Abstract: Hydrogenation-dehydrogenation of suitable feedstock is provided wherein such feedstock is subjected to hydrogenation-dehydrogenation conditions in the presence of a catalytic amount of a solid containing, at least in part, a synthetic amorphous solid prepared by hydrolyzing and polymerizing in the presence of water a silane having the formula R(Si)X.sub.3, wherein R is a nonhydrolyzable organic group, X is a hydrolyzable group and (Si) is selected from the group consisting of ##STR1## and calcining the polymerized product, said silane being admixed with a second compound, R'.sub.n MY.sub.m, wherein R' is selected from the group consisting of the same groups as R, Y is selected from the group consisting of the same groups as X and oxygen, M is at least one member selected from the group consisting of the elements of Groups IIIA, IVA, VA, IVB, VB, VIB, VIIB and VIII of the Periodic Table, m is any number greater than 0 and up to 8 and n is from 0 to any number less than 8.

Abstract: Composite product, useful notably as a catalyst, comprising a coordination complex of a metal, notably of a transition metal, fixed to a support, wherein this support is formed of a solid mineral material, insoluble in organic solvets, and is covered at least partly by a polysiloxane, on which the coordinates of these complexes are grafted. This catalyst is stable in gaseous as well as in liquid media, and is useful for the hydrogenation of olefins in homogeneous and heterogeneous phases as well.

Abstract: Hexakis(phosphite ester)chromiums of the formulaCr[P(OR).sub.3 ].sub.6are prepared by chromium-atom evaporation and cocondensation with a phosphite ester. Dihydridopentakis(phosphite ester)chromiums of the formulaCrH.sub.2 [P(OR).sub.3 ].sub.5are prepared by hydrogenation of the corresponding hexakis(phosphite ester)chromiums. Both the hexakis- and the dihydridopentakis(phosphite ester)chromiums are useful as hydrogenation catalysts.

Abstract: Aliphatic unsaturated material or compounds are hydrogenated. Specifically, unsaturated dinitrile, e.g., 5-methyl-4-nonenedinitrile, 2,4-dimethyl-4-octenedinitrile, 2,4-dimethyl-3-octenedinitrile, 2,4,6-trimethyl-3-heptenedinitrile, 5-methylenenonanedinitrile, 2-methyl-4-methyleneoctanedinitrile and 2,6-dimethyl-4-methyleneheptanedinitrile, in a mixture resulting from reaction of isobutylene and acrylonitrile are hydrogenated in presence of a palladium hydrogenation catalyst disposed on an active alumina support also having disposed thereon an adjuvant selected from cerium, thorium, manganese, praseodymium, neodymium and samarium. A specific combination of adjuvants namely cerium together with lanthanum was found to improve the hydrogenation at low levels of cerium.Other aliphatic compounds which can be hydrogenated according to the invention include among others ethylene, 1,3-butadiene, cinnamic acid, 5-methyl-4-nonenedicarboxylic acid, diethyl 5-methylene-nonanedicarboxylate, etc.