mixtures of acetonitrile + aromatic ketones (acetophenone. propiophenone, paramethyl acetophenone and parachloro acetophenone) at 308.1S K over the entire range of composition are reported here. The densities and viscosities have been used to calculate the excess molar volumes and deviations in viscosity. The excess molar volumes and deviations in viscosity are fitted to a Redlich-Kister type equation. Other parameters like excess Gibbs free energy of activation of viscous flow and Grunberg-Nissan interaction constant are also utilized in the qualitative analysis to elicit the information on the nature of the bulk molecular interactions of acetonitrile + aromatic ketone binary mixtures. IPC Code: Int. CI. 7 GOIN

Mixtures containing acetonitrile with and 11- and Grunberg-Nissan interaction constant (d') of heptane have been studied by Palmer and Smith I for binary liquid rrUxtures is useful in understanding the investigating excess volumes and excess enthalpies at nature of intermolecular interactions between two 318.15 K. Aminabhavi and Gopalakrishna2 have liquids. We have experimentally determined the studied the density, viscosity, and density and viscosity values of the binary systems of speed of sound of aquo-acetonitrile systems at 298.15 acetonitrile with acetophenone (Aph), propiophenone K. Sandhu et al. 3 reported excess molar volumes for (Pph), paramethyl acetophenone (Me-Aph) and binary mixtures containing acetonitrile and n-alkanol parachloro acetophenone (CI-Aph) in the laboratory. 4 (CI-CS) systems at 308.15 K, whereas Saha et al. The main aim of this study is to understand the studied viscosities of acetonitrile and binary interactions between unlike molecules of solvent and liquid mixtures at various temperatures. Nikam et al.s cosolvent binary systems. utilized the density and viscosity data of acetonitrile and various primary and secondary alcohols at Materials and Methods different temperatures to explain the molecular All the four ketones (Aph, Pph, Me-Aph and CI­ 6 interactions, while Ku and Tu that of acetonitrile and Aph) were purchased from SISCO, India, dried over l-chlorobutane. Krishnaiah et ae studied the speed of anhydrous potassium carbonate for three days, filtered sound for chlorobenzene and acetonitrile mixture, and then distilled 10. The middle fraction of di stillates 8 while Bakshi et al. reported various thermodynamic was retained and stored over 0.4 nm molecular properties for the liquid binary solvent mixtures of sieves II to reduce the water content, if any, and to acetonitrile with dimethyl acetamide, dimethyl avoid the absorption of atmospheric moisture and sulfoxide, nitrobenzene and methanol at 298.15 K. carbon dioxide gas. The purity of the ketones is 99%. Bakshi'i has also studied same properties for the High purity grade acetonitrile (99.5%) was systems of acetonitrile with ~-picoline, y-picoline, purchased from Merck (GR-India). It was dried with 2,6-lutidine, isoquinoline at the same temperature. To l2 0.3 nm molecular sieves . the best of our knowledge, density and viscosity study of acetonitrile with ketones is not reported up to now. Deionised water is distilled twice with the addition of little quantity of potassium permanganate and The study of excess parameters such as excess sodium hydroxide. Finally, it is distilled 13 over molar volume (0'), deviation in viscosity (~1l), excess H2S04. The electrical conductance of thus obtained Gibbs free energy of activation of viscous flow (C*E) water showed less than I x LO-6 ohm-I cm-I. 1]66 INDIAN J CI-IEM. SEC A. JULY 2005

Binary mixtures are prepared by mixing Table I - Compari ,on of experimental den sities (fJ) ~1I1 c1 appropriate volumes of th e liquid components in the viscosilies (11 ) of pure liquids wilh available lileralure speciall y designed glass bottles with airtight tetlon values al 298.15 K coated caps and th e mass measurements are p X 10-:1 11 x 10' performed on a Ohona 100 OS (India) single pan l Component (kg m·· ) (kg III I S·I ) analytical balance with a precision of ±O.O I mg. The required properties are measured on the same day Ex pI. Lit. E'(pl. Lit.

1 11 immediately after preparing each compositi on. The AcelOphenone 1.0231 1.0225 .\ 1.652 1.670 uncertai nty of the mole fraction is ±O.OOO 1. Propiophenone 1.0092 I.OOSi 6 1.7 65 A double-arm p ycnomete rl ~ with a bulb of 10 cm' and a capil lary of an internal diameter of about I 111m p-Melhy lace lophenone 1.001 6 1.823 is used to measure th e densities (p) of pure liqui ds p-Ch loroacelOphenone 1.1889 1880 16 2.615 and binary mixtures. The pycnometer is ca li brated by 17 using conductivity water with 0.9970 and 0.9940 Acelonilrile 0.7775 0.7768 0.368 0. 361 c g.cm-' as its densities at 298.15 and 308. 15 K, respective l y'~. The pycnometer filled with air bubble ± 0.0 I K for about 30 min to mtain th ermal free liquids is kept in a thermostat (lNSREF model eq uilibrium. The efflux time between Ihe marks 011 IRI -O 17C-lndia) with a thermal stability of ±0.01 K either side of th e bu lb is measured with a stop watch for 30 min to attain thermal equilibri um . The of ±0. 1 sec precision. The uncertainty of viscosity uncertainty in excess molar volume is observed to be values is ±0.5x I 0-5 kg m-I S-I. within ±0.005 x 10-6 m' mOrl. Experimental va lu es of density for the pure liquids are compared with known Results and Discussion values lS -17 at 298.15 K (Table I). The densities and viscosities of the mixtures of Ubbelohde viscometer5 having a capacity of about acetonitrile with Aph, Pph, Me-Aph and CI-Aph at 15 mL and the capi ll ary tube having a length of about 308. 15 K and their corresponding excess molar 90 mm and 0.5 mm internal diameter is used to vo lumes (V"). deviation in viscosities (L'l.I1), excess measure the flow times of pure li quids and liqu id Gibbs free energy of activation of viscous flow (C"E) mixtures. The viscometer is calibrated I~ with water an d Grunberg-Nissan interaction parameter Cd') along using the viscosity and density va lu es taken from the with the mol e fraction of ketones are given in Table 2. published values of ikam e { 01. 5 Viscosity va lu es (11) The excess molar vo lumes (0) have been of pure liquids and mixtures are calculated using th e evaluated from density using: relation:

... (2) 11 = (al - bl{) P ... ( I ) .. . (3 ) where '0' and 'b' are the characteristic constants of th e viscometer, p is th e density and { represents th e where Vm and Pmare the molar volume ancl density or tlow time. The flow time of pure liquids and liquid the mixture; XI, VI, MI and X 2, V and M2 are the mol e mixtures is measured. Viscometer constants are 2 fraction, molar volume and molecular 'vveigh t of pure obtained by measuring the flow times of water at four components I and 2, respectively. temperatures (298. 15 to 313.15) K at which values of 5 density and viscosity are known . A linear plot of The deviation in viscosity is calculated using the llf/P against {" facilitates the evaluati on of '0' and 'b' relation : 8 2 yielding 0 = 1.0862x 10- m" S-2 and b = -2.5000 m wi th a correlation coefficient of 0.99998. The . . . (-+ ) viscometer is then filled with the sample liquid by tilting the viscometer to about 30° from the verti cal where 11"" 111 and 11 2 are viSCOS iti es of the liquid and its limbs are closed with teflon caps to avoid th e mixture and of the pure components I and 2. evaporation. The viscometer is kept vertically in a respectively; XI and X 2 are th e mole fract ions of th e transparent walled bath with a thermal stability of pure components I and 2 in the liqu id slate. The SA VITHA JYOSTNA & SATY ANARA Y ANA: SOLVENT STUDIES OF ACETONITRILE-KETONE SYSTEMS 1367

Table 2 - Experimental densities (p), viscosities (T]), excess mo lar volumes (V\ deviations in viscosities (b1l), E excess Gibbs free energy of activation of viscous flow (C' ) and Grunberg-Nissan interaction parameter (d) at 308.15 K

3 3 6 3 3 x, P X 10 T] X 10 vE X 10 bTl X 10 C'Ex 10 d kg m·3 kg m" s" m3 mol" kg m" s·, N mol"

Acetophenone ( I) + Acetonitrile (2) 0.0000 0.7706 0.3052 0.0480 0.7968 0.3400 -0.0821 -0.0175 31.84 0.7673 0.1023 0.8233 0.3845 -0.1806 -0.0321 66.24 0.8230 0.1626 0.8493 0.4361 -0.2752 -0.0462 95 .65 0.8072 0.2321 0.8747 0.4959 -0.3270 -0.0621 117.33 0.7453 0.3113 0.9000 0.5746 -0.3819 -0.0696 139.30 0.7454 0.4024 0.9247 0.6736 -0.4218 -0.0699 154.80 0.7501 0.5125 0.9493 0.8002 -0.3917 -0.0632 157.38 0.7419 0.6426 0.9722 0.9514 -0.2209 -0.0537 137.25 0.7000 0.8018 0.9956 1.1436 -0.1098 -0.0348 88.54 0.6476 0.9135 1.0102 1.2843 -0.0496 -0.0158 42.20 0.6231 1.0000 1.0200 1.3943

Propiophenone (1) + Acetonitrile (2) 0.0000 0.7706 0.3052 0.0418 0.7934 0.3347 -0.0006 -0.0212 29.44 0.6298 0.0922 0.8178 0.3774 -0.0285 -0.0396 67.26 0.7702 0.1459 0.8412 0.4272 -0.1093 -0.0549 101.57 0.8208 0.2084 0.8649 0.4875 -0.2097 -0.0704 130.68 0.8127 0.2864 0.8898 0.5679 -0.3094 -0.0846 155.56 0.7908 0.3757 0.9136 0.6605 -0.4049 -0.1002 164.63 0.7224 0.4796 0.9360 0.7806 -0.4580 -0.1061 164.66 0.6806 0.6093 0.9575 0.9478 -0.3767 -0.0962 149.61 0.6549 0.7791 0.9786 1.1879 -0.1519 -0.0620 103.54 0.6353 0.9397 0.9952 1.4262 -0.0417 -0.0 184 32.38 0.6096 1.0000 1.0006 1.5177

p-Methylacetophellolle ( I) + Acetonitrile (2)

0.0000 0.7706 0.3052 0.0872 0.8160 0.3857 -0.1098 -0.0317 81. 12 1.1317 0.1449 0.8416 0.4411 -0.2555 -0.0505 116.78 1.0411 0.2088 0.8653 0.5094 -0.3527 -0.0645 150.42 1.0134 0.2823 0.8881 0.5871 -0.4213 -0.0813 170.98 0.9278 0.3756 0.9124 0.6989 -0.5198 -0.0896 188.15 0.8877 0.4771 0.9340 0.8260 -0.5843 -0.0931 187.59 0.8323 0.6125 0.9556 1.0009 -0.4792 -0.0924 161.60 0.7417 0.7811 0.9761 1.2351 -0.2797 -0.0751 101.98 0.6305 0.9146 0.9892 1.4540 -0.1218 -0.0280 46.37 0.6460 1.0000 0.9963 1.5919

p-Chloroacetophenone (I) + Acetonitrile (2) 0.0000 0.7706 0.3052 0.0513 0.8213 0.3576 -0.1835 -0.0528 46.84 1.1019 0.0920 0.8572 0.4065 -0.3386 -0.0873 83.39 1.1 808 0.1488 0.9003 0.4790 -0.4518 -0.1313 123.77 1.1582 0.2128 0.9415 0.5704 -0.5506 -0. 17 Il 160.35 1.1375 0.2863 0.9826 0.6742 -0.6213 -0.2179 177.89 1.0158 0.3792 1.0258 0.8301 -0.7035 -0.2525 193.61 0.9589 0.4876 1.0775 1.0385 -0.7697 -0.2663 188.98 0.9134 0.6196 1.1069 1.3099 -0.7092 -0.2655 165.32 0.8089 0.7847 1.1450 1.7156 -0.491 3 -0.1983 107.58 0.7285 0.8650 1.1602 1.9602 -0.3570 -0.1183 77.90 0.7901 0.9536 1.1748 2.2240 -0.1602 -0.0362 30.63 0.8467 1.0000 1.1813 2.3553 1368 INDIAN J CHEM, SEC A, JULY 2005

Table 3 - Adj ustable parameters (coefficients) (a) and standard devi ati ons (0 ) of acetonitrile + ketones at 308.15 K Binary system Property Coefficients Deviations 0 ao a l a2

Acetophenone ( I) + Acetonitrile (2) vEx \06 (m) mor l) -1.4941 0.8854 0.4227 0.1498 L'Hl x I 0) (kg m· 1 S·I) -0.2689 0.1029 -0.Q208 0.0125

C*Ex IO) (N morl) 623.7036 - \01.9508 -6.7246 13.84 13

Propiophenone ( I) + Acetonitrile (2) vEx \06 (m) morl) -1.7767 -0. 1061 1. 8 16 1 0.2212

~T] X \0 3 (kg m· 1 S·I) -0.4008 0.0829 -0.01 19 0.0262

C*Ex IO) (N morl) 680.5533 -135.9309 -4.9981 36.8175 p-Methylacetophenone ( I) + Acetonitrile (2) vEx \06 (m' 111 0rl) -2.2337 0.161 0 1.0142 0.2036

~T] x IO ' (kg n,-I S·I) -0.3923 0.0061 -0.0005 0.0260

C *Ex 103 (N mor l) 727.2290 -254.2380 99.8976 14.666 1 p-Chloroacetophenone ( I) + Acetonitrile (2 ) vEx l06 (m) mol·l) -2.893 1 0.2702 -0.9879 0. 1799

M1 Xl03 (kg m· 1 S·I) - 1.1066 0.0433 0. 1643 0.0781

C *Ex IO) (N morl) 760.7875 -201.5129 99.1 398 34.9207 excess Gibbs free energy of activation of viscous flow I (C*F.) is obtained by the equation:

.. . (5) where 'n' is the total number of experimental points and ' 111' is the number of coefficients considered (111=3 where Vm is the molar volume of the mixture, Rand T in the present calculation). The plots of excess molar have their usual meanings. volume and deviati on in viscosity versus mole fraction of ketones (XI) are shown in !Figs I and 2, respectively . Grunberg and Nissan 18 formulated Eq.(6) to assess the molecular interactions leading to viscosity The excess molar volume curves are almost changes: symmetric. All the isotherms at 308.15 K are parabolic in nature indicating negative deviations over ... (6) the entire range of mole fraction. The minimum value of each isotherm falls around the mole fraction XI = where d' is a constant. 0.5 indicating the formation of 1: 1 adducts (complexes) in all the systems. The excess properties l are fitted by the method of non-linear least squares to a Redlich-Kister type po Iynomla . 1 19 . The observed 0' values are the resultant of physical and chemical forces and they may be broadly recognised as: (i) The breaking of liquid order on .. . (7) mixing with the second component; (ii) Non-specific physical interactions and unfavourable interactions between unlike molecules; (iii) Specific interactions The coefficients Qj of Eq.(7) along with the standard appearing in the mixture between dissimilar deviation

Generally, the first two factors contribute for the When the electron density on oxygen atom of expansion of volume and the latter two factors ketoxy group is compared between p-chloro­ contribute to diminish the volume. From the acetophenone and p-methylacetophenone, the isothermal curves at 308.15 K shown in Fig. I, it is p-chloroacetophenone stands first. This is because the clear that in the case of ketones with acetonitrile, the unpaired electron pair on chlorine atom is more free volume reduction factors are preponderant. than the bonded electron pair of hydrogen atom. Hence, the p-chloroacetophenone must have hi gher All ketones are dipolar aprotic solvents. Similarly, electron density than p-methylacetophenone at the site acetonitrile is also dipolar aprotic solvent. of molecular interaction. The order of interaction for these three ketones would be: Acetonitrile, due to its high dipole moment (3 .92 D), l2 favours dipole-dipole interactions . Hence, there will be dipole-dipole interactions between unlike CI-Aph > Me-Aph > Aph molecules of all the systems, contributing to the reduction in the volume. Such trend in the case of In case of propiophenone, due to presence of ethyl acetonitrile with dipolar solvents is also reported in group, its +1 effect is more than acetophenone having literature2.7 . It shows that the specific interactions are methyl group. The greater +1 effect is experimenrally present between the mixtures of ketones and 20 confirmed on interaction energetic grounds . Based acetonitrile as indicated by Fig. I. on this consideration, the interaction position of propiophenone may fall between acetophenone and In addition to the above strong dipole-dipole p-methylacetophenone. Therefore, the total molecular interactions, there may be a possibility of charge interaction of four ketones would be: transfer complex formation between ketones and cyano group solvents. Nitrogen atoms are best donors 7 Cl-Aph > Me-Aph > Pph > Aph possessing lone pair of electrons on them. Hence, acetonitrile is a best electron pair donor to exhibit specific interactions with ketones. In p-chloro­ Experimentally observed vE values are also in acetophenone, the charge transfer complex formation similar lines of polarity conjecture mentioned above. is still predominant due to highly electronegative Hence, experimentally determined order of yE values chlorine atom present in it. Hence, the deeper minima (Fig. 1) further confirm the theoretical assumption of is observed in the isotherm of para the polarity of four ketones with the domination of chloroacetophenone. chemical forces between unlike molecules over the physical forces in all the systems.

In p-chloroacetophenone, there is a mesomeric A correlation between the sign of ~11 and yE has effect, i.e., conjugation between 1t-electrons of phenyl been observed for a number of binary solvent ring and unshared electron pair of · chlorine · ~ atom. systems, ~11 being positive where yE is negative or Though chlOline is having -I effe2f, 'the lmesomeric 2 1 vice versa • Figs I and 2 dearly indicate that the effect releasing electrons into benzene ring dominates isotherms of vE and ~11 do not obey the above generai over the -1 effect. Because of this reason, the electron statement. Therefore, the strength of the specific or density on the ketoxy oxygen of para dispersion forces is not the only factor influencing the chloroacetophenone IS greater than that of viscosity deviation of liquid mixtures. The molecular acetophenone. size and shapes of the components are also equally important. Therefore, Rastogi et al. 22 suggested that In p-methylacetophenone, there is a mesomeric the observed excess property is a combination of an effect due to hyperconjugation between hydrogen interaction and non-interaction part. The non­ atom of methyl substituent and 1t-electrons of phenyl interaction part in the form of the size effect can be ring. This is also ca])ed nobond resonance. Because of comparable to the interaction part and may be this reason, the electron density on the carbonyl sufficient to reverse the trend set by the latter. Based oxygen of p-methylacetophenone is greater than on this theory, the observed incongruity in the acetophenone. isotherms may be accredited to the size effect. 1370 INDIAN J CHEM, SEC A. JULY 2005

~--~--~-----~------~ 0.2 0.' 0 .• D. •

-il.!

.0.05

-<1 .2

-<1.3 .0.1

L.. o E -<1 .4 co "E ~ -0.15 .-o - -<1 .5 ..>" .0.2 -<1.6 I -<1.7

-<1 .8

·0.9.L------' ~L J---.-.J Mole fraction of ketone, lCj Mole fraction of ketone, X,

Fig. 1 - Variation of VE of the binary liquid mixtures of Fig. 2 - Variation of L'i11 of the binary liquid mi xtures of acetonitrile with Aph (0 ); Pph (.); Me-Aph (+) and acetonitrile with Aph (0); Pph (.); Me-Aph (+) and CI-Aph (e ) at 308.15 K. CI-Aph (e) at 308.15 K.

In order to elucidate the forces that are acting different factors. Moreover, slight higher values of between unlike molecules, the help of excess Gibbs excess Gibbs free energy of activation of viscous flow free energy of activation of viscous flow (G*E) and (G*E) and Grunberg-Nissan interaction parameter Cd) Grunberg-Nissan interaction parameter (d) has in Table 2 for p-methylacetophenone than become indispensable and quintessential. The positive propiophenone is an indication of its higher molecular G*E values indicate specific interactions while interactions than propiophenone. negative values indicate the dominance of dispersion forces; if d values are positive, the interactions Acknowledgement between unlike molecules are strong whereas weak 23 with negative values ,24, The values of Table 2 Sincere thanks are due to Dr K N S Kashi incontrovertibly indicate that G*E and d are positive Viswanadham, Professor of Mathematics, National for all the systems over the entire range of mole Institute of Technology, Warangal, for his assistance fraction, Hence, a cerebral conclusion can be made in calculating the coefficients of poly nominal that chemical forces are dominating over the physical equation of various degrees through non-linear forces in all the systems, regression analysis.

The negative tJ.T) values at equimolar References concentrations of acetonitrile and ketones follow the Palmer D A & Smith B D, J Chern Eng Data. 17 (1972) 71. order: 2 Aminabhavi T M & Gopala Krishna B, J Chern Eng Data. 40 (1995) 856. 3 Sandhu J S, Sharma A K & Wadi R K, J Chern Eng Data, 3 1 CI-Aph > Pph > Me-Aph > Aph (1986) 152. 4 Saha N, Das B & Hazra D K, J Ch.ern Eng Data. 40 (\994) The trend is the same in over all order, 1264. p-chloroacetophenone being highest and 5 Nikam P S. Shirsat L N & Mehdi Hasan. J Chern Ellg Data. acetophenone lowest, when yE and 8rl values are 43 (\ 998) 732. compared. Propiophenone is exhibiting anomalous 6 Ku H C & Tu C H, J Chern Eng Data, 43 ( l998) 465. 7 Krishnaiah A, Rao D N & Naidu P R, Indian J Chem, 21 A behaviour among these two properties. An inter (1982) 290. comparison of yE and tJ.T) supports the contention of 8 Bakshi M S, Singh J, Kaur H. Ahmad S T & Kaur G, J Chem 25 Kaulgud that the two properties are determined by Eng Data, 41 (1996) 1459. SAVITHA JYOSTNA & SATYANARA Y ANA: SOLVENT STUDIES OF ACETONITRILE-KETONE SYSTEMS 1371

9 Bakshi M S, J Chem Soc Faraday Trans 89 (1993) 3049. 17 Covington A K & Dickinson T, Physical Chemistry of 10 Mahl B S, Kaur H, Singh H P & Khurma J R, Thermochim Organic Solvent Systems (Plenum Press, London and New Acta, 99 (1986) 291. York) 1973, Chap 1. 11 Riggio R, Ramos J F & Martinez H E, Call J Chem, 79 18 Grunberg L & Nissan A H, Nature, 164 (1949) 799. (2001) 50. 19 Redlich 0 & Kister A T, Ind Eng Chern, 40 (1948) 345. 12 Paez S & Contreras M, J Chem Ellg Data, 34 (1989) 455. 20 Francesconi B, Comelli F & Costellari C, J Chem Eng Data, 13 Nikam P S & Sawant A B, J Chem Ellg Data, 42 (1997) 43 (2000) 514. 1151. 21 Fort R J & Moore W R, Trans Faraday Soc, 62 (1966) 1112. 14 Nikam P S, Mahale T R & Mehadi Hasan, J Chern Ellg Data, 22 Rastogi R P, Nath J & Misra J, J Phys Chern, 71 (1967) 43 (1998) 436. 1277. 15 Lien P J, Venkatesu P, Lin H M & Lee M J, J Chern Ellg 23 Reed m T M & Taylor T E, J Phys Chern, 63 (1959) 58. Data, 47 (2002) 768. 24 Meyer R, Meyer M, Metzger J & Peneloux A, J Chirn Phys 16 The Merck Ilidex, edited by S Budavari (Merck Research Phys Chirn Biol, 63 (1971) 406. Laboratories Division, USA) 1996. 25 Kaulgud M V, Z Phys Chern (Frankfurt), 36 (1963) 365.