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The influence of the metal content on the support, the conditions of the preparation of the catalysts, and the reaction conditions on the enantioselectivity of the liquid-phase hydrogenation reaction of ethyl acetoacetate in the presence of Ni and Ni-Co catalysts supported on Al2O3 and SiO2, and modified by RR(+)-tartaric acid, was investigated. The maximal optical yield (66–76%) was obtained for the 20% Ni/Al2O3 catalyst.

Thermal-desorption and isotope methods were used to investigate the state of hydrogen found on the surface of ruthenium framework catalysts. The possibility of the migration of chemisorbed hydrogen from the ruthenium was demonstrated.

Conclusions:

A study was carried out on the effect of the nature of the catalysts, additives, and solvents on the stereoselectivity of the liquid-phase hydrogenation of an equilibrium menthone-isomenthone mixture to give menthols. Neoisomenthol, which is the least stable of all the menthol isomers, was predominantly formed on a cobalt catalyst modified by (+)-tartaric acid in ethyl acetate at 130°C and 10 MPa.

The correlation between the asymmetrizing and catalytic activities of ruthenium catalysts of different origins has been studied. The preparation of the catalyst and the nature of the support have been shown to have a considerable effect on the specific activity of the catalyst and its asymmetrizing ability.

Conclusions 1.Using adsorption, thermal desorption, and isotopic methods the authors have investigated the state of hydrogen present on the surface of Ru/Al2O3, Ru/SiO2, and Ru black catalysts.2.Hydrogen can be adsorbed very strongly on the surface of Ru catalysts, and removed only at elevated temperatures. The amount of strongly adsorbed hydrogen sharply increases in going from Ru black to deposited catalysts.3.Hydrogen adsorbed on Ru can spread over the carrier surface and take part in exchange with the carrier OH groups.

1.The inhibiting effect of the complex [Co(DH)2PyC1] on the initiated oxidation of cumene was established. It was demonstrated that the inhibition is due to interaction of the complex with peroxide radicals.2.Two alternative schemes of the action of the complex on the chain reaction of oxidation were considered, and a quantitative comparison of the experimental results with the scheme was made. The values of the rate constants of the individual steps of the reactions were calculated.

LinC60fullendes were prepared by high-pressure solid-state reactions and characterized by IR spectroscopy and x-ray diffraction. The results are interpreted in terms of a sequence of phase transformations induced by Li incorporation. At low Li contents, 2

For Raney Cu-Ru and Cu-Pd catalysts non-additive changes in the strength of the catalyst-hydrogen bond and in the catalytic activity and enantioselectivity were found to occur with changing composition, indicating the presence of a ligand effect in these systems.

1.Bimetallic powdered nickel-cobalt catalysts differing in composition and modified by RR-(+)-tartaric acid were studied in the asymmetric hydrogenation of ethyl acetoacetate.2.The optical yield of this reaction is increased to 54% with an increase in the nickel content in the Ni-Co catalyst to 90% and is 60–65% for the nickel catalyst.

1.The properties of Raney nickel catalysts modified by (+)-tartaric acid and active in enantioselective hydrogenation of ethyl acetoacetate depend on the chemcial and phase compositions of the starting Ni-Al alloys.2.A decrease of the Ni content in the Ni-Al alloy specimens which corresponds to an increase of the fraction of the NiAl3 intermetallic compound in them contributes to an increase of the catalytic activity and enantioselectivity of the action of the obtained catalysts.

1.Skeletal copper-ruthenium catalysts are composed of copper, ruthenium, bayerite, and gibbsite phases.2.The change curves of the copper-ruthenium catalysts were taken, and from them were determined the specific surface areas of the ruthenium phases and the average size of the ruthenium crystallites.3.A complex relationship was found to exist between the dispersity of ruthenium and its amount in a mixed catalyst.

The complexes of Co, Ni, Fe, and Cu with dimethyl- and diphenylglyoxime inhibit the initiated oxidation of cumene by reacting with the peroxide radicals.

Enantioselective hydrogenation of ethyl acetoacetate was carried out for the first time on unsupported 1:1 Cu-Ni catalysts obtained by precipitation. The highest optical yield (50%) was obtained with a catalyst obtained by reduction of oxides at 250°C in a 1:10 H2:N2 atmosphere.

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Skeletal ruthenium catalyst, modified with D-(+)-tartaric acid, leads to the asymmetric hydrogenation of the carbonyl group in acetoacetic ester.