E. I. Klabunovskii

Enantioselective hydrogenation of the C=O bond at Raney cobalt catalyst modified with optically active acids

Conclusions1.The enantioselective activity of Raney cobalt catalysts obtained from cobalt-aluminum alloys with various compositions and modified by optically active tartaric acid and amino acids was investigated.2.It was established that the optical yield during hydrogenation of ethyl acetoacetate at cobalt catalysts modified with amino acids bears an inverse relationship to the stability constants of the cobalt-amino acid complex.

Effect of temperature on the basicity of certain aliphatic-aromatic amino alcohols

Ionization constants were obtained of 14 amino alcohols and one tertiary amine in 50% ethanol in the range of 10–25° and thermodynamic characteristics of the ionization process of the investigated ammonium ions were calculated.

Investigation of the stereospecific hydrogenation of D-Fructose on Raney nickel using the method of mathematical planning of the experiment

The hydrogenation of fructose on a Raney Ni catalyst, modified with optically active tartaric and glutamic acids, was studied using the method of mathematical experimental planning. The conditions under which the yield of sorbitol reaches 65.7% were found.

Catalytic hydrogenation of furfurylideneacetone

The stepwise character of the hydrogenation of furfurylideneacetone on a Raney nickel catalyst at 50° C and atmospheric pressure was investigated. It is shown that the intermediate-1-(α-furyl)-3-butanone — is primarily hydrogenated to 1-(α-tetrahydrofuryl)-3-butanone.

Ligand effect in dissymmetric Cu-Ru and Cu-Pd catalysts

ConclusionsFor 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.

Catalytic hydrogenation of ethyl α-acetylamino-β-ketobutyrate on modified metal catalysts

Conclusions1.We have prepared a skeletal Cu-Pd catalyst modified with tartaric acid, on which there is 100% selectivity in the hydrogenation of ethyl α-acetylamino-β-ketobutyrate with a yield of N-acetyl-allo-threonine ethyl ester of about 90%.2.It is shown that the nature of the metal phase of the catalysts has an effect on their activity, selectivity, and diastereoselectivity in this process.

Asymmetric hydrogenation of acetylace tonates on raney nickel catalyst

Conclusions1.Hydrogenation of the acetylacetonates of Ni, Co, Cu, and Zn at atmospheric pressure and at 100 atm both on Ni and on NiM proceeded at a lower rate than the hydrogenation of pure acetylacetone. The rate of hydrogenation grew along the series of acetylacetonates Co < Zn ≤ Ni < Cu (Ni) and Co < Zn ≤ Cu < Ni (NiM).2.Hydrogenation of acetylacetonates on a nickel catalyst modified with (+)-tartaric acid led to the formation of optically active products.

Preparation of D-sorbitol from enzymic hydrolyzates of starch

As is known crystalline glucose is used in the manufacture of D-sorbitol. However, a more economic method is the direct hydrogenation of polysaccharides of vegetable origin or their hydrolyzates [1-7]. Such routes reduce the cost of sorbitol manufacture and exclude the series of operations of the preparation of crystalline glucose. Starting from the concept of manufacturing glucose by enzymic hydrolysis of starch we have investigated the possibility of substituting enzymic hydrolyzates for crystalline glucose in the manufacture of D-sorbitol.

Asymmetric hydrogenation of acetoacetic ester on raney cobalt and copper catalysts modified with D-(+)-tartaric acid

1. n nOn Raney Cu and Co catalysts modified with D-(+)-tartaric acid acetoacetic ester is hydrogenated asymmetrically. n n n n n2. n nThe optical yield of (-)-ethyl-3-hydroxybutyrate depends on the nature of the catalyst and the experimental conditions: on Cu catalyst the optical yield reaches 20–24% and is close to the optical yield obtained on modified Ni catalyst: on Co catalyst the optical yield is considerably less (2–8%). With increase in the quantity of catalyst the optical yield on these catalysts passes through a maximum.

Mutarotation of β-D-arabinose in the presence of aliphatic-aromatic amino alcohols as catalysts

1. n nThe rate constants of the mutarotation ofβ-D-arabinose in 50% aqueous ethanol in the presence of the investigated catalysts obey the Bronsted function withβ = 0.84±0.01 at 20°. n n n n n2. n nThe thermodynamic parameters of the activation of the mutarotation ofβ-D-arabinose under the action of the investigated catalysts are related by an isokinetic function (β = 250 ± 2K).