Nickel arsenide hydrogenation

Industrial processes were developed for the selective partial hydrogenation of 4-vinylcyclohexene with Ni catalysts exhibiting minimized isomerization activity in the presence of additives298,299. For example, supported nickel arsenides prepared by reducing nickel arsenate with NaBFLt display high selectivity in the formation of 4-ethylcyclohexene (96% selectivity at 96% conversion on Ni-As-Al2C>3, 398 K, 25 atm H2, acetone additive). 

The hydrogenation of 4-vinylcyclohexene (46) to 4-ethylcyclohexene (47) was also reported to take place over a supported nickel arsenide, Ni-As(B), which was prepared by the sodium borohydride reduction of nickel arsenate supported on either silica 2,83 or alumina. " These catalysts, however, fimction best in the presence of additives. When the reaction was run in pentane at 125 C and 25 atmospheres of hydrogen in the presence of a small amount of acetone, the product mixture at 96% conversion was 96% 4-ethylcyclohexene (47) and 4% ethylcyclohexane (48). No isomeric olefins were detected. " ... 

Wohler obtained phosphorus by strongly heating a mixture of sand and bone-black (calcium phosphate and carbon) — the modern process, now carried out in the electric furnace. He prepared artificial nickel arsenide and worked on the separation of iridium and osmium in a pound of platinum residues given him by Dumas on a visit to Paris in 1833. A supposed silver suboxide, Ag40, prepared by Wohler by the action of caustic potash solution on a supposed subcitrate made by heating silver citrate in hydrogen at 100°, was not analysed and was probably a mixture of silver and silver oxide AggO the red colour of the solution of the subcitrate was probably due to colloidal silver. ... 

Nickel Di-arsenide, NiAs2, occurs in Nature as chloanthite and ram-melsbergite (p. 12). It may be prepared by heating either of the two previously described arsenides with arsenic in an atmosphere of hydrogen at decreasing temperatures the arsenic is absorbed and the di-arsenide forms as a grey powder as the temperature falls below 100° C.2... 

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