Platinum Metals Review

PLATINUM METALS REVIEW

A quurterly survey of research on the platinum metuls and of dwelopments in their applications in industry

VOL. 14 OCTOBER 1970 NO. 4

Contents

Platinum Containers for the Growth of Single Crystal Oxides 118

Platinum Inclusions in Laser Glasses 122

Rhodium Plated Langmuir Probes for Sounding Rockets 123

Platinum and the Refractory Oxides 124

Combined Catalysts for Ammonia Oxidation 130

Absorption of Hydrogen by Palladium Alloys 131

Platinum-Carbon Catalysts with Molecular Sieve Properties 133

Platinum Metal Coatings for Stereoscan Specimens 139

The History of Matthey Bishop 140

Abstracts 147

New Patents 156

Index to Volume 14 159

Communications should be addressed to The Editor, Platinum Metals Review Johnson, Matthey & Co Limited, Hatton Garden, London ECl P 1 AE Platinum Containers for the Growth of Single Crystal Oxides

By L. G. Van Uitert Bell Telephone Laboratories Incorporated, Murray Hill, Kew Jersey

The growth of single crystal oxides for optical and magnetic purposes is commonly carried out using platinum containers. ilIodijications to container design have been important factors in improving growth conditions. A new composite three-layer crucible has been fabricated in platinum and iridium for growing crystals of sodium barium niobate, and a platinum container which can be drained of jlux has been developed for growing rare earth iron garnets.

Single crystals are of basic importance as taker design. A melt (or fused mixture of the integral parts of semiconductor devices, components of a crystal) can conveniently be oscillators, transducers, detectors, delay lines contained in a platinum crucible-susceptor and power limiters. There is also an interest that is heated by radio frequency induction. in nearly perfect optical crystals for coherent In Fig. z a boule of lead molybdate (PbMoO,), light sources (lasers), non- linear optical applications (second harmonic generators and parametric oscillators) and as light beam modulators, de- flectors and phase shifters. Further, there are a number of uses for large, uniform, single crystals of yttrium or rare earth iron garnets having controlled magnetic properties. The emphasis placed on size and uniformity has moti- vated a search for ways to improve crystal growth. One important part of this effort has been to modify the con-

Fig. 1 The furnace in which single crystal garnets are grown in a platinum crucible. The operator is preparing to drain 08the $ux by puncturing the seal in the container bottom

PZutinumMetuZsRev., 1970, 14, (4), 118-121 118 Fig. 2 A single crystal of lead molybdate being pulled from the melt. The platinum crucible susceptor is heated by a radio frequency induction coil, the top turn of which is visible here

which is particularly useful for acousto-optic applications, is shown being pulled from a melt contained in a platinum crucible that is 3 inches in diameter and 3 inches high (I). The crucible is embedded in zirconia granules that are contained by a quartz liner that is closely fitted by a multi-turn r.f. coil (only the top turn is evident). Little difficulty is encountered with the been used to grow NaBa,Nb,O,, crystals for crucible in growing PbMoO, (melting point about 50 hours. This crucible has expanded 1065°C). However, when growing sodium to nearly twice its original volume. The third barium niobate (NaBa,Nb,O,,, an important (C) is a new, composite, three-layer crucible. material for non-linear optical applications) It was constructed by close fitting a 0.040 the platinum crucible expands extensively inch wall platinum crucible inside a 0.040 over the several hours required to complete inch wall iridium crucible which in turn was the growth run (2). This shortens the useful close fitted inside a 0.020 inch wall platinum lifetime of the crucible and increases the crucible. The inner and outer platinum difficulty of maintaining uniform crystal crucibles were joined at the top. The growth conditions. The melting point of fourth crucible (D) is such a container after NaBa,Nb,O,, is near 145o"C, about 285°C 20 hours of use. The outer wall expanded due closer than that of PbMoO, to the melting to internal gas pressure and subsequently point of platinum at 1773°C. It is essential burned through. The fifth crucible (E) was to use platinum in contact with the also constructed in the same manner as NaBa,Nb,O,, melt, rather than the higher crucible C. However, several tiny vent melting point noble metals (such as rhodium holes were drilled through the outer platinurn or iridium) to avoid contamination by oxides layer to permit entrapped gas to escape of the latter that colour the crystal. For- during heating. The crucible shown (E) has tunately, the surface stability of platinum can been used to grow NaBa,Nb,O,, crystals for be combined with the rigidity of iridium by more than zoo hours without expanding or using composite crucibles. suffering distortion beyond that experienced Several crucibles are shown in Fig. 3. The using iridium alone as the crucible material. first (A) is a new 1.5 inch diameter x 1.5 inch Crystals that do not grow well from the height x 0.060 inch wall platinum crucible. melt are often best prepared by growth from The second (B) is a similar crucible that has a solvent or flux. The yttrium or rare earth

Platinum Metals Rev., 1970, 14, (4) 119 Fig. 3 Platinum and composite platinum-iridium-platinum trilayer crucibles compared. A New platinum crucible B Platinum crucible after 50 hours growing sodium barium niobate crystals C New composite crucible D Composite crucible after 20 hours use E Composite crucible with vent holes to permit escape of entrapped gas during heating. Afier 200 hours use it was distorted no more than one made of iridium

Fig. 4 A platinum container used for the jlux growth of large garnet crystals has been designed to permit draining at high temperatures

Platinum Metals Rev., 1970, 14, (4) 120 Fig. 5 Garnets grown by the technique which includes draining of thejux are used in microwave devices, delay lines, tunable lasers and bubhle domain devices. Demand for them is increasing steadily iron garnets (e.g. Y,Fe,O,,) are such crucible is mounted on a hollow pedestal in a materials. These crystals are grown by vertical muffle resistance furnace during slowly exsolving the crystal components from crystal growth. The operator shown in Fig. I a PbO.PbF,*B,O, flux by cooling at about is preparing to drain the flu by puncturing 15°C per day from 1300OC to 950°C (3). the seal in the bottom of the container. The Below the lower temperature the garnets flux drains quietly into the catch tray. After tend to redissolve and therefore they should the flux is drained the furnace is shut down be separated from the flux. However, large and allowed to cool to room temperature. crystals will crack if they are subjected to Garnets that have been grown under these thermal shock. This can be avoided by re- conditions are shown in Fig. 5. The crystals moving the flux at 95OUcwhile the crystals have found use in microwave devices, delay remain in the furnace. lines, tunable lasers and bubble domain A platinum container that has been de- devices. signed to permit draining at high tempera- References tures is shown in Fig. 4. The 8 inch diameter I D. A. Pinnow, L. G. Van Uitert, A. W. x8 inch height xo.060 inch wall container Warner and W. A. Bonner, Appl. Phys. Letterx, 1969,15, 83-86 weighs about pounds. The hole in the 15 2 L. G. Van Uitert, J. J. Rubin and W. A. centre leads into a 4 inch long stand-off that can Bonner, IEEE Trans., 1968, QE-4, 622-627 be fitted with a welded-in insert. The insert is 3 W. H. Grodkiewicz, E. F. Dearbom and L. G. Van Uitert, 3. Phyr. Chem. Solids, 1967, punctured to drain off the flux. The covered 441-444

Platinum Metals Rev., 1970, 14, (4) 121 Platinum Inclusions in Laser Glasses THEIR ORIGIN AND PREVENTION

For some years it has been known that a platinum crucibles, platinum heating elements few particles of platinum may be found in all or thermocouples, and are conveyed as vapour optical glasses which have been melted in to the molten glass. The evidence for this is systems containing platinum. These have that platinum particles were not found in never been observed to affect the performance glasses which had been melted in platinum of even the most critical of lenses but in 1963 in an atmosphere of pure nitrogen, even after it was discovered at the American Optical they had been kept molten for 90 hours at Corporation that in laser rods operated at high 2,45O0C. Moreover, in an experiment in peak powers they may absorb so much which a stream of oxygen was passed through energy as to cause explosive fracture. a horizontal tube furnace over a sheet of The particles, as described by Richard F. platinum and then over a ceramic crucible Woodcock in a report (I) of investigations in containing molten glass, both side by side, the Central Research Laboratory of the particles of platinum were found in the glass. American Optical Corporation at South- The investigators, however, were not able to bridge, Massachusetts, are generally lacy and establish the mechanism by which the lacy irregular in shape with rounded globular particles of metallic platinum were formed in contours. They may be so small as only just the molten glass from the gaseous oxide in the to be resolved by the optical microscope- atmosphere above. On the other hand, they about 2 pm across-and exceptionally they showed that satisfactory laser glass, free from may be as large as 500 pm. Even the smallest particles of metallic platinum, was obtained particle may cause damage. from glass melted in platinum crucibles when oxygen was rigidly excluded and an atmos- Possible Origins phere of pure nitrogen was maintained in the Several possible sources of the particles furnace. were considered in the investigation and were rejected. They are of the wrong shape to have Methods of Prevention been torn off by abrasion and no evidence In applying these findings to production, was found to support a fanciful suggestion there was rightly concern over the possibility that they might be the debris from grain that platinum crucibles might be contamin- boundary attack which it was thought ated by such elements as antimony and zinc, might also detach protruding grains “forced reduced from the melt, but there was no up by grain growth”. Moreover, the possibility consistent evidence of such damage. In the that they might be precipitated from solution event, it was found that it was possible fairly of platinum in the glass was ruled out by simply to modify an existing 50 lb. platinum- tests which indicated that the solubility of lined extruder furnace so as to maintain over platinum in laser glass is less than one part in the melt an atmosphere of nitrogen containing IO~O. It was established that neither the size about I per cent of oxygen. Several satis- nor the shape of the particles is affected by factory bars of laser glass were made in this long heat-treatment at temperatures up to way; but it is indicated that further work to the softening point of the glass. determine the optimum oxygen content- The most probable explanation is that they and to control it-is desired. are derived from platinum oxide, PtO,, Concurrently work was carried out to formed by oxidation of the free surfaces of the develop an all-ceramic melter. Some progress

Platinum Metals Rev., 1970, 14, (4), 122-123 122 is reported but the best melts showed various with the even hotter platinum heating degrees of striae. elements. Hence the question arises as to This report provides strong evidence that whether it might be possible to protect the the platinum particles do not derive from glass melt from contact with PtO, vapour attack by the molten glass on the platinum simply by provision of a reasonably close- crucibles but from decomposition of PtO, fitting cover or lid. It would seem well vapour in the atmosphere above the surface. worth a trial. J.C.C. And this PtO, vapour almost certainly will Reference originate through the reaction of oxygen with I Preparation of Platinum-free Laser Glass, US. the hot outside surface of the crucible and Rept. .4D6vj504, 1969, (Aug.1, 48 PP.

Rhodium Plated Langmuir Probes for Sounding Rockets

Rhodium-plated spherical Langmuir probes for the measurement of electron densities at high altitudes. The sector plates are used for calibration purposes

At the Radio and Space Research Station, that these probes have a very uniform Slough, rocket payloads are built for in- surface contact potential; also spurious vestigation of the production and density of signals, due to photoemission of electrons ionisation in the D-region of the ionosphere from the surface by the sun’s radiation, must at altitudes between 65 and 100 Mometres. be made insignificant. For these reasons it is Several different experiments are combined necessary for the probes to be rhodium in each rocket flight, and one of these is a plated and to be kept uncontaminated until spherical Langmuir probe for measurement they are exposed to the upper atmosphere. of electron density. Radio and Space Research Station The probe consists simply of a conducting Langmuir probes plated by Johnson Matthey sphere, to which a programmed voltage is Chemicals Limited have already been flown applied. The current to the probe, due to successfully on twelve flights of British collection of electrons from the ionosphere, “Petrel” research rockets and a similar is measured and used to find the electron number are to be flown in 1970-71. The density as a function of height. It is essential plating work is again by Johnson Matthey.

Platinum Metals Rev., 1970, 14, (4) 123 Platinum and the Refractory Oxides 111 -CONSTITUTIONAL RELATIONSHIPS IN THE ALLOYS FORMED By A. S. Darling, G. L. Selnian and R. Rushforth Research Laboratories, Johnson Matthey & Co Limited

platinum with aluminium, zirconium, mag- Platinum reacts exothermically with nesium and thorium have been carefully aluminium, zirconium and thorium, examined. In the course of this work the but is very reluctant to alloy with solubilities of aluminium and zirconium in magnesium. It dissolves 2.2 per cent platinum have been accurately established by weight of aluminium at 1500°C and for the first time. 10 per cent by weight of zirconium at 1650°C. These wide solid solutions are Aluminium-Platinum Alloys in equilibrium with very stable inter- The presently accepted diagram for this metallic compounds, thus accounting system is based on the work of Huch and for the severe reactions which can occur Klemm (2) who concluded that the first when platinum is heated in contact compound to form when aluminium is added with alumina and zirconia. Zirconium to platinum is Pt,Al which reacts with the reacts peritectically with platinum. The primary solid solution to form a eutectic egects of these refractory decomposition melting at 15o7’C. The compound itself processes on the long-term stability of melted at 1556°C and Huch and Klemm were platinum thermocouples will be dis- concerned largely with the identification of cussed in the fourth and concluding intermetallic phases and the establishment article in this series. of solidus and liquidus temperatures. Edshammar (3) commented on the rapid and exothermic reaction which occurred when The extent to which reactions occur when platinum and aluminium were melted to- platinum is heated in contact with the more gether on a water-cooled copper hearth, refractory oxides depends very largely upon although the heats of formation have been the affinity of platinum for the metal released determined only in the palladium-aluminium by the refractory. Qualitative indications of system (4). the dominance of this effect are provided by As part of our compatibility work the the extreme reluctance of magnesia to dis- phase boundary of the platinum-rich primary sociate in the presence of platinum (I). The solid solution has been accurately established position of the phase boundaries in the alloys in these laboratories. Arc melted ingots, which are formed provides a rather more prepared from “Thermo-pure” platinum and reliable index of the activity of the dissolved “Spec-pure” aluminium were homogenised metal. Data obtained in this way, although for six hours at 1450°C in vacuum, rapidly not particularly accurate, assist in the rational quenched and then analysed by chemical interpretation of experimental findings, and methods. The hardness and microstructures in our attempts to understand the general of these alloys are given in Table I. principles of refractory decomposition con- The alloy containing 3.18 per cent of stitutional relationships in the alloys of aluminium appeared to be close to the eutectic

Platinum Metals Rev., 1970, 14, (4), 1244130 124 Fig. 1 Alloy containing 2.16 pcr cent aluminium Fig. 2 Alloy containing 2.16 per cent aluminium quenched after 6 hours at 1450°C. x 300 quenched after a1urther 3 hours at 1470°C. 'x 300 composition. At 1450°C the 2.16 per cent to establish the solubility boundary, most of aluminium alloy had a finely dispersed this information was derived from the electron precipitate which dissolved completely when probe micro-analysis of duplex alloys heated to 147o"C, as shown in Figs I and 2. quenched over a wide range of temperature. Although metallography of this sort helped Metallographic methods were, however, used for solidus determinations and it was Table I found that very small quantities of quenched liquid could be detected. Fig. 3 shows the Aluminium duplex structure of the 3.18 per cent alu- Content in Wt.% HvlOO gm Structure minium alloy quenched from 147o'C. Liquid Nominal Analysed was first detected in this alloy at 1510°C as 0.5 0.52 124 Single phase shown in Fig. 4. This eutectic temperature I .o 1.06 148 Single phase agrees well with the I507'c quoted by Huch and Klemm (2). The revised diagram based 2.0 2.16 320 Fine precipitate on metallographic observations and electron 3.4 433 Coarse duplex 3.18 probe microanalysis is shown in Fig. 5. 4.0 4.1 8 464 Coarse duplex Fig. 4 Quenched liquid round the grain bound- Fig. 3 Structure of the 3.18 per cent aluminium- aries of the 3.18per cent aluminium-platinumalloy platinum alloy quenchedfrom 1470°C. x 300 quenched from 151 0°C. x 1000

Platinum Metals Rev., 1970, 14, (4) 125 WEIGHT PER CENT ALUM1 N IUM Aluminium reduces the lattice spacing of 1 2 3 4 5 1800 O( platinum from 3.9231A to 3.912& when I WEIGHT PER CENT ALUM1 N IUM per cent by weight has been taken into 1700 solution. The compound Pt,Al which I 1600 I separates out at higher concentrations has a primitive cubic structure of the Cu3Au type. 1500 3 Our value of 3.879A for the spacing of this 1400 phase agrees reasonably well with the 3.876A quoted by Klemm, although our values for the 1300 parameters of the platinum-rich solid solution 1200 II 1 II I (( A in this two-phase region are somewhat anomalous. These variations may perhaps be 1100 associated with the presence of an ordered 1000 phase, first mentioned by Bronger and

1 Klemm (5), who suggested its formation at 900 I I temperatures below 1300’C in the duplex i 800 I I region by reaction between Pt3A1 and the I A primary solid solution. Confirmatory work 700 I I I is obviously required in this region. 600 I I I 4, A Zirconium-Platinum Alloys 500 5 10 15 20 25 30 The zirconium-platinum diagram, based on ATOMIC PER CENT ALUMINIUM the work of Kendall, Hays and Swift (6), shows Fig. 5 Platinum-rich end of the aluminium- that the solubility of zirconium in platinum is platinum diagram bused on the present work. less than I per cent by weight although little 0 Single phase alloys A Two phase alloys metallography was carried out in this region. 7 Incipient melting Complete liquid The compound Pt,Zr had a melting point in 0 Electron probe microanalysis of two phase alloys excess of 2120’C and Raman and Schubert (7) Some lattice parameter measurements ob- concluded that it had a hexagonal TiNi, tained on alloys quenched from 1450°C are structure with a=5.624A and c-g.213A. given in Table 11. Powder obtained by filing The zirconium solubility values were quenched ingots was stress relieved for six obviously in error, however, as it was known minutes at 800°C for this X-ray examination. that platinum containing up to at least 2 per cent by weight of zirconium has a single Table II I phase structure and can be readily rolled and Alloy drawn into wire. In order to establish the true composition Lattice Lattice type solubility of zirconium in platinum, alloys At 1 1 Wt.% parameter A containing up to 14 per cent by weight of 3.9177 F.C.C. zirconium were made up in the arc furnace 3.9124 F.C.C. from “Thermo-pure” platinum and “Spec- pure” zirconium rods, the latter having a 3.9073 F.C.C. total impurity content less than 0.01 per cent. 3.881 6 Primitive cubic Considerable heat was evolved when these ti 3.917 F.C.C. metals began to run into each other under the 3.879 Primitive cubic arc. Table I11 indicates the composition, microstructure and hardness of these alloys Pure Pt 3.9231 F.C.C. after homogenisation for 16 hours at 1650°C in vacuum followed by quenching in silicone oil.

Platinum Metals Rev., 1970, 14, (4) 126 The 12 per cent zirconium alloy, after quenching from 1650°C contained two well defined phases, the general appearance of which was more reminiscent of a peritectic than a eutectic microstructure. The metallographic work demonstrated quite con- clusively the extremely narrow range of the duplex region between the platinum-rich primary solid solution and the compound Pt,Zr. Fig. 6 illustrates the heavily twinned solid solution alloy containing 9.77 per cent by weight of zirconium after quenching from 1650°C. The 12 per cent zirconium alloy shown in Fig. 7 contains 20 to 30 per cent by volume of the zirconium-platinum intermetallic, while the alloy containing 13.5 per cent of zirconium shown in Fig. 8 consists almost entirely of the compound Pt,Zr. The platinum-rich solid solution in this alloy could just be detected by X-ray methods. The lattice parameter measurements for the hexagonal structure agree with those of Wallbaum (8) but not Schubert (7). Several solidus determinations were made on alloys heated in vucuo in a tantalum resistance furnace. The specimens were suspended on tungsten-rhenium wires and quenched in silicone oil. Micro examination of these quenched specimens showed that the platinum-rich end of the diagram was of the peritectic type rather than a eutectic as had been hitherto suggested. The present experimental results, supple- mented by Kendall's (6) melting point determinations, have been plotted on Fig. 9 which provides a self-consistent interpretation of the data available. Further work is obviously required to establish the true shape of the solubility curve at lower temperatures and to ascertain over what range of compositions Fig. 6 Heavily twinned microstructure of solid the Pt,Zr phase exists. solution platinum alloy containing 9.77 per cent by weight of zirconium quenched from 1650°C. x 300 Thorium-Platinum Fig. 7 Duplex alloy containing 12.00 per cent by weight of zirconium afer quenching from 1 G50'C. The diagram advanced by Thomson (9) x 300 shows the formation of a eutectic between Fig. 8 Platinum alloy containing 13.5 per cent Pt,Th and platinum at a temperature of by weight of zirconium afer quenchingfrom 1650°C. 1337"&12~C. The solubility of thorium in This alloy consists almost entirely of the compound Pt,Zr. x 300 platinum was not determined.

Platinum Metals Rev., 1970, 14, (4) 127 WEIGHT PER CENT ZIRCONIUM :li~ooI 1, 2 3 4 5 6 ? 8 9 1: 1) 72 1: '4 15 16 j7

2200 0 I

" I 1700 4 11 I

1600 Ill 1500 ' ,1 ; , 1 />! I 0 5 10 15 :!20 25 30 lo ATOMIC PER CENT ZIRCONIUM ' Fig. 10 Microstructure of platinum which fused completely ajler contact with thorin for 1 hour at Fig 9. Revised diagram for the platinum-rich end 1700°C in pure argon. x I50 of the zirconium-platinum system. 0 single phase alloys A Two phase alloys 0 Complete liquid V liquid and solid Very severe reactions occurred, however, when platinum was heated in contact with thoria under a pure argon atmosphere. In view of the very deleterious effects Fig. 10 illustrates the microstructure of a which thoria can have upon platinum, the specimen which fused completely after three microstructure and composition of the alloys hours at 1700OC under these conditions. formed has received considerable attention. The melting point of Pt5Th, suggested as No evidence of thorium solubility in the being somewhat higher than 150o0C (9) does primary crystals has been detected with the not in itself indicate an extremely high electron probe micro-analyser although this stability. High heats of formation are cannot be regarded as conclusive evidence obviously associated with the exothermic since the limit of detection of thorium in reactions which occur wherever thorium and platinum by this technique is found to be platinum are melted together. The high approximately 0.2 per cent by weight. mutual affinity of the two metals reflects itself

Table 111

Analysed composition Hardness Microstructure Phase Lattice % by weight of Zr Hv 1OOg parameters

0.87 152 Single phase F.C.C. 1.04 3.05 39% F.C.C. 3.9ssA 4.97 45s F.C.C. 1 3.9608, 9.77 844 F.C.C. (Heavily twinned) 12.00 845 Duplex F.C.C. 13.50 846 Almost completely H.C.P. a= 5.664A single phase H.C.P C= 5.664A

Platinum Metals Rev., 1970, 14, (4) 128 therefore in the ability of platinum to ac- celerate the decomposition of thoria. The reactions which occur must, however, be carefully distinguished from these between aluminium and zirconium with platinum. In the absence of detectable solubility any elementary thorium which contacts platinum above 1337°C will immediately form liquid. Diffusion in the liquid state is rapid, so that thin liquid eutectic films on the platinum surface could expedite the transfer of thorium from the surface of the platinum to its interior. The only essential requirement Fig. 11 Microstructure of platinum contuining 1.5 per cent by weight of mugnesium afer hono- for such a reaction is a stable liquid phase genisation for 16 hours at 1400°C followed by capable of retaining dissolved thorium in a quenching. x 75 state of low activity. evacuated platinum tube by pressure welding. Magnesium-Platinum After soaking for 16 hours at 1400°C the Bronger and Klemm (5) were able to capsule was quenched into water, its com- produce magnesium-platinum alloys by reduc- position being then checked by micro-probe ing magnesia in contact with platinum with analysis. No compound was detected in this carefully dried ammonia. The reductions alloy, which contains 11 atomic per cent of proceeded further and more completely at magnesium and falls just within the region of IIOO'Cthan at 1200 to 1400°C and at these possible ordering described by Bronger and lower temperatures platinum solid solutions Klemm (5). As quenched from 1400OC this containing up to 28 atomic per cent of alloy had a hardness of 225H, (258). magnesium were obtained. Two ordered phases, based on the compositions Pt,Mg Conclusions and Pt,Mg were detected within this solid Platinum reacts exothermically with alu- solution field. minium, zirconium and thorium, and this Magnesium-platinum alloys are not readily tendency towards compound formation pro- obtained by conventional melting methods. vides the driving force for the refractory Large quantities of magnesium are lost by decomposition processes which can occur evaporation and exothermic reactions such at high temperatures. The affinity of platinum as those between aluminium and platinum for magnesium is low and magnesia shows, do not occur. Even by their direct reduction therefore, little tendency to decompose on method Bronger and Klemm were unable to heated platinum surfaces. produce magnesium-rich alloys and we must The solubility of aluminium in platinum conclude that platinum and magnesium alloy is much higher than had hitherto been with extreme reluctance. supposed and the ability of solid platinum Fig. 11 illustrates the microstructure of a to dissolve 10 per cent by weight of zirconium platinum alloy containing approximately I .5 is particularly noteworthy. When saturated, per cent by weight of magnesium. This this solid solution is in equilibrium with the alloy was made by argon arc melting, and of compound Pt,Zr. At lower concentrations the 3 per cent of magnesium added only the dissolved metal is held in a state of activity half remained. To avoid loss of magnesium even lower than that which exists in the during homogenisation the ingot was packed compound. As evidenced by the decomposi- in magnesia powder and sealed up in an tion processes which have been observed, the

Platinum Metals Rev., 1970, 14, (4) 129 affinity for zirconium of very dilute zir- Acknowledgements conium-platinum alloys appears to be very Acknowledgements are due to the United Kingdom Atomic Energy Authority who sup- formidable indeed. ported and stimulated much of this work. We Although thorium is almost completely are particularly indebted to Mr J. P. Evans and Dr L. E. Russell of the Process Technology insoluble in solid platinum, the heat that is ~i~i~i~~at ~~~~~llfor their help and encourage- evolved when liquid alloys are formed con- ment, and to Mr G. Booth for his skilled experimental assistance. firms the very high affinity of platinum for thorium. In the absence of terminal solid References solubility any thorium vapour which meets a I A. S. Darling, G. L. Selman and R. Rushforth, Platinum Metals Rev., 1970, (3), 95 platinum surface at temperatures above 14, 2 R. Huch and W. Klemm, Z. Anorg. Allgem. 1337‘C will immediately form liquid. The Chem., 1964, 329, (I-6), 123 presence of such a liquid layer on a solid 3 L. E. Edsharnmar, Diss., Inst. Inorg. and Phys. Chemistry, University of Stockholm, May 1969 platinum surface would be expected to 4 R. Ferro and R. Capelli, Atti Accad. NuzZ. facilitate metal transfer processes. Linzei, 1963, 34, 659 The practical implications of these re- 5 W. Bronger and W. Klemm, 2. Anorg. Allgeni. ChW., 1962, 319, 58 fractory decomposition processes for the 6 E. G. Kendall, C. Hays and R. E. Swift, long-term stability of platinum thermo- Trans. Met. SOC.AIME, 1961, 221, 45 couples when in contact with various re- 7 A. Raman and K. Schubert, 2. Metallk., 1964, 55,704 fractories will be discussed in the final article 8 H. J. Wallbaum, Naturwissensch., 1943, 31, 91 in this series. 9 J. R. Thomson,J. Less-Common Met., 1964,6,3

Combined Catalysts for Ammonia Oxidation PLATINUM ALLOY GAUZES IN NITRIC ACID PRODUCTION

Oxidation of ammonia over platinum alloy Tests were carried out at pressures of 5 gauzes remains the most efficient method of and 10atmospheres and at I 150K using a pad producing oxides of nitrogen in nitric acid of seven palladium-rhodium-platinum gauzes plants. However, studies in Russia have been and a layer of 93 per cent Fe,O, - 7 per cent directed towards replacing part of the pad of Cr,O, catalyst of thickness varying from platinum alloy gauzes used in the conven- 120 to 270 mm. The amount of ammonia tional reactor by non-platinum metal catalysts. conversion at the platinum alloy gauze was 81 As long ago as 1958 Russian workers showed per cent at 5 atm, and 78 per cent at 10 atm. that combined catalysts, consisting partly of As the layer of iron-chromium oxide in- gauzes and partly of a layer of another catalyst, creased in thickness the total conversion were effective in ammonia oxidation, thereby rose from 91to 97 per cent at 5 atm, and from reducing both the amount of platinum alloy 87 to 94.5 per cent at 10 atm, i.e., a greater gauze required and the loss of platinum metal thickness of the non-platinum metal catalyst from the gauze during the reaction. bed results in greater conversion, as might A. P. Zasorin, N. F. Kleshchev and V. I. have been expected. Atroshchenko have now shown (Khim. The authors suggest that a layer of oxide Promyshlennost’, 1970, (7), 513-514) that a catalyst 25 to 30 mm thick is equivalent to layer of iron oxide-chromium oxide catalyst one platinum gauze, a layer 120 mm thick to can be used in conjunction with platinum 4 to 5 gauzes; 270 mm thick, 9 to 11 gauzes. alloy gauzes in high pressure ammonia The normal practice of the authors ap- oxidation plants. Most of the conversion still pears to have been to use a pad of from 16to takes place on the platinum alloy gauze and 19 gauzes at these pressures. They now the total yield of the combined catalysts is suggest that a pad of 6 to 7 gauzes with a somewhat less than where gauzes alone are catalyst bed 200 to 220 mm thick is adequate used but if economic considerations dictate at 5 atm, and that a bed of oxide catalyst. 300 the use of less platinum then the studied to 330 mm thick is adequate with the same method is a practical proposition. number of gauzes at 10 atm.

Platirium Metals Rev., 1970, 14, (4) 130 Absorption of Hydrogen by Palladium Alloys PAPERS AT THE WARSAW SYMPOSIUM

pearance, and high diffusivity of hydrogen. Interest in the absorption of hydrogen A brief outline was given of the theoretical by palladium and its alloys continues and practical reasons for investigations of the at a high level. A symposium on this palladium alloy-hydrogen systems which subject was held in Poland in Jub and have so far been studied, and also to the possibility of advantages to be obtained from is reported here, while a further meeting extensions in this field of study. on the subject is planned there for next year. Papers included studies on the Gold-Palladium Alloys diffusion coeficient of hydrogen in Professor Ted B. Flanagan of the Univer- gold-palladium alloys, the Variation of sity of Vermont presented measurements of electrical resistance with hydrogen con- diffusion coefficient of hydrogen as a function tent of palladium at low temperatures, of hydrogen content in a series of gold- and the absorption by palladium alloys palladium alloys containing from 19 to 56 atom of hydrogen at extremely high pressures. per cent gold. Good agreement was found The symposium also dealt with hydro- between results obtained by two indcpendcnt gen absorption by nickel alloys. Some techniques. A marked variation of the Fick diffusion coefficient as a function of hydrogen of these papers parallel work on pallad- content was obtained for alloys where the ium and are also briejly reported here. hydrogen content couId be varied over a sufficiently widc range For this to be discerned. The value of the diffusion coefficient at A symposium concerning the absorption of vanishingly small hydrogen contents was hydrogen by palladium and palladium alloys, virtually unchanged as a function of alloy and by nickel and nickel alloys, was organised composition from pure palladium up to in July by Professor B. Baranowski at the 20 per cent gold, and then declined rapidly as Institute of Physical Chemistry of the Polish a function of the percentage of gold in the Academy of Sciences in Warsaw. alloys. In a general introductory review of transition metal-hydrogen systems, Dr F. A. Low Temperature Studies Lewis of Queen’s University Belfast discussed Dr T. Skoskiewicz of the Polish Academy the possibilities of overall correlations be- of Sciences, Warsaw discussed the changes tween the various groups of solid hydrides of with variation of hydrogen content of the the periodic classification. In particular, anomalous variation of the electrical re- attention was drawn to similarities between sistance of hydrided palladium with temper- certain features of the palladium-hydrogen ature in the vicinity of the related specific system and hydrides of transition metals of heat anomaly occurring at around 60 K. It sub-groups 3,4 and 5, such as non-stoichiom- was advanced that the behaviour could be etry of solid phases and existence of critical accounted for in terms of transitions between phenomena, metallic properties and ap- two forms of palladium hydride possessing

Platinum Metals Rev., 1970, 14, (4), 131-132 131 the same Debye temperature and exhibiting silver alloys containing up to 70 per cent virtually parallel relationships between elec- silver were still capable of absorbing signifi- trical resistance and temperature. A com- cant contents of hydrogen at the highest parison was made of the heat of transformation pressures employed. Certain features of the obtained by integration of the specific heat results indicated some possibility of using the data and the heat of transformation calculated changes of electrical resistance for estimating from the temperature dependence of the hydrogen contents and fugacities in the higher concentration of the low temperature modifi- ranges of pressure. cation-as estimated from the measured electrical resistance by considerations of' the Nickel Alloys Nordheim rule. It was concluded that the Dr H. J. Bauer of the University of Munich low temperature form consists of entities of reported on the effects of absorption of four hydrogens. hydrogen on the electrical and magnetic properties of nickel and nickel-copper alloys. High Pressure Studies Quantitative differences in the changes of Recent extensive study by Professor magnetisation due to hydrogen and deuterium Baranowski's group in Warsaw of the during absorption of the respective isotopes absorption of hydrogen by palladium and its indicated that deuterium had a higher alloys under high pressures of the gas was mobility than hydrogen in the nickel-copper reflected in lectures by Professor B. alloys-in general parallel with comparisons Baranowski and A. W. Szafranski of the of the diffusibility of hydrogen and deuterium Polish Academy of Sciences. Information in palladium and palladium alloys. Problems concerning the techniques employed in of making measurements of magnetic sus- measurements of changes of electrical resist- ceptibility and electrical resistance of nickel ance at pressures of hydrogen up to 25,000 hydrides at temperatures below 20 K were atmospheres was presented in both lectures. discussed, and evidence was presented that Professor Baranowski specifically dealt with some behaviour patterns of these parameters the palladium-platinum-hydrogen system at at low temperatures had their origins in the 25°C and presented results showing that a Kondo effect arising from the presence of maximum in the relationship between elec- transition metal impurities in the nickel trical resistance and hydrogen content known matrix. for the palladium-hydrogen system continued Dr G. Wolf of the Bergakademie, Freiberg, to be present in analogous relationships for East Germany, presented results of specific palladium-platinum alloys containing up to at heat measurements on samples of nickel least 40 per cent platinum. Generally also it hydride over the temperature range 10 to was either shown or indicated that the 200 K. resistance afterwards decreased to a value A. Stroka of the Polish Academy of close to that of the hydrogen-free metal. Sciences, Warsaw presented a survey of Evidence also suggested that for alloys differences of the thermodynamic para- containing >70 per cent platinum the meters relating to the absorption and de- solubility of hydrogen seemed likely to have sorption of hydrogen and deuterium to and decreased to very low values. from nickel hydrides and deuterides as Szafranski's studies indicated the possibility derived from measurements obtained by high of substantial further extension of the complex pressure techniques. variety of forms of the relationship between It is hoped that a more extended conference electrical resistance and hydrogen content for concerning this general field of study will the silver-palladium series of alloys. Measured take place at Wroclaw, Poland in 1971. changes of electrical resistance suggested that F. A. L.

Platinum Metals Rev., 1970, 14, (4) 132 Platinum-Carbon Catalysts with Molecular Sieve Properties

SHAPE SELECTIVITY IN HYDROGENATION CATALYSIS

By B. J. Cooper Research Laboratories, Johnson Matthey & Co Limited

Applications of molecular sieve materials have become of increasing interest in catalysis. The ability of these materials to diferentiate on the basis of molecular size gives them a unique form of selective catalytic action uith the additional berrejit of high resistance to sorption of large poison molecules. Hitherto their major application has been realised with zeolites but new platinum catalysts possessing similar properties and based on a carbonaceous structure have now been developed in the Johnson Matthey Research Laboratories.

Over the past few decades increasing inter- streams, the purification of hydrocarbon est has been aroused in the field of adsorp- solvents, and the separation of hydrocarbon tion, and to a lesser extent catalysis, by mixtures. Such compounds also have the materials which, as a result of their structure, advantage that pore size may be tailored by are capable of selectively differentiating altering the chemical composition of the between molecules of differing size. These zeolites, thereby altering the molecular sieve materials, often described as molecular characteristics of the solid (2). sieves, contain an internal volume of pores Another class of compounds which may whose width is commensurate with the cross- show the existence of molecular sieve pro- sectional diameter of such molecules as perties are the amorphous carbons, and nitrogen, carbon dioxide, and the normal recently interest in certain of these carbons hydrocarbons, whereas branched hydro- has been revived by molecular sieve tech- carbons with tri- and tetra-alkyl substitution nology. Early evidence for the existence of are too large to enable access to the internal molecular sieve properties in microporous pore structure to occur. Selective adsorption carbons was prescnted by Franklin (3) who therefore results from steric hindrance to reported that the apparcnt density of carbons diffusion through the porous medium and is during graphitisation depended on the fluid distinct from selective adsorption as a result immersion medium, larger molecules giving of a specific chemical reaction. lower densities duc to incomplete penetration The major application to date of molecular of the pore structure. Bond and Spencer (4) sieves has been realised with the application have also deduced that a significant pro- of zeolites (crystalline alumino-silicates) to portion of the surface area of coals was such problems as gas and solvent purification associated with pores of diameter less than (I). The inherent ability of zeolites to adsorb 5 to XB. selectively molecules entering the pore Recent developments in this field have structure renders them ideal for removing shown that a great number of coals, cokes and such impurities as water from damp gas notably organic polymer chars are molecular

Platinum Metals Rev., 1970, 14, (4), 133-139 133 sieves. Unfortunately a major disadvantage of Thus it is clear that when the active site is organic chars is the low adsorptive capacity deposited within a porous structure, steps (i) which reduces their economic importance in and (iii) are of considerable importance as relation to zeolites. This difficulty was over- the reactants and products may have to come by the development of a composite negotiate long and tortuous paths to the carbon molecular sieve (5) which consists of a active centre. non-selective, high area activated charcoal The transport of material through porous coated with charred thermosetting polymer. structures is dependent on pore size, and as A significant difference between the zeolites pore size decreases a point may be reached and carbon molecular sieves (CMS) has been where the rate of diffusion of reactants or demonstrated by molecular probe adsorption products is slower than that of catalytic studies (5). Thus by adsorbing both cylind- reaction, and the reaction becomes diffusion rical and planar molecules of varying size, controlled (9). This condition is generally the zeolites were demonstrated to possess avoided by careful design of the catalyst as it cylindrical pore mouths in accord with their represents an inefficient use of expensive crystalline structure, whereas CMS possessed metal not only in terms of decreased activity slit pore geometry probably resulting from the per unit weight of metal, but decreased formation of micro-fissures between turbo- selectivity also. At extremely small pore stratic graphitic platelets in the carbon (6). sizes the reactant may be totally prevented from entering the pore system because the Molecular Sieves in Catalysis molecular size of the reactant is larger than Porous solids have long been employed as the pore entrance. Conversely, smaller mole- a means of efficiently distributing expensive cules will continue to diffuse into and out of catalytic constituents such as platinum and the pore system. If a catalytic site is present other precious metals. By such means the within such a pore system a unique form of surface volume ratio of the catalytic metal catalytic selectivity will be obtained where the may be maximised to ensure the fullest molecular sieve effect of the support dictates possible use of the metal in the catalytic the size of molecule which reacts. reaction. Several other important advantages Molecular sieve catalysts have been realised are often claimed for supported catalysts such in practise by the use of zeolites which are as the inherent chemical superiority of the both catalysts in their own righs (IO), and support-catalyst complex (7), and the dual also used as supports for active material role of both catalyst and ‘support’ that is (11, 12). Such catalysts arc highly selective obtained, for example, using platinum on in both cracking reactions and hydrogenation acidic alumina for petroleum reforming (8). reactions, selective cracking of n-paraffins in a On the other hand, the use of a porous mixture of n- and iso-paraffins occurring over support to distribute catalytic metal is not the zeolite alone, and selective hydrogenation without its disadvantages. Not only can the of n-alkenes in the presence of branched chemical composition of the support influence alkenes occurring over a platinum-impreg- the performance of the catalyst but its nated zeolite. The latter catalyst also showed physical structure also. The various stages in high resistance to large poison molecules (12) a catalytic reaction at a solid surface are such as thiophen, purcly as a result of the considered to be as follows : molecular sieve structure dictating the size (i) diffusion of reactants to the active site; of molecule capable of reaching active sites. (ii) adsorption on to the catalyst, reaction and desorption of products; Carbon Molecular Sieve Catalysts (iii) diffusion of products away from the Until quite recently (13) no reports have catalyst. appeared in the literature of the use of carbon

Platinum Metals Rev., 1970, 14, (4) 134 molecular sieves as catalyst supports, al- groups available for the attachment of metal though innumerable advantages of carbon- salts a high proportion would exist on external aceous materials are claimed in comparison surface. Obviously, catalytic stereo-selectivity to zeolites (14). Of these the main claims are due to the molecular filter action of the sup- the cheapness of preparation, the thermal port would be lost if metal is deposited on stability, and their resistance to attack by surface, external to micropores. strong acid or alkali. Work in the Johnson Matthey Research Perhaps the lack of interest shown has been Laboratories has led to several novel methods as a result of the difficulty of impregnating of preparation of carbon molecular sieve carbon molecular sieves with active catalyst catalysts. The aim of the work has been to and subsequently maintaining selectivity. In disperse an active catalytic metal (e.g. the zeolitic system impregnation is relatively platinum) throughout a molecular sieve easy and consists simply of ion-exchanging framework such that the metal is embedded the zeolitic cation for that of the catalytic within the microporous structure of the sieve. metal, salt, followed by reduction. As a Under these conditions the ability of reactant result the cations are situated at the centre molecules to diffuse through the molecular of the “cage-like” crystal structure and thus sieve automatically selects the size of reacting the catalyst material is embedded within the molecule. As conventional methods of pre- molecular sieve framework. Carbon mole- paration such as impregnation of charcoal cular sieves, however, are highly amorphous, with a metal salt from solution are unsuitable, and although there are probably functional the reverse procedure has been adopted

Table I The Hydrogenation of Linear and of Branched Olefins over Conventional Platinum/Ch@rcoaland oyer PIatinum/Carbon Molecular Sieves

A 1.78~ moles/pulse at 25°C. Reciprocal B 2.00 x moles/pulse at 30°C. Reciprocal space velocity 9.0 x g.min/cm3 space veloc ’ 4.0 x lo-* g.min/crn3

Olefin 4lkane produced (mole ~10~) Olefin Ukane produced (mole x lo4)

Pt/CM$ I 1oyo Pt/C Pt/CMS 2 2% Pt/C

a propylene 0.165 1.49 b butene-I 0.22 1.77

b butene-I 0.06 1.28 c isobutene 0.02 1.14

c isobutene 0 1.32 e 3,3-dimethyl- 0.02 0.99 bu tene-I 4 3-methylbutene-I 0 I.25

b jelectivity a 1 .o 0.53 Selectivity - 0.92 0.61 al-c b+c b b ielectivity - 1 .o 0.51 Selectivity - 0.92 0.64 b+d b -te

a propylene; b butene-I : c isobutene; d 3-methyl-butene-l ; e 3,3-dimethyl-butene-I C C C c-c=cC c-c-c=c C I I c- cI -c-. c c-c-cC c-c-c=c C I C

Platinum Metals Rev., 1970, 14, (4) 135 Fig. 1 Pores of n Pt/CMS catalyst ( x 6400). Large pore diameter approx. 3p. Small pore diameter approx. 0.5~. (Courtesy of Mr A. E. B. Presland, Imperial College, Dept of Chemical Engineering 6;. Chemical Technology)

whereby the carbonaceous structure is de- internal pore structure. Thus a typical veloped around a platinum dispersion in material was found to adsorb nitrogen and solution. In essence the process involves the butane, but not isobutane and neopentane, polymerisation of an alcoholic medium the adsorptive capacity towards the former containing a colloidal suspension of platinum. gases (expressed for convenience in terms of A thermosetting resin is obtained which is surface area) being IOO m2/g and 20 m2/g. carbonised under oxygen-free nitrogen to Scanning electron microscopy (see Figure I) form the platinum/CMS catalyst (Pt/CMS I was only capable of detecting extremely large in Table I). A second method has also proved pores 0.5 to 3 microns diameter, the rest of highly satisfactory, and is in fact a variation the material appearing quite homogeneous. on the composite carbon molecular sieve No surface platinum was detected by this preparation (5). In this case a conventional method. platinum/charcoal catalyst is coated with thermosetting polymer and carbonised, with Catalytic Selectivity the result that a molecular sieve skin is The catalysts were tested for hydrogenation formed over the original catalyst (Pt/CMS 2 activity using linear and branched mono- in Table I). This type of preparation has the olefins as reactants. The oleiins chosen were obvious advantage that it may be extended propylene, butene-I, isobutene, 3-methyl- to any form of solid catalyst. butene-I, and 3,3-dimethylbutene-1. These Studies (13) have shown these materials to were chosen to show how catalytic behaviour be highly selective adsorbents capable of varies with their molecular structure. As can differentiating between linear and branched be seen from the carbon skeletons in Table I, hydrocarbons, with the result that only linear the effective molecular diameter increases as molecules are capable of penetrating to the more branching occurs.

Platinum Metals Rev., 1970, 14, (4) 136 The reaction was studied using a pulse shap, ,Ciective. It is interesting to note that flow micro-reactor attached to a gas chromato- whereas the conventional catalyst displays a graphic analyser. A study of the elution of small degree of selectivity that may be asso- reaction products from the hydrogenation of ciated with decreasing activity with increasing propylene using the pulsed flow technique methyl substitution about the olefinic double rapidly established the slow diffusion of bond, the high selectivity of the molecular reaction product from the catalyst. It can be sieve catalyst is almost certainly associated seen (Fig. 2) that the propane concentration with limitation of access to active sites by continues to increase long after the propylene molecular size. concentration reaches a maximum (i.e. when Certain preparations of platinum-contain- the reactant pulse has passed the catalyst). ing CMS catalysts, however, showed lower Such an effect is almost certainly associated selectivity than others (Table 11). This was with the slow diffusion of product from the found to be associated with the presence of molecular sieve support. surface metal as demonstrated by the results The stereoselectivity of the catalysts for on the uncarbonised polymer which has no mono-olefin hydrogenation is shown in pore structure. Two methods of inducing Table I where selectivity is expressed as : high selectivity on these catalysts have been linear olefin produced developed based on a form of selective linear olefin -tbranched olefin produced poisoning. The first method consists simply Thus selectivity may vary from 1.0, where of recoating the catalyst with another layer of only linear olefin reacts, to 0.5 where both molecular sieve. The second method con- linear and branched olefins react at equal sists of poisoning the metal accessible to rates. From a comparison of molecular sieve larger molecules using a poison of similar catalysts with conventional Johnson Matthey size. Both methods are successful in inducing platinum on charcoal catalysts it is apparent high selectivity (Table 11). To reduce the that the molecular sieve catalysts are highly hydrogenation of 3+dimethylbutene- I the

Platinum Metals Rev., 1970, 14, (4) 137 Table II The Selectiyity of Poisoned Pt CMS Catalysts in Mono-olefin Hydrogenation

A Poisoning by recoating with carbon molecular sieve. The hydrogenation of (a) propylene and of (6) isobutene at 150°C. 2.00~10 moles!puIse. Reciprocal space velocity 0.040 g.min. cc.-l

Catalyst Propane produced lsobutane produced Selectivity (molex lo4) (molex lo4)

Uncoated polymer 1.35 0.37 0.78 Uncoated catalyst 1.30 0.52 0.71 Coated polymer 0.1 7 0.09 0.65 Coated catalyst 0.45 0.02 0.96

B Poisoning by injection of 1.5~10-V. 2-methyl-2-propane thiol. The hydrogenation of propylene and of 3,3-dirnethyl-butene-I at 150'C. 2.00r,lo-% moles/pulse. Reciprocal space velocity, 0.021 g.rnin.cc

Catalyst Propane produced 2,2-d i methyl butane Selectivity (molex104) produced (mole x lo4)

Before poisoning 2.00 1.50 0.57 After poisoning 1.76 0.02 0.99 catalyst was poisoned with a-methyl-2- injecting ethane thiol, CH,CH,SH, (Fig. 3b) propane thiol, (CH,),CSH, (Pig. 3a) the the propylene activity rapidly decayed be- activity towards propylene hydrogenation cause the smaller poison molecule was capable remaining virtually unchanged. However, on of reaching the active sites for propylcne

Platinum Metals Rev., 1970, 14, (4) 138 hydrogenation existing within the molecular References sieve structure. Both poisoning curves are I “Union Carbide Molecular Sieves for Selec- tive Adsorption”, British Drug Houses Ltd, typical of those found with pore mouth Poole, England poisoning (IS), but are unique in demon- 2 R. M. Barrer, Nature, 1955, 176, 1188 strating the high resistance of the catalyst to 3 R. E. Franklin, Trans. Faraday SOC.,1949, large poison molecules. 45,668 4 R. L. Bond and D. H. T. Spencer, “Industrial These novel Johnson Matthey catalysts, Carbon and Graphite”, SOC. Chem. Ind, therefore, are both highly selective in their 1958,231 catalytic action and highly resistant to large 5 P. L. Walker, T. G. Lamond and J. E. Metcalfe, 2nd Int. Carbon & Graphite Con- poison molecules. They would therefore ference (S.C.I.), London, 1965 appear to be comparable to zeolitic systems, 6 W. F. Wolf€,J. Phys. Chem., 1958, 62, 829 which are finding a growing number of 7 A. C. C. Tseung and B. S. Hobbs, Platinum Metals Rev., 1969, 13, (4), 146 commercial applications. They do possess 8 V. Haensel and H. S. Bloch, Platinum MetaZs several advantages over zeolites both in the Rev., 1964, 8, z inherent advantages of the use of a carbon- 9 A. Wheeler, Advances in Catalysis, 1g51,3,250 10 P. B. Weisz, V. J. Frillette, R. W. Maatman aceous support outlined previously, and also and E. B. Mower, J. Catalysis, 1962, I, 307 they are easily adapted for use as a composite 11 J. A. Rabo, I?. E. Pickert, D. N. Stamires and catalyst any solid catalytic material. J. E. Boyle, Actes du Deuxieme Congris with Internationale de Catalyse, 1960,2,2055. They also offer several interesting possibili- 12 J. A. Rabo, V. Shoemaker and P. E. Pickert, ties in that the composite preparation offers 3rd. Int. Congress on Catalysis, 1964~2,1264 13 B. J. Cooper and D. L. Trimm, paper to be a potential method for more precise control presented at the 3rd Int. Carbon & Graphite of the commerciaI activated carbons com- Conference (S.C.I.), London, 1970 monly used as catalyst supports. 14 D. H. T. Spencer, “Porous Carbon Solids”, Ed. R. L. Bond, Academic Press, London and Grateful acknowledgement is made to New York, 1967, 87 Dr D. L. Trimm, of Imperial College, for his 15 P. G. Ashmore, “Catalysis and Inhibition of Chemical Reactions”, Butterworths, London, advice and encouragement during this work. 1963, I90

Platinum Metal Coatings for Stereoscan Specimens

The Stereoscan electron microprobe system produced by Cambridge In- struments Limited eliminates much time-consuming specimen preparation work associated with, for example, transmission electron microscopy. Specimen preparation generally involves only drying, fixing on to the specimen stub and rendering the specimen conductive by evaporating a metal layer, e.g. 300 to 500 A gold- palladium alloy, on to it to prevent charge formation without masking the surface detail andimpairing resolution. Workers at the London School of Hygiene and Tropical Medicine, under the direction of Professor A. W. Woodruff, have now used rhodium vapour in this way to obtain excellent Stereoscan pictures of the surface of Toxocara canis larvae, which occur in the intestines of dogs. Larvae which arise in man from the eggs of Toxocara canis burrow into the human intestine wall and are carried by the bloodstream to organs such as the eye, where damage may occur. They also predispose man to virus infections such as poliomyelitis.

Platinum Metals Rev., 1970, 14, (4) 139 The History of Matthey Bishop By Donald McDonald Johnson Matthey & Co Limited

The completion of its new refinery and continuous current of air or other gases from chemical complex marks the latest stage in two storage vessels under hydrostatic pres- the development of the first establishment in sure. This enabled hydrogen and oxygen America for the refining and fabrication to be used and therefore much higher of platinum, originally set up by Joaquim temperatures were obtainable than had been Bishop in 1842. Before that, all pure and possible before, and it became practicable fabricated platinum was imported from to melt a number of substances which had Europe and distributed by agents of the hitherto been regarded as infusible. Among English and French refining houses. In the these was platinum and in due course a main, the business concerned crucibles and melted ingot of 28 ounces was produced. similar laboratory ware, wires and foils, but In this work Hare was assisted by Joaquim as a growing demand for sulphuric acid Bishop, the son of English parents tem- emerged, enquiries arose for boilers for its porarily domiciled m Oporto, Portugal, concentration and these were met. But at where he was born in 1806. The French that time no serious scientific work seems to wars disturbed the I'amily and in 1810 they have been undertaken anywhere which might emigrated to the United States, settling have led to the setting up of refining, although, more or less by accident, important experiments were carried out on the melting of the metal. These were made by Robert Hare (1781--1859)~commencing in 1801, in which year he presented a paper to the Chemical Society of Philadelphia on an improvement on the ordinary air blowpipe. In this he was able to feed his burner with a

Joaquim Bishop 1806-1886 The founder of the company, Bishop was for some years employed as instrument maker to Dr Robert Hare at the University of Pennsylvania. In 1842 he set up in Philadelphia the$rst American establishment for melting and fabricating platinum, putting to commercial use Hare's discovery of the oxy-hydrogen torch

Platinum Metals Rev., 1970, 14, (4), 140-146 140 The recent opening of this neiu rpjinery and chemical plant in Winslow, New Jersey. provides Mutthey Bishop uiith increased facilities for the production of the plutincm metals and their compounds and for the recovery of spent catalysts and other materials containing these metals first in Baltimore and finally in Philadelphia. is generally regarded as the foundation of the In 1826 the boy apprenticed himself in the business that became J. Bishop & Co jewellery trade but left this to become a Platinum Works. Already in 1845 he was finisher in a brass foundry. These experiences awarded a silver medal by the Franklin with the working of metals were supported Institute of Pennsylvania for “skill and by some reading in the sciences so that, in ingenuity in the manufacture of platinum 1832, he was able to secure the position of scientific instruments”. It is unlikely, at this instrument maker in the University of stage in his career, that he did any refining, Pennsylvania and assistant to Hare. As such although we know that he did study the he must have taken part in the latter’s subject and make himself familiar with the important electrical and electrochemical work, work of Cloud, Wollaston and Tennant, including of course the blowpipe. He also all of which was available in the U.S.A. as did some outside business, because there is an early as 1809. His own operations probably entry in The Philadelphia Directory for never went further than the cleaning and 1836 of “J. Bishop, manufacturer of separating of scrap, and reliance on getting machines”. Then, in 1839, he left the platinum sponge and sheet of fair quality University, it is said at Hare’s suggestion, from the agents of the English and French to become a “Machinist and Philosophical refiners. Instrument Maker” and opened premises in In 1858 he moved out of town to Radnor Philadelphia. and again, in 1865, to Sugartown, where he His work on platinum began in 1842, bought an estate of 43 acres, remodelled the when he was urged by his friends to take it house and built a workshop. There he set up, using the blowpipe in the process, and this up one larger and two smaller rolls, a draw

Platinum Metals Rev., 1970, 14, (4) 141 Joaquim Bishop’s business card dating from 1839 when he lefl the University of Pennsyl- vania to set up as an instrument maker in Philadelphia. Three years later he began his work on platinum

bench, a smith’s shop for forging, and a that George Matthey was credited in England melting room with receivers for producing with the invention of this technique “which hydrogen and oxygen. The metal was melted I have been performing for the last 20 years in 20-ounce ingots and small laboratory or more”. apparatus was produced from them, there In 1876 he was awarded a bronze medal being no evidence of larger-scale work. for an exhibit of platinum at the Philadelphia The quality and workmanship was said by Centennial Exhibition and he continued to users to be excellent and “from the beginning be active in the business until about two its several steps were crowned with remark- years before his death in 1886. His assistant, able success”. The staff was only two or three and later partner, Edwin Cox, carried on the in number and Bishop was his own craftsman, work until 1889 when Bishop’s grandson salesman and traveller. A description exists and heir, J. B. Matlack, came of age. In of how, at the age of 67, he would come to January 1903 the workshop and refinery, town with the week’s product of crucibles in with all their records, were completely a market basket slung over his arm and destroyed by fire. But the business con- dispose of them to his various customers, tinued, with Matlack as President and while taking orders for the next week. He Charles H. Kerk, who had come in on Cox’s seems at an early stage to have replaced the death on purchase of his interest and became joining of platinum by gold-soldering by Secretary and Treasurer. A new works was inventing the process of fusion-welding and built and powered with electricity and steam, to have been very surprised when told in 1880 and in 1909 the Company was definitely

The silver medal awarded to Bishop in 1845 by the Franklin Tnstituteof Penn- sylvania for his work in the fabrication of platinum

Platinum Metals Rev., 1970, 14, (4) 142 The second plant established by Bishop in 1865 at Sugartown, Chester County, I’ennsyl- vania, with the founder (left) and his small staf. The plant included a melting shop with means for producing hydrogen and oxygen, a forge, one large and two small rolling mills, a draw bench and a chemical laboratory incorporated as J. Bishop & Co Platinum the business of Croselmire in 1901and that Works. of Baker in 1903 on behalf of the Syndicate; Rut in the meantime, conditions in the so, from then onwards, the Bishop business platinum business in the U.S.A. were was confronted by an energetic and well- beginning to change. In 1875 a small supplied competitor, and must have become competitor with Bishop, named Daniel W. dependent on its old scientific friends in and Baker, started at Newark, New Jersey, around Philadelphia. That it was able to first as a manufacturing jeweller and later build and equip its new works in 1903 at taking up the fabricating of platinum. By Malvern shows that it still had some con- the early 1890s he was issuing a proper siderable support and it appears that Matlack catalogue of crucibles, and a little later and Kerk were able to keep it going against another small business was started, also in ever increasing competition. The European Newark, by Charles W. Croselmire who participation in the Baker business ended sold platinum in wire and sheet. But the after the 1914-18 war and Engelhard took largest changes followed the arrival in the over full charge of it and was able to secure U.S.A. in 1891 of Charles Engelhard as adequate supplies of platinum originating agent of the European firm of Heraeus, and in the American continents from the workings he, in 1894, was appointed American rep- of the International Nickel Company and the resentative of the newly-formed European revived production of Colombia. Life at Syndicate for the Protection of the Platinum Malvern cannot have been easy, and indeed Industry, sponsored by the three European there is evidence of real and mounting refining houses. Engelhard immediately difficulties in the later 1920s. embarked on a policy of expansion, acquiring At this stage Johnson Matthey began to

Platinum Metals Rev., 1970, 14, (4) 143 take an interest in the idea of allying them- to spare to send there. Bishop’s American selves with Bishop in order to help their competitors, on the other hand, had all the New York office to become a more effective metal they needed. The Company lost money outlet for the platinum which would one day for the next few years bur Mr A. B. be available to them. In I927 they purchased Coussmaker, after 1933 the Director res- a small interest in the Bishop company and ponsible for Johnson Matthey’s interests in gave them an agency for sales in the United North America, declared that, despite the States. In 1931 this was followed by a more depression in the U.S.A., and the lossea comprehensive arrangement. At that time Johnson Matthey must stay in the business J. B. Matlack retired and C. H. Kerk became because they could not afford to be squeezed President, while his son Paul Kerk, who had out of the North American continent. been an employee since 1922, was made In these circumstances, conditions for the a Vice-president. Two years later the elder management and staff must have been very Kerk retired and the younger succeeded him discouraging, but they seem never to have as President; in the meantime Johnson lost hope and there is much evidence of Matthey had purchased the holdings of inventive and creative work under the Matlack and Charles Kerk and so acquired enthusiastic leadership of Paul Kerk. In control of the Company. 1914 they had taken up the manufacture of In 1931 business conditions in the U.S.A. spinnerets for the spinning of what was then were in a state of slump and, in addition, called artificial silk (rayon). These were then Johnson Matthey had little or no platinum made from hardened platinum and had to be

In 1934 a new American source of the platinum metuls was established when dredging operations began at Goodnezus Bay in Alaska. From the beginning the refining and marketing of the output has been undertaken by Bishop

Platinum Metals Rev., 1970, 14, (4) 144 Today the rejining and fabricating activities of Mutthey Bishop are barked by the immense resources of Rustenburg Platinum Mines of South Africa. Production of platinum alone is scheduled to reach 1,VVO,VOV ounces a year hy 1971 and to rise to 1,200,VOV ounces by the end of 1972. Total reserves of platinum have been estimated at over 2OO,UOO,OVU ounces pierced with large numbers of small holes with new and significant development took place no burrs. on the platinum side. This arose out of the At about that time too they were making discovery in 1934 of valuable deposits of fine capillary tubing, also of hardened native platinum at Goodnews Bay, Alaska, platinum and platinum-gold alloy, used for the output of which had by 1938 reached hypodermic needles. In 1928 a British 38,000 ounces a year. From the beginning competitor appeared for these needles made Johnson Matthey secured the refining and of stainless steel and Bishop rose to this marketing of this against very strong American challenge very keenly. By I931 they were competition. Bishop were of course quite making satisfactory tubing in this material unable to tackle the refining of such a in growing quantities, the first producer of it quantity, and it all had to be shipped to in the United States. In 1934 they went into London for that purpose. From Lhe start, the manufacture of the hypodermic needles Coussmaker saw that sooner or later Bishop themselves, and by 1935 they were turning would have to be equipped with a refinery out 19 million a year of “the best needles in large enough to deal with this indigenous the U.S.A.”. In 1938 the plant had to be American product. Eventually the blockade enlarged but unfortunately the market was by of England after the outbreak of their war no means freely open and Bishop reaped little in 1939 forced the issue and with the help benefit financially until the 1941-45 war of the British Government the refinery was came to open the floodgates of demand. built and put into action in 1940. This But the tubes had played an essential ensured that the Goodnews Bay metal was part in keeping the business going until a kept in the family during the war and after.

Platinum Metals Rev., 1970, 14, (4) 145 Vincent W. Makin President of Matthey Bishop since 1964 and a Director of Johnson Mattltey

in an up-to-date and enterprising business. In 1964 Vincent W. Makin joined Bishop as President, bring- ing with him a deep understanding of the precious metals industry. Unconstrained by involvement in the company’s long traditions, he none the less adapted them to his own concepts of progress and created an atmosphere in which Under war conditions the needle business the innate energies of his team were put to flourished and expanded into the making of maximum advantage. the glass parts of the syringes as well. This The Company celebrated 125 years of continued until the end of the Korean war operation in 1967 and changed its name to in 1953, but by then another new develop- Matthey Bishop Inc to underline the close ment on the platinum side had made its working relationship with the U.K. operations appearance when the petroleum industry set of the Group. For some time it had been about up-grading its products into high apparent that continued success in the tube octane gasoline by means of re-forming on a business would require a concentration of platinum catalyst, from which the platinum effort and capital resources that could not be had to be recovered after use. The space spared from the ever increasing demands previously devoted to needle production was made by Matthey Bishop’s growing status hurriedly converted to this purpose. This in the expanding field of the platinum metals. work was related to a great deal of research It was with great regret that the tube business on the catalytic properties of platinum and a was disposed of in 1969 as part of the strategy strong lead was given in this direction to to optimise the Company’s opportunities in the other and older parts of the Johnson Matthey platinum business. organisation. Meanwhile the Tube Depart- The year 1970 is one in which the new ments, after drastic reductions in 1956, chemical and refining complex will begin to continued to flourish in new and modernised play its part in still further developing plants set up in 1959 to 1960, while the Matthey Bishop’s important role in the platinum sections, now well supplied with platinum field, while a new centre for melting raw material from the increasing output of and fabricating has also just been completed Rustenburg Platinum Mines and Johnson on the outskirts of Malvern, the headquarters Matthey, played a full and important part of the Company from its very early days.

Platinum Metals Rev., 1970, 14, (4) 146 ABSTRACTS of current literature on the platinum metals and their alloys

PROPERTIES Pt-Ni alloys were measured at 1.2-4.2 K. Specific heat results fitted C=yT T,f3’T3 and resistivity Effect of Grain Size on the Creep of Platinum- fitted pypo kATz, Experimental results are used Rhodium Alloys to evaluate current theories of localised spin I. I. NOVIKOV, F. S. NOVIK, E. I. RYTVIN, S. S. fluctuation effects. PRAPOR and I. F. PRUZHININ, Izv. Vysshikh Ucheb. Zaved., Tsoet, Metall., 1970, (3), 110-113 On the Structure of the Platinum-Copper- Models are described for estimation of the rate of Zinc Composition creep of 7-10:/~ Rh-Pt alloys at 1300“C, applied Y. KHAN, B. v. R. MURTY and K. SCHUBERT, J. pressure 1.0-1.3 kg/mm2and grain sizes from 0.4 Less-common Metals, 1970, 21, (3), 293-303 to 2.8 mm. Structural analysis of the Pt-Zn-Cu system showed its brass-like properties. Both the Deviations from Matthiessen’s Rule in valence-electron and the core-electron spatial Dilute Gold and Platinum Alloys correlations affect the alloy structure. R. G. STEWART and R. P. HUEBENER, Phys. Rev. B, 1970, IJ(81, 3323-3338 Field-electron Microscope Study of Pt-Ba Positive deviations 4(T) from Matthiessen’s rule Alloy have been observed in several dilute Au and Pt YU. v. ZUBENKO and N. P. ESAULOv, Fiz. Tverd. alloys (solute concentration z 0.1-5 at. ”). A(T) Tek 1970, 12, O), 852-855 a log T for Au-Co and Pt-Rh at 30-200 K. A(T) An emission image of the surface of single has a sharp peak at 30-50 K for the low solute crystals of 1.3 wt.o/, Ba-Pt was obtained. The concentrations. Results are interpreted in terms of formation of an adsorbed Ba film on the alloy the two-band model, the anisotropy of the electron surface was studied visually during thermal scattering, and the shift in the Fermi surface due treatment. to alloying. The X-ray Structural Investigation of Pt-Ba Vacancy Formation and the Thermal Ex- and Pd-Ba Alloys in the Region of the pansion of Platinum Compositions Pt,Ba and PdjBa J. VAN DEN SYPE, ScTipta Metall., 1970, 4, (4), N. N. ZHURAVLEV, N. P. ESAULOV and I. v. RALL’, 251-254 Kktallografya, 1970, 15, (z), 374-376 The measurement of the coefficient of thermal Pd,Ba and Pt,Ba are isomorphous with CaCu,- expansion of Pt at 1000-1900 K is discussed. type structure. X-ray studies of Pt,Ba variously Measurement by optical comparison and by a heat-treated show that it is stable over a wide direct method agree well at 1000-1400 K. Above range of temperature, whereas Heumann claimed 1400 K increasing deviation is in evidence, that it was stable only at high temperatures. amounting to 264/0 at 1900 K. The deviation is explained on the basis of a vacancy relaxation Hydrogen Solubility in Electrolytically De- effect inherent in the temperature technique for posited Thin Films of Palladium measuring thermal expansion. R. V. BUCUR and L. STOICOVICI, J. Electroanal. Chem. Interfac. Electvochem., 1970, 25, (2), 342- Internal Friction in the Equiatomic Alloy 343 Copt The quantity of H, absorbed in electrodeposited w. CHOMKA, J. BELSON, P. EITIN and J. PAULEV~, thin films of Pd in equilibrium at atm. pressure C. R., Shr. C, 1970,270, (24), 2042-2044 was determined in 0.1 M €€,PO, solution at Internal friction observed in Copt during an- 25°C. For a compact Pd or Pd black film the H, nealing is very sensitive to changes caused by solubility r is 0.5645 0.003; r is less for bright magnetoelastic effects, which are affected by the films and is very sensitive to heating. Use of a induced magnetism and by the degree of ordering Pt anode in the electrodeposition of bright films of CoPt. results in an increase in H, solubility above the reference value. Specific Heat and Electrical Resistivity of Exchange-enhanced Dilute Pt-Ni Alloys Non-linear Magnetisation of Pd c. A. MACKLIET, A. I. SCHINDLER and D. J. F. A. MULLER, R. GERSDORF and L. w. ROELAND, GILLESPIE, Phys. Rev. B, 1970, I, (8), 3283-3290 Phys. Letr. A, 1970, 31.4, (8), 424-425 The specific heat and electrical resistivity of dilute The non-linear magnetisation of Pd at 4.2 K

Platinum Metals Rev., 1970, 14, (4), 147-156 147 was determined in semi-continuous fields up to measured at 1.2-30 K in extcrnal fields of up to 325 kOe. For the expression M=xH(1+j3H2), 30 kOe; field strength greatly influenced the p= T(9.51~.7)x Io-"m2/A2. Measurements excess specific heat. A comparison between Pd were repeated with a Pt sample where ~p=(of3) and Pt alloys emphasised the smaller exchange x Io-Z1m2,1A2compared with (1011.8) x IO-~~ enhancement in Pt. Results for dilute alloys of m2/A2for Pd. Mn in Pd differed greatly from those for Co or Fe in Pd. Elastic Constants of Monocrystalline Alloys of PI-Rh and Pd-Ag between 4.2 The Mechanism of Ordering of Alloys with K and 300 K Periodic Antiphase Domain Structure L. N. BUINOVA, V. I. SYUTKINA, 0. D. SHASHKOV and E. WALKER, J. ORTELLI and M. PETER, Ibid., (9, 240-241 E. S. YAKOVLEVA, Fa. Metal. Metalloved., 1970, 29, (6), 1221-1230 The elastic properties of six monocrystalline Pd-Rh and Pd-Ag alloys were measured. Rcsults Results of electron microscope studies of the are presented graphically and agree with the dislocation structures of deformed Cu-Pd alloys theoretical model predicting a correlation between with regard to the reported ordering mechanism susceptibility and elastic modulus. show that, in alloys with a large number of antiphase domain boundaries, ordering mechanisms connected with the movement of pair dislocations Volumc: and Shape Magnetostriction of have no place. Alloys of Pd-Rh and Pcl-Ag at 4.2 K R. KELLER, J. ORTELLI and M. PETER, Ibid., (7), Low-temperature Specific Heat Study of 376-377 Cu-Pd Alloys Longitudinal and transverse magnetostriction of Y. SATO, J. M. SIVERTSEN and L. I?. TOTH, Phys. Rev. Pd-Rh and Pd-Ag alloys was measured in fields B, I97O,I, (4), 1402-1410 up to 50 kG. Values of the magnetostrictive Variations with composition of the electronic coefficients S, and Sf are presented graphically specific heat y and Debye temperature t)~were and are interpreted in terms of a band model. determined for Cu-Pd alloys from specific heat measurements at 1.5-4.2 K. Deviations from a Optical and Photoemissive Properties of rigid-band model were observed for small Pd Palladium in the Vacuum Ultraviolet concentrations. Thermodynamic properties are Spectral Region discussed in terms of the band structure from y R. c. VEHSE, E. T. ARAKAWA and M. w. WILLIAMS, values. Changes in long and short range order Phys. Reu. B, 1970, I, (2), 517-522 have pronounced effects on y and 8D values. Optical properties of evaporated films of Pd at IO-~ torr were studied at 2-24 eV. Results are Magnetic Properties of Mn and Fe in CuPd correlated with the photoemissive properties of and AgPd similar samples for photon energies of 10.2-22.4 B. DELLBY and H. P. MYERS,~.Appl. Phys., 1970, eV. Interband transitions are identified from the 41, (3), 1010--1011 optical data at 1.3, 3.6, 15.2, and 20.5 eV; at 7.3 The magnetic susceptibility of 0.1-1.0 at.:o Mn and 7.6 eV peaks appear in energy loss functions and of dilute solutions of Fe in CuPd and AgPd -Im[r/(z+~)]and -1in [I is], respectively. was measured. Results were interpreted in terms of s-d exchange scattering of conduction Giant Moments of Dilute Fe in Binary and electrons at the resonance bound d electrons of Ternary Pd Alloys Mn, Fe and Pd. This supports a model for AgPd and CuPd with Pd in resonant bound states for R. r. GUERTIN and s. FONER,J. Appl. Phys., 1970, low Pd concentrations and in energy band 41, (31, 917-918 states for high Pd concentrations. The saturated local moment psat and the ordering temperature T, of very dilute (XIOOO p.p.m.) Effect of Atomic Ordering on the Magnetic Fe in Pd alloys were measured at low temperature. Alloy systems included Pd,-,A,, where Structure of the MnPd, Phase A =Rh, Ag, Pt, or Ni, and Pd,-,,Rh,Ag,. psat E. KREN, G. KADAR and L. PAL, Ibid., 941-942 and the high-field matrix susceptibility XHF were Neutron diffraction and magnetic susceptibility also measured at 1.2-4.2 I< up to 60 kG; psarwas measurements for ordered and disordered MnPd, not simply related to XHF. confirmed an antiferromagnetic configuration for 23-30 at.", Mn. The angle rpc of the magnetic moment to the tetragonal axis was 0" below 25:; Magnetic Field Dependence of the Specific and 90" at higher concentrations. qc was order- Heat of Dilute Pd-Co, Pt-Co and Pd-Mn dependent at 2S'% and increased from o to 90" Alloys with decreasing order. A decrease in the Nee1 B. M.BOERSTOEL and c. VAN B~E,Ibid., 1079-1080 temperature with decreasing order was also The specific heat of Pd-Co-type alloys was observed.

Platinum Metals Rev., 1970, 14, (4) 148 High Temperature Creep of Rhodium On the Composition and Thermodynamics V. I. SHALAEV, I. B. TKACHENKO, V. A. PAVLOV, N. I. of the Uranium-Ruthenium-Carbon System TIMOPEEV and A. V. GUSHCHINA, Fiz. Metal. H. HOLLECK and H. KLEYKAMP, J. Nucl. Muter., Metalloved., 1970, 29, (51, 1601-1068 1970~35, (2), 158-166 Studies of the creep of 99.98% Rh in vacuum at The U-Ru-C phase diagram was established at 63o-177ooC, 0.4-46.2 kg/mm2 showed that the 13oo0C using arc-melted and sintered samples of activation energy Qc of creep is 91 kcalimole, different compositions. The system has two agreeing well with estimates of the activation ternary solid phases: U,RuC, and URu3Cx, energy Q~Dof self-diffusion. It follows from the where x,,,~0.7. Values of the Gibbs free practical agreement in size of Qc and QSD that energy of formation are given, and confirmation of self-diffusion in Rh controls the rate of deform- the reaction UC +~R~+URU,C,+(I-x)C. ation during the steady stage of creep. Activation of the Sintering of Tungsten by Electrical Resistance Measurements on Pd Platinum-group Metals Base Alloys G. V. SAMSONOV, Poroshkovaya Metal., 1970, (I), A. M. SCHIFFRIN, Phys. Status Solidi, 1970, 39, 37-44 (z), K81-K83 Studies of the effect of stable electron con- The effect of the presence of 4f magnetic im- figuration of Rh, Pd, Os, and Ru as activators for purity atoms on the electrical resistivity of Pd sintering of M powder compacts at 1000-2000~C was investigated at 1.4-60 K. A well defined showed that it was due to localisation of non- resistivity minimum exists at -15 K for 8.9 at.0,; localised electrons from the W atoms in the Gd-Pd with a maximum at -5 K. This was nuclei of the Pt-metal atoms, thereby promoting correlated with magnetic ordering in the alloy. mutual dissolution. Activation rose in the order Os, Ru, Rh, and Pd. Magnetic Properties of the Nickel-Rhodium System E. R. KATZ, U.S. Rep PB 287,024, 1969, 159pp CHEMICAL COMPOUNDS Magnetisation and magnetic resonance studies on Activation of Nitrogen by Transition-metal Ni-Rh alloys, which are ferromagnetic for ,63 Complexes at.oi, Ni and paramagnetic for lower Ni con- G. MARTINO and L. SAJUS, Rev. Inst. Fr. Pitrole, centrations, were compared with data of other 1970, 25, (I), 36-45 workers. A model similar to the Anderson model The synthesis and properties of many N- of dilute magnetic alloys explains all the data qualitatively. containing complexes of Ir, OS, Rh, and especially Ru are described. Properties of the Ni-Ir System On the Chemistry of Ruthenium E. BUCHER, w. F. BRINKMAN, J. P. MAITA and A. s. E. SCHLEITZER, Chem. 1970, 94, (6), 189-192 COOPER, Phys. Rev. By1970, I, (I), 274-277 z., Measurements of the lattice parameters, electronic Ru nitrosyl complexes are important in the specific heat, magnetic susceptibility and Debye reprocessing of used nuclear fuels. Aqueous Ru(II1) chloride solution contains complexes of temperature in 0-100 at.04 Ir-Ni showed no ordering or decomposition after annealing for the type [RuX,(H,O), ,I3 with n=1-6, and several days at 500-1100°C. A sharp peak X=Cl, Br, I, BF4, or PF,. Ru and Ru-chloro occurred in the electronic specific heat/concentra- complex hydrogenation catalysts are discussed. tion curve at 85 at.04 Ni, together with a weak anomaly in the T3 term of the low temperature Properties and Reactions of Ruthenium(I1) specific heat. Susceptibility was measured on the Amine Complexes paramagnetic side only up to 79 at. 7; Ni, where a P. C. FORD, Coordination Chem. Lett., 1970, 5, spontaneous moment developed at low tempera- (0,75-99 tures. The synthesis, properties and reactions of a large number of Ru(1I) complexes with N-containing The W-Re-Ir Composition Diagram ligands are described. Complexes with and E. M. SAVITSKII, M.A. TYLKINA and L. L. ZHDANOVA, without Ti-acceptor ligands, with N,, N-hetero- Izv. Akad. Nauk S.S.S.R., Metally, 1970, (3), cycles, organonitriles, and with nitrosyls are 181-183 considered, as are substitution and redox reactions The W angle of the W-Re-Ir system was studied peculiar to the complexes. and ordering was investigated throughout the system. Ternary alloys which are cr-solid Electrical Transport Properties of IrO, solutions are produced at high temperatures. and RuO, From them can be produced bars, wires and sheet w. D. RYDEN, A. w. LAWSON and c. c. SARTAIN, by hot working, wire drawing and rolling res- Phys. Rev. By 1970, I, (4), 1494-1500 pectively. Electrical resistivities of single crystals of RuO,

Platinum Metals Rev., 1970, 14, (4) 149 and IrO, were measured at 10-1000 K. Hall Hydrogen Sorption by Palladium in Hydra- constants were obtained at 77 and 300 K. The zine Electro-oxidation temperature dependence of the resistivity is N. v. KOROVIN and B. N. YANCHUK, Electrochim. explained in terms of electron-photon and Acts, 1970, 15, (4), 569-580 electron-electron interband scattering. The amount of H, absorbed by Pd in N2H, electro-oxidation increases with anodic polaris- Thermal Conductivity and Lorenz Ratio of ation. H, is present in Pd after N,H, electro- RuO, oxidation at high positive potentials, (up to I .O V). J. MILLSTEIN, J. Phys. Chem. Solids, 1970, 31, H, is an intermediate product of N,H4 electro- (4), 886-887 oxidation and is probably produced by the Thermal conductivity and Lorenz ratios of very decomposition of intermediate radicals. pure RuO, crystals were investigated. Con- ductivity/temperature curves show that cr=8.42 x On the Interaction of Carbon Monoxide with IO-~cm deg KI-nIW, py18.1 cm deg K"W, and an Iridium Electrode Catalyst n=r.66. At low temperatures the Lorenz ratio A. B. FASMAN, G. L. PALIYUKOVA and D. v. SOKOL'SKII, reached a constant value of (2.60*0.1) x Elektrokhimiya, 1970,6, (6), 832-834 WQjdeg K', which is close to the theoretical Charging curves were obtained at 20, 30, 50, and value of 2.45 x IO-~ WQjdeg K2. 70°C for Ir electrodes in I N H,S04 in the presence of H2. CO reduces the Slade potential Refinement of the Crystal Structure of more than with Pt or Rh. Ruthenium Dioxide c.-E. BOMAN, Acta Chem. Scand., 1970, 24, (I), Electrosorption of Molecular Oxygen from 116-122 Aprotic Solvents on Noble Metal-Mercury RuO,, which has a rutile structure, crystallises in Alloys space group p4,jmnm of the tetragonal system. w. LUND and M. E. PEOVER, J. Electroanal. Chem. The unit cell contains two formula units, and has Interfac. Electrochem., 1970, 25, (I), 19-25 and V= dimensions a=4.491, c=3,106 8 Chronocoulometry shows that 0, is adsorbed on 62.68 A3. alloys of Hg with Pt, Au, Ir, and Rh from Precision Determination of the Crystal solutions in acetonitrile, dmf and dms reaching Structure of Osmium Dioxide 200-800 pC/cm'. Adsorption depends on alloy Ibid., 123-128 composition, electrode potential and 0%concentration. Double layer capacity increases with OsO, has a rutile structure crystallising in space alloy formation. group ~4~:mnrnof the tetragonal system with two formula units per unit cell. Unit cell dimensions are a=4.500 A, c=3.183 8, and V=64.48 A3, ELECTRODEPOSITION AND SURFACE COATINGS Some New Organometallic Compounds of Osmium Tetracarbony1 Internal Stresses of Platinum Coatings on F. L'EPLATTENIER, Chimia, 1970, 24, (4), 151-152 Titanium I. E. VESELOVSKAYA and N. I. SHERSTYUK, Zashchita The reactions of 0s carbonyl compounds with Hz and ally1 halides were studied. Dialkyl Metal., 1970, 6, (3), 302-305 complexes, e.g., cis-Os(CH,),(CO), and cis- The internal stresses arising during electrode- OS(C,H,),(CO)~,were isolated and their struc- position of Pt on Ti are discussed and optimum tures and spectral were determined. Their conditions for formation of coatings with mini- reactions with CO at elevated temperature mum internal stress are described. and pressure were studied; the former was converted to Os(CO), and the latter to cis- LABORATORY APPARATUS Os(COC,H,),(CO),. AND TECHNIQUE ELECTROCHEMISTRY An Automatic Spherical High Temperature Adiabatic Calorimeter The Oxidation of Hydrazine in Alkaline F. R. SALE,J. Phys. E, Sci. Instrum., 1970, 3, (8), Solution at Platinum and Mercury 646-650 J. A. HARRISON and Z. A. KHAN, J. Eleciroanal. The calorimeter, which was developed for deter- Chem. Interjac. Electrochem., 1970, 26, (I), 1-11 mination of specific heats and enthalpies of trans- The mechanism of N,H, oxidation in alkaline formation of Fe alloys at 650-1750 K, has f1.216 solution was investigated at Pt and Hg. On Pt reproducibility and & 1.5"i, absolute accuracy for the oxidation is a surface process involving a fast an enthalpy of transformation of 923 J /g.atom at three-electron transfer preceding a one-electron I 184 K. Energy is supplied to the specimen by a rate-determining step. The reaction is fourth small IO?/" Rh-Pt immersion heater which also order in HO-. supports the specimen in the inner spherical

Platinum Metals Rev., 1970, 14, (4) 150 chamber. Temperature distribution in the possesses reduced activity for hydrocracking calorimeter is measured with Pt:royo Rh-Pt hydrocarbons but the introduction of Mn in thermocouples at the poles and equators. atomic ratios to Pt of I :IS, I :IO, I :5 increases the activity of Pt:Al,O, for isomerisation of fi-C,HI4. Production of Micro-steam Quantities for Dynamic Gas Flow Reactors Deactivation of Platinum/Alumina Re- M. LANDAU, M. J. LANGFORD and G. SNIEZO-BLOCKI, forming Catalysts by Carbon Deposits C.hem. & Znd., 1970, (May z), 591-592 N. M. SHAIMARDANOV, M. A. TATAMAROV and M. E. A cell capable of giving as little as 3 ml of steam LEVINTER, Zbid., 371-375 per minute was constructed using 1% wire C is deposited mainly on the active Pt centres electrodes wound on glass formers to electro- during dehydrocyclisation of n-C,H,,. De- lytically convert water to H, and 0,, and Pt/ activation of Pt/Al,O, by C during dehydro- asbestos to catalytically recombine them as steam genation of cyclohexane occurs by a reduction in as near as possible to the reactor to be dosed with the number of active centres and not by a decrease gas of consistent composition. in their activity. This is clear from the constancy of the activation energy for cyclohexane dehydrogenation at various stages of C deposition on HETEROGENEOUS CATALYSIS the catalyst. Differences between deactivations of Here’s How New Platforming Catalysts Are cyclohexane and HCOOH dehydrogenation are apparently due to heterogeneity of the active Pt Performing centres . E. A. SUTTON, oil Gas J., I970,68, (zo), 100-108 Summaries are given of results for four com- Studies of the Regularity of Crystallisationof mercial operations using the U.O.P. R-16 Re-Pt catalyst and for one using the U.O.P. R-20 Platinum on Supports. IV. Effect of Con- catalyst. The advantages of both are given and ditions of Preparation on the Dispersion of results are compared. Both allow greater through- Platinum put and increased operating severity with higher N. M. ZAIDMAN, N. P. KRASILENKO, L. M. KEFELI and yields of reformate and aromatics. Regeneration I. D. RATNER, Kinet. Kataliz, 1970,II, (3), 741-746 is less frequent and catalyst investment is re- Studies of factors affecting the dispersion of Pt duced. R-zohas a significant selectivity advantage in Pt/Al,O, showed that there is reduced dis- in favour of Platformate and aromatic yields. persion when the support is roasted at a lower temperature than normal or when various Production of Petrol with Octane Number 95 chemical reagents are used to treat the support. at Industrial Catalytic Reforming Plant D. V. IVANYUKOV, E. F. KAMINSKII, G. N. Dehydrocyclodimerisation. I. Dehydrocyclo- MASLYANSKII, A. P. PEDOROV, R. N. SHAPIRO, V. V. dimerisation of Butanes over Supported SHIPIKIN and V. YU. GEORGIEVSKII, Khim. Tekhnol., Platinum Catalysts Topliv Masel, 1970, (3), r-5 S. M. CSICSERYJ. Catalysi.7, 1970,17, (z), 207-215 A reforming unit was modernised by replacing Dehydrocyclodimerisation, which converts C,, F-promoted AP-56 catalyst with AP-64 C1- C, and Ci paraffins to aromatics, is carried out at promoted Pt/Al,O,, which has superior stability, 430°C with dual-function catalysts possessing activity and selectivity. dehydrogenation and acid-type activity. Tests with 0.87~ Pt/AI,O, showed that the principal Isomerisation of n-Butenes and n-Butane in aromatics formed from C,H,, are xylene and the Presence of Group VIII Metals on toluene with smaller amounts of C,H, and C, Aluminium Oxide and C,, aromatics. Using strongly acidic catalyst, G. M. PANCHENKOV, G. S. VOLOKHOVA and W. M. product distribution from iso- and n-butanes is ZHOROV, Neftekhimiya, 1970, ID, (2), 178--182 identical. Ethylbenzene and styrene are the main Group VIII metals are active in the double bond C, aromatics formed from n-C,H,, over weakly and cis-trans isomerisations of n-C,H, and of acidic catalyst. n-C,H,,. Activity for skeletal isomerisation 11. Dehydrocyclodimerisation of Propane varied in the order Conaphthalene and other condensed aromatics, from 0. v. ANDREEVA, YU. M. VOLODIN and R. I. C,H,,. Ultimate recycle yield and conversion to IZMAILOV, Zbid., (3), 355-358 aromatics increase with increasing C number of Pt/Al,O, catalyst containing 0.014 wt.O, Mn the initial light paraffin.

Platinum Metals Rev., 1970, 14, (4) 151 IV. The Reactions of Butenes cycloparaffins and n-paraffins over 5% pt/ Ibid., (31, 323-330 asbestos were determined by chromatography. Cyclane molecules were oriented to the surface by To clarify the role of olefins as possible key CH8 groups containing transannular atoms intermediates in this process, C,H, was reacted H when in atmosphere but in atmosphere over Pt/A1,0, and the product contained a large H, N, fraction of C,-C, olefins and naphthenes. These they were oriented by the maximum number of CH, groups. The difference in entropy of ad- and some aromatics also form over acidic catalysts sorption of cycloparaffins in the two atmos- with no dehydrogenation component. Results pheres was calculated. The high reactivity of indicate that dehydrocyclodimerisation proceeds via conversion of light paraffins to olefins, medium-sizcd cycloparaffins in transannular dimerisation of these olefins and aromatisation of dehydrocyclisation is due to the specific orientation of their molecules on the catalyst the dimers. surface by reacting C atoms. Effect of Heat Treatment on the Catalytic and Physical Properties of Pt/Al,O, Ad- Kinetics and Mechanism of Oxidation of sorption Catalysts Carbon Monoxide on Platinum, Purified in High Vacuum S. A. KHASSAN, G. I. EMEL'YANOVA, V. P. LEBEDEV I. I. TRET'YAKOV, A. V. SKLYAROV and B. R. SHUB, and N. I. KOBOZEV, Zh. Fiz. Khim., 1970,44, (6), (I), 166-175 1469-1474 Ibid., Studies of the sintering of Pt/Al,O, at various A scheme is proposed for the oxidation of CO on stages of charging with Pt showed that in vacuum Pt, purified in high vacuum at IO-~-IO-~torr, a steady amount of activity and surface is reached 175-IOoo"C. The reaction proceeds by a shock at each stage. Isochronous sintering has a mini- mechanism between adsorbed 0, and CO from mum at 300-40OCc.A decrease in activity during the gaseous phase. roasting is accompanied by a decrease in surface area and a decrease in size is accompanied by a Determination of Surface Area by Chemi- drop in the number of Pt crystals. The number of sorption: Unsupported Platinum active centres on the catalysts was determined. M. A. VANNICE, J. E. BENSON and M. BOUDART, J. Caralysis, 1970, 16, (3), 348-356 Dehydrogenation of Dicyclohexyl over a Adsorption of H, and 0,, as well as reaction of K,, Platinum-Alumina Catalyst without Added was studied gravimetrically and volumetrically on Hydrogen Pt black. H20formed leaves the surface but is not replaced by additional H,. Amount of H, A. w. RITCHIE and A. c. NIXON, Engng. Chem., Id. adsorbed is the same on a reduced and evacuated Product Res. Dev., 1970, 9, (2), 213-219 surface as on a preoxidised surface. Ratio of The effects of pressure, temperature and space adsorbed H and 0 atoms to surface Pt atoms is velocity on the rates of reaction over Pt/Al,O, close to unity at room temperature and 50 torr. were determined in the range 10-30 atm, 700- 1300°F. High selectivity for the production of diphenyl was favoured by high temperature, high The Problem of Standardising Pt-Catalysts conversion and low pressure. A. M. SOKOL'SKAYA, A. P. GOROKHOV and s. A. RYABININA, Vest. Akad. Nauk Kaz. S.S.R., 1970, 26, (2), 66-67 The Form of Active Centres of Adsorption Exact control of alkali metal cation content is Platinum Catalysts in Vapour-phase Pro- required to produce at PtO, catalyst most cesses suitable for a given reaction. The electrochemical N. I. KOBOZEV, ZH. V. STKEL'NIKOVA and L. E. potential of Pt black varies inversely with cation MARTYSHKINA, Zh. Fix. Khim., 1970, 44, (4), content and indicates the degree of purity of 1059-1064 PtO,. Hydrogenation rate of compounds with Active centres of Pt/SiO, catalysts for vapour- various types of chemical bonds depends on the phase hydrogenation of cyclohexene and de- potential of the Pt black. hydrogenation of cyclohexane are pairs of Pt atoms [R],,as established during the reduction On the Effect of the Structure of Nedium of CH,.CO.CH,, which showed that reduction Size Cyclanes on their Catalytic Reactions of the C=O bond requires the proximity of two in the Presence of Platinum Pt atoms each with two frec valencies. A. A. VEDENYAPIN, E. S. BALENKOVA and S. I. KHROMOV, Vest. Moskov. Univ., Ser. IZ, Khim., On the Orientation of Cyclic Hydrocarbons 1970, 24, (2), 245-257 with Medium-sized Rings in the Adsorption Studies of the reactions of C, and C,, cyclo- of Complexes on Platinum Catalysts paraffins on Pt/C showed the kinetics of de- A. A. VEDENYAPIN, E. S. BALENKOVA and S. I. composition of cyclooctane, cyclononane and KHROMOv, Kinet. Kataliz, 1970, 11, (3), 676-682 cyclodecane, whose reactivities depended on their Differential heats of adsorption on C,-C,, structures.

Platinum Metals Rev., 1970, 14, (4) 152 Hydrogen Chemisorption and Surface Com- catalyst does not depend on temperature, and is position of Silica-supportedPlatinum-Copper not influenced by catalyst poison, but increases Alloys with H, partial pressure, Hydrogenation and J. H. ANDERSON, P. J. CONN and S. J. BRANDENBERGER, isomerisation probably proceed on identical J. Catalysis, 1970, 16, (9, 326-331 catalytic centres, their extent being governed by the strength of the olefin-active centre bond. 9,14, 19, and zs0: Cu-Pt alloys were formed into 5 and 0.55 wt.7; metal/SiO, catalysts. Surface composition of alloy crystallites depended upon Fundamental Studies on Supported Pal- crystallite size; the larger the crystallite, the more ladium Catalysts the surface was enriched with Cu. Surface M. UHARA, T. YAMABE and s. SUZUKI, Kogyo composition of 30a crystallites approached that of Kagaku Zasshi, 197473, (z), 252-256 their interior. The amount of H, adsorbed on a PdjC catalyst is much larger than on Pd wire or Pd black under The Hydrogenation of Ethylacetylene. 111. the same conditions. The specific surface area Reaction of Ethylacetylene with Hydrogen has a great effect on the absorption isotherm. The Catalysed by Platinum and Iridium relation between the specific surface area of Pd and the amount of Haabsorbed was studied using R. s. MANN and K. c. KHULBE, Ibid., (I), 46-53 Pd/Si02-Al,08. When ethylacetylene and H, reacted over pumice- supported and unsupported Pt and Ir at 2o-8oDC Asymmetric Hydrogenation Using Modified in various reactant ratios, the orders of reaction with respect to ethylacetylene and H, were zero Cellulose-Palladium Catalysts and one, respectively. Overall apparent activation K. HARADA and T. YOSHIDA, Naturwissenschaften, energies were determined. Changes in selectivity 1970, 57, (3), 131 and activity in relation to physical properties are Benzoylformic acid and cc-acetamidoacrylic acid discussed. were hydrogenated using a series of Pd/cellulose catalysts to mandelic acid and alanine respectively. The products were of high optical purity, which Vinyl Acetate. Vapour-phase Process was not obtained when unmodified catalysts were Br. Chem. Engng., 1970, 15, (s), process scan used. The celluloses used were carboxymethyl The Hoechst-Bayer vapour-phase process for the cellulose, aminoethyl cellulose and diethylamino- catalytic conversion of C,H,, CH,COOH and 0, ethyl cellulose. to vinyl acetate uses noble metal fixed bed catalysts, e.g., 0.1-2.0 wt.9; Pd on A1,0, and/or Asymmetric Hydrogenation Using Modified SiO,. An alkali acetate moderator improves the Ion Exchange Resin-Palladium Catalysts yield but requires constant replenishment. Ibid., (6), 306-307 91-94y0 selectivity is achieved and activity remains high for several months. Fluidised bed The same hydrogenations as above were carried technique is also possible. out using a l'd-resin complex. The carboxylic acid resin was modified with optically active L-alanine or L-phenylalanine to give optically The Mechanism of the Palladium-catalysed active products. Synthesis of Vinyl Acetate from Ethylene in a Heterogeneous Gas Reaction The Change of Adsorption and Catalytic S. NAKAMURA and T. YASU1,J. Catalysis, 1970, 17, Properties of Rh Black in the Presence of (3)J 366-374 Cations Studies of Pd in the synthesis of vinyl acetate L. A. BEKETAEVA, G. D. ZAKUMAEVA and D. V. from C,H, suggest that C,H, and CH,COOH are SOKOL'SKII, Kinet. Kataliz, 1970, 11, (3), 704-709 activated by abstraction of H by Pd, (even when 0 'Tests in H,SO, electrolytes with additions of Cd, is absent for C,H, whereas it only occurs for T1, and Zn sulphates and of Pb acetate showed CH,COOH when 0 is present). Vinyl acetate that the amount of H, absorbed on Rh black is produced by combining dissociatively adsorbed decreases as the cation concentration rises. Thus CH,COOH and C,H,, which is the rate-deter- hydrogenation of dirnethylacetylenylcarbinol and mining step in industrial reactions. Co-catalysts, of butyn-1-01-3 on modified Rh black is slower e.g., K or other alkali metals, promote abstraction than on Rh black without cations. of H from CH,COOH and weaken Pd-0 bonds in dissociatively adsorbed CH,COOH. Catalytic Properties of Iridium Deposited on Alumina. 111. Application of Thermo- Study of Catalytic Hydrogenation in Liquid desorption to the Study of Adsorbed Am- Phase monia L. ~ERVEN+, v. ZAPLETAL and v. RU~I~KA,Chem. J. r. CONTOUR, J. PAGNIET and G. PANNETIER, BUZZ. Pritmysl, 1970,20, (4), 160-164 SOC.Chim. Fr., 1970, (I), 75-79 The selectivity of hydrogenation on a Pd/C NH, adsorbed on y-Al,O,, Ir/A1203and Ir/SiO,

Platinum Metals Rev., 1970, 14, (4) 153 was studied by thermodesorption. The desorption HOMOGENEOUS CATALYSIS activation energy was studied as a function of surface coverage from which the desorption sites Intramolecular Aromatic Substitution in energy distribution was calculated. For Ir /A1,0, Transition Metal Complexes catalyst the desorption activation energy is 10.7 G. w. PARSHALL, Accounts Chem. Res., 1970, 3, kcaljmole and is independent of the surface (4)J 139-144 coverage. An aryl C-H bond in a donor ligand of a transition metal complex reacts with the central metal atom Catalytic Reactions in an Ultrasonic Field to form a metal-C bond. The H originally A. N. MAL’TSEV and I. v. SOLOV’EVA, Zh. Fiz. Khim., attached to C adds to the metal to form a metal-H I97OJ 44, (4)9 1092-1094 bond or is eliminated as Hf. This reaction is An ultrasonic field acting on an aqueous N,-H, generally intramolecular and involves an ortho solution in the presence of Pt-, Rh- and Pd-blacks H bond of an aromatic N- or P-donor ligand. Reactions involving these ligands and complexes increased the NH, yield from 2 up to 6.5 times with the greatest yield using Rh. An ultrasonic of Pt, Pd, Ir, Rh, and Ru are reviewed and the field during H,O, decomposition on Pt, Rh and catalytic activity of triarylphosphine complexes is related to the studied mechanism. Pd showed increased activity up to 10 times on Pt black, up to 2.5 times on Rh black but lower activity on Pd black. Change of activity was Reactions of Acetylenes with Noble-metal related to quantity of catalyst, e.g., reduction from Halides. VIII. The Palladium Chloride 5 to I mg increased the activity of I’d by up to 4.5 Catalysed Trimerisation of 2-Butyne and times. 1-Phenyl-1-propyne H. DIETL, H. REINHEIMER, J. MOFFAT and P. M. On the Relation of the Stereochemistry of MAITLIS,~. Am. Chem. soc., 1970, 92, (8), 2276- Hydrogenation of Cyclo-olefins to the Nature 2285 of the Catalysts - Refractory Group VIII A series of these reactions was carried out. The Metals mechanism was examined. 0. v. BRAGIN, L. v. POZDNOVA and A. L. LIBERMAN, IX. The Decomposition of the Complex Akad. Nauk S.S.S.R., Ser. Khim., 1970, (6), Izv. [CI(Me,C,),PdCI],, Particularly to Vinyl- 1319-1325 pentamethylcyclopentadiene The activity of Group VIII metal catalysts for H. REINHEIMER, J. MOFFAT and M. MAITLIS, Ibid., liquid-phase hydrogenation of methylcyclopen- P. tane decreases in the order: Pt>Rh>Pd>IrS 2285-2294 Os>Ru>Co. Studies of the stereochemistry of The mechanism of this reaction is discussed. hydrogenation of dialkylcyclopentanes over Pt /C, Pd/C, Rh/C, and Ir/C showed that the mixture of Organic Syntheses by Means of Noble steroisomeric 1,z-dialkylcyclopentanes produced Metal Compounds. XLI. Reaction of Iso- was richer in the trans isomer over Pt/C and cyanide with Allyl-palladium Chloride Pd/C, and richer in the cis isomer over RhjC n- KAJIMOTO, H. TAKAHASHI and J. TSUJI,J. Organo- and especially over Ir/C. A new mechanism for T. the hydrogenation of substituted cyclo-olefins is metal. Chem., 1970, 23, (I), 275-280 discussed. The treatment of cyclohexyl isocyanide with it-ally1 Pd chloride in C,H, at room temperature gave di- pAdoro-bis[ I -(cyclohcxylimino)-3- Liquid-phase Hydrogenation of cis- and butenyll-bis(cyclohexy1is0cyanide)dipalladium by trans-Cyclodecenes over Group VIII Metals the insertion reaction, whose progress was V. I. ALEKSEEVA, E. S. BALENKOVA, L. E. MARININA followed by NMR spectroscopy. and s. I. KHROMOV, ATefzekhimiya, 1970, 10, (3), 315-320 The constants were determined of the ratios of Kinetics and Mechanism of the Oxidation of hydrogenation of cis-cyclodecene over Pt, Ir Olefins by Palladium Salts and Rh blacks, of trans-cyclodecene over Pt and I. I. MOISEEV, Kinet. Kataliz, 1g70,11, (z), 342-356 Ir blacks, and of the rates of isomerisation of Experimental data are reviewed for the equili- tram- to cis-cyclodecene over Pt, Ir and Pd brium formation of olefin it-complexes of Pd and blacks. The hydrogenation rate constants of for the kinetics of redudon of Pd salts by olefins cyclo-olefins are related to ring size, which is in hydroxyl-containing solvents. The reduction connected with the pressure of the cycloparaffins includes the intermediate formation of x- formed; the higher this pressure, the less is the complexes, their conversion into u-bonded rate constant of hydrogenation of the initial organopalladium compounds, and their hetero- cyclo-olefin. Both cis- and trans-forms of cyclo- cyclic decomposition, The mechanism of x-u decene are reduced at the same rate during this isomerisation and of the decomposition of reaction. organopalladium compounds is discussed.

Platinum Metals Rev., 1970, 14, (4) 154 Ligand Factors in the Isomerisation of Homogeneous Olefin Hydrogenation over Olefins by Palladium Complexes Oxidised Rhodium Complexes w. H. CLEMENT and T. SPEIDEL, Ind. Engng. Chem., R. L. AUGUSTINE and J. F. VAN PEPPEN, Ibid., Product Rex. Dew., 1970, 9, (z), 220-223 571-572 Studies of the equilibrium isomerisation of I- Hydrogenation of oxides obtained by oxidation of hexene in methyl chloride catalysed by a series of [Rh(Ph,P)CI] in C,H,OH and C,H, gives 1,3-dichloro-2- hex- i-ene-4-(pZpyridine-N- materials capable of olefin hydrogenation but oxide)Pd(II) complexes showed that it is sensitive double-bond isomerisation occurs in the reaction. to the electronic nature of the tranx N-oxide Hydrogenation of these species in the presence of ligand, isomerisation only occurring when this Ph,P gives catalysts much more active for olefin ligand dissociates from the Pd-oleiin complex. hydrogenation and which also inhibit isomeris- When the complex contains a strongly electron- ation. withdrawing ligand the equilibrium favours free ligand and the catalyst system is then very effective. Homogeneous Catalytic Hydrogenation of x,a-Unsaturated Nitro Compounds Using Polymerisation of Butadiene by Rhodium Triarylphosphine-rhodium Complexes Trichloride in Aqueous Medium R. E. HARMON, J. L. PARSONS and s. K. GUPTA, Org. Prep. Proced., 1970,z, (I), 25-27 F. MIKES and J. KALAL, Chem. Prhrysl, i970, 20, (5), 218-221 RhCl(Ph,P), and trichlorotris [(4-biphenylyl) K formate and saturated aldehydes increase the (I-naphthyl)phenylphosphine]rhodium(III) were rate of butadiene polymerisation by RhCl,, used as homogeneous catalysts for the probably due to the reducing action of these hydrogenation of +unsaturated nitro com- compounds, which support the Rh having a lower pounds. degree of oxidation. Even low concentrations of K acetate lower the polymerisation rate. Synthesis of Trichlorotris(4-hiphenyl-l- napthylphenylphosphine)rhodium( 111). New Hydride Transfer Reactions Catalysed by Octahedral Complex Rhodium-Tin Complexes R. E. HARMON, J. L. PARSONS and S. K. GUPTA, H. B. CHARMAN, J. Chem. SOC.,B, Phys. Org., Org. Prep. Proced., 1970, 2, (I), 19-23 197% (4)1 584-587 The complete synthesis of this complex is des- Rh-Sn chloride complexes catalyse dehydro- cribed. This complex is another potential homo- genation of isopropyl alcohol to acetone, and H-D geneous catalyst. exchange between the a-CH and OH group of the alcohol. Reaction mechanisms are suggested. Use of Transition Metal Complexes as Rhodium Catalysts for the Homogeneoufi Selective Hydrogenation Catalysts Hydrogenation of Ketones J. E. LYON, L. E. RENNICK and J. L. BURMEISTER, Ind. R. K. SCHROCK and J. A. OSBORN, J. Chem. SOC.,D, Engng. Chem., Product Res. Dev., 1970,9, (I), 2-20 Chem. Commun., 1970, (9), 567-568 Several specific examples of selective catalysis by [RhH,X,L,]+ complexes, where L=solvent and noble metal complexes are given. Catalysts X=PPh,Me, PPhMe, or PMe,, catalyse the discussed include: IrX(CO)(Ph,P),, where X=H reduction of ketones under mild conditions, when or halogen; IrH3(Ph3P),; (PhJ?),MCI,, where promoted by small amounts of H,O. M=Pt or Pd; and especially complexes of Rh with Ph,P, CO, H, and halogens. Desulphonation of Aromatic Sulphonyl Halides Catalysed by Some Platinum-metal Complexes CORROSION PREVENTION J. BLUM and G. SCHARF, J. org. Chem., 1970, 35, (6), 1595-1899 Anodic Behaviour of Pb-Pt Bielectrodes in Desulphonylation of arenesulphonyl chlorides Low Salinity Electrolytes and bromides using RhCI(PPh3),, RhCI(C0) H. HELBER and E. L. LITTAUER, Corrosion scd., 1970, (PPh,),, IrCl(CO)(PPh,),, RuCl,(PPh,),, and 10, (6), 41 1-419 PdC1, catalysts is assumed to proceed mainly The Pb-Pt bielectrode was studied in various by a metal ion-promoted mechanism and partly salinities. A thin film of PbO+PbS formed on by homolytic decomposition. A theory of the the surface aids PbO, formation and growth. former accounting observations includes the steps In solutions 20.1 M NaCl the Pt microelectrode ArSO,IrCl,(CO)(PPh,), + ArSO,IrCl,(CO) influences the sequence of events leading to the (PPh,) + ArIrCI,(CO)(S02)(PPh,) and loss of initial passivation prior to PbO, formation and SO, from the last compound. Some new Rh and subsequently is vital to the nucleation and Ir complexes are described. growth of PbO,.

Platinum Metals Rev., 1970, 14, (4) 155 ELECTRICAL AND ELECTRONIC metallising to the passivation surface. Pt acts as a diffusion barrier to subsequent Au deposition. ENGINEERING Beam Lead Technology TEMPERATURE M. E. HUTTON, Microelectronics, 1970, (April), MEASUREMENT 32-35 Beam leads of Au for Si monolithic circuits are Investigations on Very Thin Thermocouple produced in four stages: passivation, metal Wires Made from Noble Metal Alloys deposition, circuit delineation, and chip separa- M. MAJDIC and R. TILMES, Prakt. Metallog., 1970, tion. During the second stage a thin layer of Pt 7, (2)>73-83 is sputter-deposited over the whole slice and Measurements with 20 ym diam. wire 52*, sintered into the contact window areas to produce Au-46*/, Pd-2"/, Pt:5:: Rh-gSOb Pt thermo- Pt silicide. Excess Pt is etched away without couples were irreproducible because of deform- masking. Layers of Ti and Pt are then deposited ation of the wire but a heat treatment was in sequence over the whole slice. Ti keys the developed to standardise the structure.

NEW PATENTS

METALS AND ALLOYS spinnerettes consists of: 50-80 wt.% Au, 0.04-0.5 wt.u/, Ir and the remainder Pt. Preferred quanti- Silver Alloy for Electrical Contacts ties are 70,0.2 and 29.8 wt.O& respectively. TEXAS INSTRUMENTS INC. British Patent 1,19I,675 Dispersion Hardened Metals and Alloys An improved alloy for contacts consists of 1-207; JOHNSON MATTHEY & CO. LTD CdO, 0.001-0.50~Ru or Hg and the balance Ag. Dutch Appl. 69.10,671 The Ru is superior to Co in increasing the erosion The metal or alloy to be hardened is flame resistance of Ag Cd oxide alloys. sprayed with a reactive component which is then converted to a dispersed phase component. The Sheathed Metal examples show the use of the process in hardening JOHNSON MATTHEY & CO. LTD precious metals and alloys. British Patent 1,195,349 A core of W or Mo or a W-Mo alloy is sheathed CHEMICAL COMPOUNDS with a Pt group metal, or an alloy based on at least one 13 group metal. A barrier layer is Ruthenium Tetracarhonyl Trimer disposed between core and sheath, and pot in the RHONE-POULENC S.A. interfacial space is reduced to < I p. British Patent I,189,255 [Ru(CO)J8 is prepared by heating CO with a tris Palladium-Iridium Alloy for Glass Fibre (8-dionato)Ru at 100"to 250'C and atmospheric Production pressure in an alcohol boiling between 100' and 25oOC. OWENS-CORNING FIBREGLASS CORP. US.Patent 3,488,172 Osmium Carbonyl A bushing fabricated from an alloy containing JOHNSON MATTHEY & CO. LTD 95-99.704 Pd and 5-0.3'34 Ir by weight made by U.S. Patent 3,508,870 melting and casting under a vacuum of about A method of preparing 0s carbonyls wherein a I mm of Hg can be used for glass fibre production. solution of OsO, in an inert hydrocarbon solvent Platinum-Rhodium-Gold Alloy is heated at an elevated temperature at super- atmospheric pressure in the presence of CO. The JOHNSON MATTHEY & CO. LTD product is primarily Os,(CO),, with traces of German Awl. 1,533,284 os,o,(co),*. l't-Rh-Au alloys, suitable for use in contact with molten glass, consist of: 60-97 wt.% Pt, 2-25 ELECTROCHEMISTRY wt.% Rh and 1-10 wt,yo Au. Electrochemical Cells Alloy LEESONA CORP. British Patent 1,199,017 JOHNSON hUTTHEY & CO. LTD A light-weight electrode consists of an expanded German Appl. 1,533,290 layer of a catalytic metal such as Au, Pd, Pt, Ir, An alloy suitable for use in the fabrication of Rh, Ru or 0s.

Platinum Metals Rev., 1970, 14, (4), 156-158 156 aromatic compounds is obtained by the dehydro- ELECTRODEPOSITION AND genation of mixed straight chain paraffins. The SZTRFACE COATINGS catalyst used is a composite of Pt, Pd or their Chemical Platinum Plating Process compounds on an A1,0, associated with an alkali metal or its oxide. A typical catalyst contains INTERNATIONAL NICKEL CO. INC. wt.74 Pt, wt.:’, Li and 0.50 wt.% AS U.S. Patent 0.75 0.50 3,486,928 on an A1,0, support. A method of depositing Pt alloys containing up to about zoo/, Rh, up to about 100; Ir and up to Catalytic Coatings about 10:; Ru on an active surface is described. E. I. DU FONT DE NEMOURS & CO. The bath used contains an alkaline Pt(Iv> British Patent 1,197,067 hydroxide solution with about 2-20 g/l Pt, an alkali metal hydroxide to give a minimum bath Walls of cooking devices exposed to organic products are coated with a mixture of enamel- pH of about 8, up to about I mole/l of a stabiliser an such as ethylamine, and up to about I g/1 N,H,. ling frit and a catalyst which may be one or more Pt deposits produced in the absence of the stabi- of Pt, Pd, Ru, Ag, Rh, 0sor Ir. See also British liser have catalytic properties whereas Pt and Patents 1,197,068and 1,197,069. Pt alloy deposits produced in the presence of the stabiliser are bright. Naphtha Reforming Catalyst CHEVRON RESEARCH CO. Stabilising Noble Metal Coatings U.S. Patent 3,487,009 JOHNSON MATTHEY & CO. LTD Reforming a naphtha in the presence of H, at German AppE. 1,916,791 low pressures to produce at least 98 F-1 clear Coatings of a Pt metal or alloy on another metal, octane gasoline is accomplished using a catalyst particularly Mo or W, are stabilised by reducing composed of a porous inorganic oxide carrier the interfacial pressure and replacing the 0, containing 0.01-0.5~/0Pt, o.o1-0.5~/,Re and by an inert gas. o.oo1-0.1~~Ir. See also 3,487,010. Production of Hydrogen Peroxide by the LABORATORY APPARATUS Anthraquinone Process AND TECHNIQUE DEUTSCHE GOLD UND SILBER-SCHEIDEANSTALT Sheathed Metals U.S. Patent 3,488,150 process for the production of H,O, by the JOHNSON MATTHEY & CO. LTD A A mixed British Patent 1,190,266 anthraquinone process is described. catalyst of Pd with another metal of the Pt group refractory metal or alloy article (not Mo or W) A (0.1 to 50?/,),especially Ir (preferably 5-30?/0), is sheathed in a Pt group metal or alloy, optionally is used as hydrogenation catalyst in the hydro- with an intermediate barrier layer of, for example, genation step giving improved selectivity and a rare earth metal carbide. Applications are stated activity. to be stirrers, crucibles, dies, etc. in contact with molten glass. Hydrogen Production UNION OIL CO. OF CALIFORNIA HETEROGENEOUS CATALYSTS U.S. Patent 3,490,872 Hydrogenation Catalyst H, is produced from CO and water by contacting them at 50-650°C and 1-5000 atm, with an E. J. HOFFMAN aqueous liquid phase containing from Britkh Patent O.OOI-IO~~, 1,189,096 of a Group VIII noble metal, oxide or salt and A catalyst such as a Group VIII metal or com- having a pH from 7.1-14. Contacting is carried pound (Ru, Rh, Os, Ir, Pt etc.) is used in the out on one side of a metallic membrane permeable production of liquid hydrocarbon fuel from coal, to H, and the resulting H, is passed through the membrane by maintaining a lower pressure on Palladium-Lead Catalyst the other side of the membrane. The Group VIII CHAS. PFIZER & CO. INC. noble metal catalyst is Rh, Ir or Pt. The H,- British Parent 1,189,693 permeable membrane comprises Pd or Pd-Ag A catalyst for selective hydrogenation of acetyl- alloy which also contains up to 7576 of Ir, Pt or enic to olefinic bonds is obtained by impregnating Rh. a support with a Pd salt and a Pt salt, and reducing the Pd salt to the metal. Composite Hydrocarbon Conversion Catalyst UNIVERSAL OIL PRODUCTS CO. Production of Alkyl Aromatic Compounds French Appl. 2,007,507 UNIVERSAL OIL PRODUCTS CO. The catalyst consists of a Pt group metal and Re British Patent 1,193,486 (as metal, oxide, sulphide or halide) deposited A hydrocarbon feedstock for the alkylation of on A1,0, and a crystalline aluminosilicate mixture.

Platinum Metals Rev., 1970, 14, (4) 157 HOMOGENEOUS CATALYSIS pt and Ru alloys are claimed to be the most efficient. Palladium Pi-Ally1 Complexes w. R. GRACE AND co. British Patent 1,193,560 Air or Oxygen Cells Complexes which may be used in the polymerisa- LEESONA CORP. British Patent 1,195,915 tion of bucadiene are complexes of Pd salts with In such cells, the consumable anode may consist allylic ligands. They are produced by the of CU or Ag, and the catalyst of the cathode a reaction of a nitrile complex PdX,(RCN), with finely divided Group VIII metal, e.g. Rh, Pd, a monoolefine boiling at 1~5-3oo'C. (X is C1, Ru, Os, Ir. The Group VIII metal may be Br, I, acetate or formate; R is a 1-4 C alkyl alloyed with Au or Ag. group). Suitable olefines are vinyl naphthalene and methyl styrene. CHEMICAL TECHNOLOGY Ammino Rhodium Compounds Hydrogen Purification JOHNSON MATTHEY & CO. LTD UNION CARBIDE CORP. British Patent 1,196,583 British Patent 1,195,852 A method is provided for synthesis of compounds In a plant for the continuous production of H,, of ammino ions of general formula after rhe removal of various deleterious ingredi- ents from the product gas stream, the H, is finally [HRh(NHJJ*+ purified by diffusion through Pd or a Pd alloy. in which the H is coordinated to Rh. The compounds are useful homogeneous hydrogenation catalysts. ELECTRICAL AND ELECTRONIC ENGINEERING Catalysts Film-type Conductors JOHNSON MATTHEY & CO. LTD PLESSEY CO. LTD British Patent 1,197,723 British Patent 1,190,195 Water-soluble unsaturated organic compounds, The conduction in an electrical resistance heater especially carboxylic acids, are catalytically is provided by a layer of oxide, or oxides, of hydrogenated in the presence of a Rh compound Ru, Rh, Pd, 0sand/or Ir. having a cation of formula: [HRh(NH3)J2+or [HRh(NH,),H,0]2+ Contacts for Semiconductors TEXAS INSTRUMENTS INC. Oxidation Catalyst British Patent 1,193,868 FARBWERKE HOECHST A.G. British Patent 1,197,843 A multilayered contact consists of the films: Vinyl acetate is obtained by the reaction of (a) vacuum-deposited Pt, (b) sputtered Mo, and C,H,, CH3COOH and 0, in the presence of Pd (c) a sputtered mixture of 957; Au and 5% Pt. acetate and a pyridine base. Sintered Composite Body Hydrogenation of Unsaturated Aliphatic JOHNSON MATTHEY & CO. LTD Compounds British Patent 1,198,616 LEVER BROS CO. US.Patent 3,489,778 A sintered composite body for an electric contact Unsaturated aliphatic compounds, especially soya is made by using a first part in the form of a rod oil, are catalytically hydrogenated by contacting (e.g. of Cu) to exert pressure on and supply them with H, in the presence of a solution of a current to a second part consisting of a mass of Pt compound, e.g. H,PtCl, and a stannous halide, powdered metal or alloy (Ag, Pt, Ag-CdO, etc.) e.g. SnCl,. A lower dialkyl ether, dialkyl ketone under conditions producing sintering of the mass or aliphatic carboxylic acid or its ester may be and bonding of the two components. used as solvent. Electric Contacts Hydroformylation Catalyst JOHNSON MATTHEY & CO. LTD JOHNSON MATTHEY & CO. LTD German Appl. 1,489,999 Dutch Appl. 69.I 1,827 A multiple electrical contact assembly consists of Unsaturated olefinic compounds are hydro- a metal backing strip, to which individual contact formylated in the presence of a phosphine com- elements are secured in pre-determined positions plex of a Rh hydride, e.g. RhH(CO)(PR,),. so that individual contact assemblies (consisting of one or more contacts and a carrying arm) may FUEL CELLS be stamped from the strip. The contact elements may be made of a noble metal such as Ag, Au, Fuel Cell Pt or Pd or an alloy thereof, and the backing GENERAL ELECTRIC CO. British Patent 1,193,660 strip of a base metal. Locating holes are provided In a cell for oxidising a 1-3 C alcohol, anodes of to facilitate location in a press tool.

Platinum Metals Rev., 1970, 14, (4) 158 AUTHOR INDEX TO VOLUME 14

Page Page Page Page Acres, G. J. K. 2, 78 Burnett, A. P. 105 Fadeev, V. S. 68 Iga, A. 30 Addink, C. J. 30 Bursian, N. R. 109 Fahey, D. R. 111 Imamura, S. 34 Affrossman, S. 68 Burwell, R. L. 69 Fasman, A. B. 150 Inoue, Y. 68 ha,K.4. I10 Burylev, B. P. 66 Fedorov, G. I. 109 Ivanova, G. V. I05 Ailon, D. C. 71 Butler, J. N. 68 Figueras, F. 1 09 Ivanovskii, M. D. 32 Alchudzhan, A. A. 33 Firth, J. G. 34 Ivanyukov, D. V. 151 Alekseeva, V. I. 154 Fischer, G. 64 Iyengar, L. 66 Allard, K. D. 109 106 Calvert, E. D. 29 Flanagan, T. B. 67, 106 bmailov, R. I. Anderson, J. €1. 153 Cant, N. W. 110 Fomichev, Yu. V. 109 Anderson, R. B. 111 Cathro, K. J. 71 Foner, S. 148 Andreeva, 0. V. 151 Cemeny, L. 153 Ford, P. C. 149 Jain, S. C. 64 Angus, H. C. 63 Chaldecott, J. A. 24 Fujiwara, Y. 35, 70 Johnson, B. F. G. 30 Arakawa, E. T. 148 _, Chan, J. P. 65 Armstrong, R. L. b6 Charman, H. B. 155 Garanin, V. I. 69 Astakhova, R. K. 108 Kadar, G. 148 Chen, H. S. 30 Garifzyanov, G. G. I10 Augustine, R. L. 112,155 Kajimoto, T. 154 Chernova, G. P. I08 Gaudio, D. A. 109 Kakovskii, 1. A. 31 Chimarova, L. A. 110 Gerberich, H. R. 1 10 Kalal, J. 111,155 Chomka, W. 147 Gersdorf, R. 147 Baggerud, A. 20 Churina, D. Kh. 68 Giannetti, J. P. 67 Kaminskii, E. F. 151 Clark, C. R. N. 11 Kane-Maguire, L. A. P. Bagotsky, V. S. 33 Gibbens, H. R. 110 31 Balenkova, E. S. 33, 152, Clarke, J. K. A. I10 Giessen, B. C. 30 Karzhev, V. I. 109 154 Cleare, M. J. 108 Gilbert, J. D. 71 Balovnev, Yu. A. 64 Clement, W. H. 155 Katz, E. R. 149 Gillard, R. D. 50, 66 Kawashima, R. 47 Baranowski, R. 65 Conn, G. A. 32 Giner, J. 68 Barber, W. A. 31 Conn, P. J. 153 Kay, D. A. R. 105 Godecke, T. 29 Keim, W. 32 Basolo, F. 31 Contour, J. P. 69, 153 Goodrich, D. 30 Battiste. M. A. 34 Cooke, D. F. 66 Keller, R. 148 Gorbunov, V. I. 105 Kempling, J. C. 11 I Beall, R. A. 29 Cooper, B. J. 109, 133 Gorokhov, A. P. 152 Becker, J. Y. 35 Copeland, M. I. 30 Kenahan, C. B. 32 Gostunskaya, I. V. 68 Ketterson, J. B. 107 Beecher, R. 69 Corkhill, J. R. 71 Graham, W. R. 32 Begetova, I. S. 65 Craddock, J. H. 70 Khairullim, R. Z. 33 Gratsianov, Yu. A. 105 Khan, Y. 147 Beketaeva, L. A. 153 Criscione, J. M. 31 Griffith, W. P. 108 Belson, J. 147 Csicsery, S. M. 151 Khan, Z. A. I50 Gubieva, D. N. 29 Khassan, S. A. 152 Benson, J. E. I52 Guertin, R. P. 148 Besnus, M. J. 64 Khodkevich, S. D. 108 Bhan, S. 29 Khrushch, A. P. 70 Daniels, J. 64 Khulbe, K. C. 33, 153 Biegler, T. 31 Danno, S. 34 Hall, W. IC. 110 Bignell, A. J. L. II Harada, K. 153 Kleshchev, N. F. 130 Darling, A. S. 54, 95, 124 Kleykamp, H. 107, 149 Bikbulatov, I. Kh. 110 Davlesupova, R. G. 33 Harmon, R. E. 35, 70, 155 Knight, R. A. 66 Bingham, R. E. 30 Dellby, B. 148 Harris, I. R. 30 Kobozev, N. I. 69, 109, Blue. E. M. I09 Diamond, J. M. 71 Harrison, J. A. 150 152 Blum, J. 35, 70, 155 Dietl, H. 154 Hartley. F. R. 62 Koch, R. K. 29 Bobanova, Zh. I. 34 Dobrev, E. 32 Hatcher, W. J. 69 Koffler, S. A. 29 Boerstoel, B. M. 148 Domnikov, L. 32 Heaton, B. T. 66 Kolutusha, B. I. 67 Rogdanovskii, G. A. 34, Donkersloot, €1. C. 106 69 Helber, H. 155 Korovin, N. V. 150 Dubinin, E. L. 65 Bogenschutz, A. F. 53 Hershman, A. 70 Korsch, D. 66 Durieux, M. 3: j, 36 Boman, C.-E. 150 Hines, J. E. 109 Kostkova, H. 32 Dushina, 0. V. 65 Bond, G. C. 67, 68 Hoare, J. P. 31 Kovylayev, A. D. 32 Borod’ko, Yu. G. 108 Hoekstra, H. R. 66 KraN, P. H. 53 Boudart, M. 111 Holland, H. B. 34 Krasikov, B. S. 108 Brady, D. G. 111 Eaborn, C. 70 Holleck, G. L. 67, 106 Krasilenko, N. P. 151 Bragin, 0. V. 154 Edeleanu, A. G. 109 Holleck, H. I49 Kren, E. 148 Brinkman, W. F. 149 Edshammer, L.-E. 107 Holmes, P. J. 71 Kudryavtsev, N. T. 67 Brodersen, K. 66 Efremenko, 0. A. 31 Horiuchi, S. 105 Brooks, C. R. 30 Elagina, N. V. 33 Hornfeldt, S. I07 Brown, C. K. 112 Ellison, P. J. 14 Hudson, J. B. 29 Landau, M. 151 Bryant, A. W. 65 Emel’yanova, G. A. 152 Huebner, R. P. I47 Langford,M. J. 151 Bncher, E. 149 Entscheva, M. 32 Hultgren, R. 65 Lawson, A. W. 149 Bucur, R. V. 147 Ermakova, S. I. 67 Hussey, A. S. 111 Lebedev, A. A. 35 Bugden, W. G. 65 Esaulov, N. P. 147 Hutcbinson, F. 32 Leu, E. 36 Buinova, L. N. I48 Esin. 0. A. 65 Hiittel, R. 66 L’Eplattenier, F. I 12, 150 Burch, R. 29, 106 Eurin, P 105 Hutton, M. E. 156 Lewis, F. A. 131

Platinum Metals Rev., 1970, 14, (4), 159-160 159 Page Page Page Page Lewis, J. 30 Okada, H. 68 Schindler, A. I. 147 Tkachenko, I. B. 149 Lien, T. R. 34 Okamura, T. 67 Schleitzer, E. 149 Tomashov, N. D. 35, 108 Lin, S.-S. 29 Olson, D. C. 32 Schrock, R. R. 155 Tret’yakov, I. I. 152 Lipshes, Z. 70 Orlova, F. A. 35 Schultz, R. G. 111 Trimm, D. L. 109 Littaner, E. L. 155 Ortelli, J. 148 Schultze, J. W. 3 1 Tsiovkin, Yu. N. 29 Lloyd, W. G. 70 Osborn, J. A. 155 Sebulsky, R. T. 67 Tsuji, J. 34,111 Lommel, J. M. 30 Otterson, D. A. 65, 106 Selman, G.L. 14,54,9_5? Turnbull, D. 30 Longworth, G. 65 Ozaki, A. I10 1 L4 Tylkina, M. A. 149 Lord, G. W. I08 Sergutkina, 0. R. 69 Tyurenkova, 0. A. 33, Shaffer, L. H. 66 110 Luberoff, B. J. 70 Padyukova, G. L. 150 Lund, W. 150 Shaimardanov, N. M. 151 Pagniet, J. 153 Shalaev, V. I. 149 Lyon, J. E. 155 Ugo, R. 111 Pan, B. Y. I(. 109 Shalya, V. V. 67 Ugodnikova, L. A. 29 Panchenkov, G. M. 151 Shavolina, N. V. 109 Uhara, M. 153 Pannetier, G. 69 Shcherev, G.I. 69 Maatman, R. W. 30 Pant, B. C. 70 Shekhobalova, V. 109 McDonald, D. 140 r. Panteleimonov, L. A. 29 Sherstyuk, N. I. 150 Van Bade, C. 148 McKee, D. W. 34 Parravano, G. 111 Shilova, A. 108 Van Den Sype, J. 147 Mackliet, C. A. 147 I(. Parshall, G. W. 154 Shimizu, S. 105 Van Loan, P. R. 35 Magat, L. M. 105 Parsons, J. L. 35,70, 155 Shipulina, L. P. 29 Vannice, M. A. 152 Maitrepierre, P. 106 Passabov, G. 32 Shlenskaya, V. I. 3 1 Van Peppen, J. F. 112, Majdic, M. 156 Paton, J. 68 Shuford, R. 112 155 Malashkin, V. V. 29 J. Pauleve, J. 105 Shvetsova, N. F. 70 Van Uitert, L. G. 118 Mal’tsev, A. N. 69, 154 Pearlstein, F. 67 Van Vucht, J. H. N.. 106 Mann, R. S. 33,34, 153 Siegel, S. 66 Peover, M. E. 150 Sigwart, C. 31 Vassiliev, Yu. B. 33 Marshall, C. 71 Pettov, K. 32 Silvestri, A. J. 33 Vedenyapin, A. A. 33, Martino, G. 149 152 Pickus, M. R. 66 Singh, P. P. 107 Masumoto, H. 64, 65 Vedernikov, M. V. 65 Podvyazkin, Yu. A. 69 Sinha, V. 64 Matthys, P. 112 Vehse, R. C. 148 Pozdnova, L. V. 154 Sivertsen, J. M. 148 Mayell, J. S. 31 Veselovskaya, 1. E. 108, Prapor, S. S. 29 Sklyarov, A. V. 152 Mellor, S. D. 34 I50 Pratt, J. P. 71 Smith, D. L. 105 Mencier, B. I 09 Vinogradov, S. N. 67 Pravoverov, N. L. 65 Smith, F. J. 88 Mercuri, R. A. 31 Ptak. L. D. 111 Vlasov, V. G. 109 Mikeg, F. 111,155 Smith, G. R. 32 Volodin, Yu. M. 151 Millington, J. P. 7 I Smith, G. V. 112 Volokhova, G. S. 151 Millstein, J. 150 Rafter, E. A. I10 Smith, R. J. 65, 106 Voorhics, A. 69 Minachev, Kh. M. 69 Raman, A. 107 Sokol’skaya, A. M. I52 Vostrikova, L. A. 107 Mizoguchi, T. 107 Randhava, S. S. 69 Sokol’skii, D. V. 33, 68 Modestova, V. N. 35 Rao, K. V. K. 66 Solov’eva, I. V, 154 Walker, E. 148 Moffat, J. 154 Ranb, E. 105, 107 Southworth, H. N. 28 wang, 30 Mohanty, A. K. 105 Reddy, G. S. 67 Speidel, T. 155 K. Watanabe, K. 105 Moiseev, I. I. 154 Rehmat, A. 69 Spence, J. T. 31 Moritani, I. 34, 35, 70 Reinacher, G. 107 Stewart, R. G. 147 Webster, D. E. 68 Weightman, R. F. 67 Moss, R. H. 108 Reinheimer, H. I54 Stoicovici, L. 147 Wells, P. B. 34 Moss, R. L. 110 Rennick, L. E. 155 Straws, B. 29 Wiese, U. 107 Muijhijk, R. 35, 36 Ritchie, A. W. 152 Strel’nikova, Zh. V. 152 Wilkinson, G. 112 Muller, F. A. 147 Robinson, K. K. 70 Sutton, E. A. 151 Williams, G. 106 Muller, 0. 30 Rogel’berg, I. L. 72 Svajgl, 0. 32 Winterbottom, M. Murray, G. T. 42 Romankiw, L. T. 32 Sultanov, N. A. 35 J. 68 Wisniewski. R. Mnrty, B. V. R. 147 Rony, P. R. 111 Svetlov, V. A. 31 65 Woodcock, R. F. 122 Mushak, P. 34 Roschel, E. 105, 107 Swanson, M. L. 64 Myers, H. P. 148 Rose, D. 71 Syutkina, V. I. 148 Roy, R. 30 Yagupsky, M. 112 Ruchkin, E. D. I07 Taimsalu, P. 67 Yamahc, T. 153 Ryden, W. D. 149 Yamaguchi, K. 47 Nadirov, N. K. 68 Rytvin, E. I. 29, 64 Tajbl, D. G. 69 Nagasawa, H. 64 Takahashi, H. 154 Yanchnk, B. N. 150 Nakamura, S. 153 Takenchi, Y. 111 Yasui, T. 153 Naro, P. A. 33 Sajus, L. 149 Tarasova, T. F. 72 Yatsimirskii, K. B. 71 Nevskaya, L. V. 65 Sale, F. R. 150 Tatamarov, M. A. 151 Yoshida, T. 153 Newman, R. J. 88 Samsonov, G. V. 149 Tawara, Y. 30 Nixon, A. C. 152 Sasaki, T. 107 Terekhov, G. I. 65 Zaidman, N. M. 67, 151 Nogi, T. 34 Sato, Y. 148 Thayer, J. S. 107 Zakumbaeva, G. D. 68, Norman, M. 30 Savitskii, E. M. 149 Thiele, G. 66 153 Novik, F. S. 29, 105, 147 Sawaya, S. 64, 65 Thomas, C. R. 29 Zapletal, V. 153 Novikov, I. I. 29, 64, 105, Schafer, H. 107 Thun, R. E. 71 Zasorin, A. P. 130 147 Scharf, G. 155 Tikhonova, L. P. 71 Zhuravlev, N. N. 147 Nowak, E. J. 68 Schiffrin, A. M. 149 Tilmes, R, 156 Zubenko, Yu. V. 147

Platinum Metals Rev., 1970, 14, (4) 160 SUBJECT INDEX TO VOLUME 14 a=abstract Page Catalysts (Contd) Page Palladium-Gold, films, dehydrogenation of Catalysts, combined, for NH3oxidation 130 HCOOH on, a 110 Indium, black, Hzadsorption on, a 69 oxidation of C,Hn on, a 110 black.,. hvdrogenation - of cvclodecenes Pdiamalgams, mechanisms of electrocatalysis on, a 154 in, a 68 complexes, with N and P donor ligdnds, a 154 Pd activated NiO/Al2OZ,reduction on, a 68 complexes, IrCI(CO)(PPh 3 I, Pd/Al,O,, dehydrocyclisation of desulphonation using, a 155 n-hexane on, a 68 H transfer on, a 111 complexes, IrH,(PPh,) 5, hydrogenation using, a 155 hydrogenation of isoprene on, a 33 complexes, IrX(CO)(PPh,),, X= H or hydrogenation of oils on, a 33 halogen, a 155 isotopic exchange in hydrocarbons on, a 69 hydrogenation of ethylacetylene on, a 155 reaction of n-butenes with H, and D, powder, hydrogenation of on, a 68 methylacetylene, a 33 vinyl acetate production on, a I53 powder, hydrogenation in HaSO, on, a 69 Pd/Al,O,-SO, hydrocracking of n-CsHIa Ir/A1,03, butene isomerisation over, a 34 and cyclohexane on, a 69 H, chemisorbed on, a 69 Pd/anilide, hydrogenation of unsaturated H transfer on, a Ill compounds on, a 33 hydrogenation of but-I-ene on, a 34 Pd/C, carbonylation of allylic ethers on, a 34 NHs absorption on, a 153 CarbOnybdtiOn of propargyl compounds Ir/C, hydrogenation of cyclo-olefins on, a 154 on, a 34 Ir/pumice, hydrogenation of ethylacetylene H2absorption on, a 153 on, a 153 hydrogenation of cyclo-olefins on, a 154 hydrogenation of methylacetylene on, a 33 hydrogenation of isoprene on, a 33 Ir/Si02,H transfer on, a 111 selective hydrogenation on, a 153 hydrogenation of neopentane on, a 111 vinylcyclohexene conversion on, a 110 NHJ absorption on, a 153 Pd/cellulose, hydrogenation of unsaturated oxidation of CaH, and C,H, on, a 110 acids on, a 153 Iridium-Platinum Oxides, hydrogenation Pd/clay, surface area and metal dispersion on, a 68 on, a 68 Osmium, black, H, adsorption on, a 69 Pd/polyacrylonitrile, hydrogenation of powder, hydrogenation in HaSOaon, a 69 unsaturated compounds on, a 33 Os/SiO,, hydrogenolysis of neopentane Pd/polyethyleneterephthalate,hydrogenation on, a 111 of unsaturated compounds on, a 33 Palladium, activity in nascent state, a 69 Pd/polyvinyl alcohol, activity and stability black, H, adsorption on, a 69 of, a 110 black, hydrogenation of cyclodecenes hydrogenation of on, a 154 dimethylethynylcarbinol on, a 110 black, hydrogenation in HSO, on, a 69 hydrogenation of unsaturated black, modification by Cdp+-of, a 68 compounds on, a 33 complexes, general features of, a 111 Pdiresin., hvdroeenation of Unsaturated acids complexes, x-olefin, oxidation of olefins on, a 153 by, a 154 PdjSiO?, H transfer on, a 111 complexes, with N and P donor hvdroeenation of isourene on. a 33 ligands, a 154 hjrdrogenolysis of neopentane on, a 1 11 complexes, 1,3-dichloro-2-hex- 1 -ene-4- oxidation of C,H, and C3Haon, a 110 (pzpyridine-N-oxide)Pd(ll), a 155 vinyl acetate production on, a 153 H ,sorption by, a 109 Pd/SiO,Al,O, He absorption on, a 153 Hg poisoning of C.H, hydrogenation on, a 68 Pd/zeolite, hexane isomerisation on, a 69 olefin complexes, for organic Palladium-Rhodium, films, oxidation of syntheses, a 111 C2H1on, a 110 oxidation of C2HIon, a 110 Platinum, activity in nascent state of, a 69 reaction of alcohols on, a 68 black, absorption of Ha and O2on, a 152 synthesis of vinyl acetate on, a 153 black, conversion of spiro-(4,4)-nonane Pd(OAc)2, aromatic substitution of on, a 33 olefins on, a 70 black, effect of ultrasonic field on, a 154 phenylation of lower olefins, a 34 black, Hz adsorption on, a 69 phenylation of olefins, a 35 black,.- hydrogenation - of cvclodecenes styrene reaction with monosubstituted on, a 154 benzenes, a 35 black, preparation and activity of, a 68 comdexes. for organic svthesis. a 111 Pd(acac),, carbonylation of allylic ethers, a 34 complexes; generd features of,a 111 PdCle, carbonylation of allylic ethers, a 34 complexes, with N and P donor carbonylation of propargyl compounds ligands, a 154 by,, a 34 complexes, (PPh8)sPtClz, chlorination of azobeiizene on, a Ill hydrogcnation using, a 155 decomposition of vinyl acetate on, a 11 1 crystalline size and orientation of, a 33 desulphonation using, a 155 H2sorption by, a 109 oxidation of olefins, a 70 hydrogenation of ethylacetylene on, a 153 styrene reaction with monosubstituted oxidation of CO on, a 152 benzenes, a 35 powder, hydrogenation of synthesis of esters on, a 111 methylacetylene on, a 33 terminal olefins reaction with reforming on, a 32, 33 diphenylacetylene, a 34 reforming, performance and trimerisation of acetylenes on, a 154 regeneration of, a 109 (PPhA?PdCI. hydrogenation using. a 155 Pt/amalgams, mechanism of A-allyl-Pd Chloiide, :socyanide reaction electrocatalysis in, a 68 with. a 154 Pt,/AlzOa,CsH, synthesis on, a 109 [CJ(M~~C.)P~CI]$, decomposition of, a 154 C,H,, conversion on, a 151

Platinum Metals Rev., 1970, 14, (4), 161-164 161 Catadysts, Pt/Al,O,, (Conid) Page Catalysts, RhCI(PPh&, (Contd) Page containing Mn, a 151 hydrogenation of unsaturated deactivation of, a 151 compounds on, a 70, 155 dehydrogenation of dicyclohexyl on, a 152 olefin hydrogeneration over, a 112, 155 dispersion of Pt on, a 151 oxidation of, (I 112 effect of- heat on, a 152 RhCI(CO)(PPh3)r, desulphonation on, a 155 hydrocracking of paraffinic crude on, a 109 hydroformylation on, a 70 H transfer on, a 111 RhH(CO)(PPh,),, inactivation of, a 112 hydrogenation of isoprene on, a 33 isomerisatinn on. a 112 isomerisationofC,H,andC,H1.on,a 151 RhCl[(cEH5)2(C10H8)PPH3)]3, hydrogenation isotopic exchange in hydrocarbons on, a 69 on, a /u low temperature isomerisation on, a 67 hydrogenation of nitro nature of “soluble” Pt on, u 67 compounds by, a 155 n-octane aromatisation on, a 109 preparation of, a 35 petroleum reforming on, a 151 Rh/AIAI,O,,H transfer on, a I11 reactions of butenes on, a 152 isomerisations of C,H... and reactions of CsH8and C.H, on, a 151 C4Hloon, a 151 Ptlasbestos, absorption of paraffins on, a 152 Rh/C, hydrogenation of cyclo-olefins on, a 154 production of steam on, a 151 RhjSiO,, H transfer on, a 111 Pt/C, hydrogenation of cyclo-olefins on, a 154 hydrogenolysis of neopentane on, a Ill hydrogenation of isoprene on, a 33 oxidation of C,HI and C,H, on, u 110 hydrogenation of oletins on 133 Rhodium-Palladium Oxides, kinetics of cyclodecane conversion on, a 33 hydrogenation on, a 68 molecular sieves, olefin hydrogenation Rhodium-Platinum Oxides, on, a 109 hydrogenation on, a 68 molecular sieves, shape selectivity of 133 Rh-AglSiO, hydrogenation on, a 33 reactions of cyclanes on, a 152 Rh-Sn Chloride complexes, hydride transfer Ptlclay, surfacc area and metal dispersion reaction on, a 155 on, a 68 Ruthenium, black, HI adsorption on, a 69 Pt/fine sand, oxidation of a-propanol on, a 67 complexes, general features of, a 111 Ptipumice, hydrogenation of ethylacetylene comulexes. with N and P donor 154 on, a 153 1igands;a 154 hydrogenation of methylacetylene on, a 33 powder, hydrogenation in H,SO, on, a 69 PtiSiO,, active centrcs in, a 152 Ru(acac)z, reduction of C8HsN0,with, a 112 H transfer on, a 111 Ru(CO),, reduction of C,HsNO, with, a 112 hydrogenation of isoprene on, a 33 RU,(CO),~,reduction of C,H,NO,, with, a 112 oxidation of C2H, and C,H, on, a 110 RuClp(PPha),, desulphonation using. a 155 PtjSiO %-Al2OS,metal-support RuH(OCOR)(PPha),, preparation and interactions of, a 109 properties of, a 71 Pt-CulSiO, H, chemisorption on, a I53 Ru/Al,OI, H transfer on, a 111 PtiSnheron. hvdroeenolvsis of neooentane hydrogenolysis of CzH,and C,H, on, a 111 on, a 69 Ptisupport, activity of, a 109 hydrogenolysis of n-C4Hloon, a 111 Pt+Pd. activitv of. a 109 methanation of CO on, a 69 Ft-Re, petrole& reforming on 86, 109 Ro/Celite, NHs synthesis on, a 110 U.O.P. R-16, Platforming with, a 151 Ru/SiO*,H transfer on, a Ill U.O.P. R-20, Platforming with, a I51 hydrogenolysis of neopentane on, a 11 1 Platinum-Rhodium, gauze, HCN oxidation of CsH, and C3Hson, a 110 synthesis on, a 109 Ruthenium-Palladium Oxides, gauze, HNO, synthesis on 61 hydrogenation on, a 68 Platinum-Rhodium-Palladium, gauze, Ruthenium-Rhodium Oxides, HNOa,synthesis on 130 hydrogenation on, a 68 PtO?,standardisation of, a 152 NaJrCI,, reduction of Ce(IV) by Hg,(N03)% Pt(II)-Sn(II) Chloride, hydrogenation on, a 71 of C,H with, a 70 TIIT, for pollution control 2, 108 H,PtCI,+(Et),SiH, hydrogenation with: a 70 purification of diesel exhausts by 78 Platinum Metals, absorption and Conductor Inks, Pd, Pt, Rh in, a 71 reactions of H, on, a 67 Corrosion, Pd-Ti, accumulation of Pd on, a 108 complexes, benzylic oxidation by, a 35 Pd-Ti, effect of 0,and TI ions on, a I08 decompositjon of HZOBon, a 34 Pd-Ti, for prevention of 41 hydrogenation of CIH, over, a 34 resistance of Pt-Ti to, a 108 isomerisation of ally1 alcohol on, a 34 Ru-Ti, effect of 0,and Ti ions on, a 108 oxidation of CHI on, a 34 Crucibles, Pt and Ir, for crystal growing 118 Rhodium, activity in nascent state of, o 69 Crystals, crucibles for growth of 118 black, catalytic properties of, CI 153 black, effect of ultrasonic field on, a 154 black, H, adsorption on, a 69 Diodes. Platinum-Silicon, resistance of, a 35 black, hydrogenation of cyclodecencs on, a I54 complexes, general features of, a 111 Electrical Contacts, Palladium-Silver, complexes, hydrogenation using, a 155 properties of 103 complexes, with N and P donor 154 Platinum, properties of 103 Iigands, a 154 Platinum Mctals, light duty 63 complexes, hydrogenation of Electrodeposition of, Iridium, survey of 93 cycloalkene on;a Ill Osmium. survey of 93 complexes, [RhH2X2L2]1, hydrogenation Palladium, survey of 93 of ketones by, a 155 from chloride electrolytes, a 108 isotopic exchange in hydrocarbons Palladium-Cobalt, internal stresses in, a 67 on, a 69 Palladium-Silver, alloy, a 32 RhCI,, polymerisation of Platinum, for fuel cell, a 71 butadiene on, a 111, 155 on Ir, a 32 RhCI(PPha), desulphonation on, a I55 on Ti, a 150 dissociation of, a 112 recent survey of 93 fluorenones from benzoic anhvdrides Rhodium, from molten NaCN, a 32 with, a 70 for Langmuir probes in rockets 123 hydrogenation of styrenes on, (I 112 recent survey of 93

Platinum Metals Rev., 1970, 14, (4) 162 Electrodeposition of Iridium (Cotztd) Page Palladium (Conrd) Page Ruthenium. a ._32.I 61-. H, solubility in thin films of, a 147 recent survey of 93 magnetisation of, a 147 Electrodes, Indium, intcraction with CO on, a 150 nuclear fission as source of 88 Irid_ium-Mercury, electrosorption of optical properties of, a 64, 148 0%on, a 150 resistor and conductor inks of, a 71 Palladium, electrochemical exchanae- single crystals of, a 107 current of, a 67 solubility of gases in, a 66 HI sorption by, a 150 sublimation under stress, a 64 polarisation of, a 31 thermal conductivity at high 64 Platinum, activation and roughening of, a 31 temperatures, a 64 adsorption of H1O on, a 30 Palladium Alloys, absorption of H, by, dimensionally stable 92 conference on 131 electrochemical exchange current of, a 67 Palladium-Aluminium, electrical resistance O*,diffusion through, n 31 of liquid, a 65 oxidation of N,H,-. on. , a 150 Palladium-Aluminium-Silver, structure wire, a ISI and solubility of, a 29 Platinum-Lead, bielectrodes, anodic Palladium-Barium, X-ray study of Pd,Ba, a 147 behaviour of. a I55 Palladium-Boron, Hain, a 106 Platinum-Mercury, electrosorntion of _I Palladium-Cobalt, electrical 0, on, a 150 resistance of, a 65, 106 Platinum-Rhodium, cyclic voltammetry of, a 31 specific heat studies of, a 148 for electrochemical acid generator. a 66 Palladium-Copper, electrical resistance of Platinum-Ruthenium, cyclic v&ammetiy liquid, a 65 of, a 31 magnetic properties of, a 29, 148 Platinum-Titanium, loss of Pt from, a 71 ordering in, a 148 Rhodium, electrochemical behaviour of, a 67 specific heat study of, a 148 Rhodium-Gold, cyclic vollammetry of, a 31 Palladium-Gadolinium, electrical Rhodium-Mercury, electrosorption of resistance of, u 149 OI on, a 150 lattice spacing and magnetic Rhodium-Platinum, cyclic voltammetry of, a 31 susceptibility of, a 30 for electrochemical acid generator, a 66 Palladium-Gold, effect of addition Ruthenium-Platinum, cyclic voltammetry of, a 3 1 elements on, a 70 RuO,/Ti, dimensionally stable 92 electrical resistaiice in Haof, a 65 Electroless Plating of, Palladium 67 terminations, a 70 Palladium-Gold-Iron, Mossbauer study of, a 65 Fucl Cells, electrodeposition of Pl for 71 Palladium-Gold-Tungsten, structure and properties of, a 65 Glass, Pt inclusions in 122 Palladium-Iron, electrical resistance of liquid, a 65 Hydrogen Diffusion, in a-Pd, a 29 fine Darticle nreparation, a 30 Hypochlorite Cells, Pt/Ti electrodes in, loss of Pt Palladium-Manganese, electrical resistance from. a 71 of liquid, a 65 ordering effects of, a I48 Iridium, crucibles for crystal growing 1 I8 soecific heat studies of. a 148 strength and ductility of 60 Palla$um-Nickel, electrical resistance Iridium Alloys, Iridium-Carbon, composition of liquid, a 65 of, a 66 heat capacity, effect of disordering on, a 30 Iridium-Hafnium, structure of, a 30 moments of dilute Fe In, a 48 Iridium-Iron, magnetic properties of, a 107 thermal cxpansion of, a 64 Iridium-Nickel, properties of, a 149 Palladium-Nickel;Phosphorus, structure of, a 107 electrical reslstivlty of, a 106 Iridium-Rhenium-Tungsten, Palladium-Platinum, moments of composition of, a 149 dilute Fe in, a 48 Iridium Complexes, containing N, synthesis Palladium-Rhenium, activated sinkring of, a 65 and properties of, a 149 Palladium-Rhodium, elastic properties of, a 148 polynuclear nitrido-complexes, a 108 magnetic properties of, a 148 Iridium Compounds, reaction with refractory Palladium-Rhodium-Silver, moments of carbides and borides, a 31 148 Iridium Dioxide, electrical transport dilute Fe in, a nroperties of, a 149 Palladium-Scandium, lattice spacing and thermal expansion of, a 66 magnetic susceptibility of, a 30 Palladium-Silicon, glasses, a 30 Matthey Bishop, history of 140 Palladium-Silver. conductor terminations Microelectronics, high purity Pt for 42 of, a 71 elastic properties of, a 148 electrical contacts of 103 Nitric Acid, catalyst costs for production of 61 HZin, a 29, 106 magnetic properties of, a 148 Osmium, activator for W sintering, a 149 resistor pastes 53 Osmium Complexes, containing N, synthesis thermodynamic properties of, a 65 and properties of, a 149 thick film conductors of, a 112 polynuclear nitrido-complexes, a 108 Palladium-Silver-Aluminium, structure Osmium Compounds, carbonyl, a 150 and solubility of, a 29 150 Osmium Dioxide, crystal structure of, a Palladium-Silver-Boron, absorption of HI in, a 106 Palladium, activator for W sintering, a 149 Palladium-Tin, thermodynamic properties coating Ti with 47 of, a 65 29 dissociation energy of Pd,, a Palladium-Titanium, corrosion of, a 35, 108 electrical resistance in Hzof, a 65 Hzpick-up in, a 35 electrical resistivity of PdH,,, a 106 martensitic transformations in, a 106 electrochemical dissolution in chlorinated HC1, a 32 Palladium-Uranium, thermoelectric films, H absorption on, a 64 properties of, a 65 H, absorotionabsorption in.in, a 65, 106 Palladium-Zirconium, lattice spacing and H2Hz diffusion in, a 29, 64, 106)6 magnetic susceptibility of, a 30

Platinum Metals Rev., 1970, 14, (4) 163 t ’age Resistance Thermometers, (Cod) I ’age Palladium Complexes, olefin, a 30 Pt, for lunar heat flow 85 reactions with organic compounds, a 66 Resistors, RuO,, thick film glaze, a 35 unsaturated hydrocarbon compounds 62 Resistor Inks, Pd in, a 71 Palladium Compounds, K,PdCIs, NQR study of, a 66 Resistor Pastes, Pd-Ag, effect of firing on Pen Tim. Pt-Ru for. a 66 performance 53 Petrol&& Refming,‘Pt/Al,O, catalyst for, o 151 Rhodium, activator for W sintering, a 149 U.O.P. catalvsts for. a 151 conductor inks, a 70 Platinum, beam.leads of,’ a 156 deep drawing of, a 107 conductor inks of, a 71 high temperature creep of, a 149 crucibles for crystal growing 118 nuclear fission products, sues of 88 clectrical contacts of 103 single crystals of, a I07 inclusions in laser glass 122 Rhodium Alloys, Rhodium-Carbon, purification of 42 composition of, a 66 reactions with refractory oxides 54, 95, I24 Rhodium-Hafnium, structure of HfrRh,, a 30 recovery from deformation, a 64 Rhodium-Iron, thermodynamics of spinning band 87 transition in, a 30 solubility of gases in. a 66 sublimation under stress, a 64 Rhodium-Neodymium, phase diagram of, u 107 thermal expansion of, a 147 Rhodium-Nickel, magnetic properties of, a 149 vapour pressure of liquid, a 29 structure of, a 107 Platinum Alloys, Platinum-Aluminium, 124 Rhodium-Palladium, elastic properties of, a 148 composition of I24 magnetic properties of, n 148 Platinum-Antimony, structure of 29 Rhodium-Palladium-Silver, moments of Platinum-Barium, X-ray and electron dilute Fe in, a 148 microscope studies of, a 147 Rhodium-Platinum, creep in, a 29, 105, 147 Platinum-Chromium, resist ancc immersion heater of, a 150 minimum in, a 64 Matthiessen’s rule in, a 147 thermodynamic properties of, a 105 sublimation under stress, a 64 Platinum-Cobalt, internal friction in, a 147 wire for furnace work tube, a 108 ordering of, a 105 Rhodium-Titanium, structure of Ti,Rh,, a 30 specific heat studies of, a 148 Rhodium Complexes, chloride, a 31 Platinum-Cobalt-Iron, magnetic containing N, synthesis and properties properties and microstructure of, (1 105 of, a 149 Platinum-Copper-Zinc, structure of, II 147 olefin, a 30 Platinum-Iron, coercivity and structure pyridine, redox behaviour and antibacterial of, a 105 activity of 50 hardening in dcntal golds, a 105 Rh [(CsHa)J’14and Rh [(C,Hs),PCHslr, Platinum-Magnesium, composition of 124 electrochemical preparation of, a 32 Platinum-Manganese-Tin, structiire and magnetic properties of, a 105 Rhodium Compounds, reaction with refractory Platinum-Molybdenum-Rhenium, structure carbides and borides, a 31 and superconductivity of, a 105 Rhodium Sesquioxide, free cnthalpy of Platinum-Nickel, magnetic properties of, a 64 formation of, a 107 specific heat and resistivity of, a 147 Rustenberg, electric smelter at 48 thermal expansion of, a 64 Platinum-Palladium. moments of Ruthenium, activator for W sintering, a 149 dilute Fe in, a I48 solubility of gases in, a 66 Platinum-Rhodium, creep in, a 29, 105, 147 thick films of, a 71 immersion heater. of. a 150 Ruthenium Alloys, Ruthenium-Platinum, Matthiessen’s rule in. a 147 for pen tips, a 66 sublimation under stress, a 64 Ruthenium-Titanium, corrosion of, a 108 wire for furnace tube work, a 108 Rut henium-Uranium-Carbon, Platinum-Ruthenium, for pen tips, a 66 composition of, a 149 Platinum-Silicon, resistance of, a 35 Ruthenium Complexes, a 31, 108, 149 Platinum-Tellurium, structure of, a 29 Platinum-Thorium, composition of I24 Ruthenium Oxide, a 35, 149, 150 Platinum-Tin, structure of, a 29 Platinum-Titanium, martensitic Surface Coatings, Pd, activation of plastics transformations in, a 106 for, a 32 Platinum-Zirconium, composition of 124 Pt, sputter deposition for beam leads, a 156 Platinum Chloride, preparation of, a 107 Pt metals, for stereoscan specimens 139 Platinum Complexes, general survey of, a I07 olefin, a 30 unsaturated hydrocarbon 62 Temperature Measurement, at low cis-[PtCl %(MeC(:O)CH EMeCH,)I, a 66 temperature, a 35 Platinum Compounds, HpPtCIe,a 30 definition of scale, a 35 KBPtCI., NQR study of, a 66 Thermocouples, Baker 417, (Rh-Pt :Pd-Au), PtSeTe, PtSSe, PtSTe, a 107 properties of, a 72 Platinum Iodide, crystal structure of, a 66 Au-Pd-Pt:Rh-Pt, a 156 Platinum Metals, electrical Contacts of 63 Palladium, alloys of, properties of, a 72 fission product, uses of 88 Pallador I, properties of, a 72 single crystals of, a I07 Pallaplat, properties of, a 72 Platinum Metals Alloys, with Al, X-ray PlP (Tr-Pt :Pd), properties of, a 72 studies of, n 107 Platinel I and 11, thermoelectric Platinum Oxides, P-PtOa, crystal structure of, u 66 properties of, a 72 CuL-xPtKOand CuPt,Oa, synthesis and Pt:Rh-Pt, u 36, 150 structure of. a 30 for furnace control. a I08 for incinerator control. a 46 TB 19-29! (Rh-Pt :Pt-Pd-Au), Resistance Thermometers, Pt, calibration of, a 71 properties of, a 72 Pt, Callendar’s equations for, a 71 Pt, temperature scale of, a 35 Thick-filmcircuits, Pd, Pt, Rh in, a 71 Pt, comparison with vapour pressure 36 Ru for, a 71 thermometers, a 36 Thick-film Conductors, Pd-Ag, a 112

Platinum Metals Rev., 1970, 14, (4) 164