Enhanced enantioselectivity in the heterogeneous catalytic hydrogenation of acetoacetate esters into the corresponding 3-hydroxybutyrates using commercial nickel powder

Heterogeneous catalytic hydrogenation of acetoacetic acid esters over tartaric acid/NaBr-modified Ni powder was determined to be a critical function of the steric bulk of the ester moiety to afford quantitatively 3-hydroxybutyrate in 94% enantiomeric excess when ethyl and i-butyl esters are used, providing a facile route to optically active 3-hydroxybutyrates.     

Asymmetric electrocarboxylation of 1-phenylethyl chloride catalyzed by electrogenerated chiral [CoI(salen)]− complex

The feasibility of asymmetric electrocarboxylation of 1-phenylethyl chloride catalyzed by the electrogenerated chiral [Co^I(salen)]⁻ complex has been investigated for the first time. Using this system, optically active 2-phenylpropionic acid in 37% yield and 83% ee is synthesized from 1-phenylethyl chloride and CO₂. The electrochemical behavior of the catalyst and the optimization of synthesis conditions are discussed. This study provides a new procedure for the asymmetric synthesis of a chiral compound and expands the applications of chiral Co^II(salen) in the electrochemical asymmetric fixation of CO₂.     

A M?ssbauer spectroscopic study on the action of Ce in the catalyst for dehydrogenation of etylbenzene to styrene

Two series of Fe-K catalysts for dehydrogenation of ethylbenzene to styrene were prepared with different amounts and different compounds of the additional element Ce. M?ssbauer spectroscopy has been used to determine the Fe compound in the catalyst and to investigate the effect of Ce. The catalytic properties of the catalysts have also been measured. The results show that the element Ce in the catalyst is favorable to form the predecessor of the catalytic active phase, the compound KFe₁₁O₁₇ and that the optimal percentage of CeO₂ is 8%～15% in the catalyst which is favorable to the formation of KFe₁₁O₁₇ and to get better catalytic properties.     

Bi-Hamiltonian structure of multi-component Novikov equation

In this paper, we present the multi-component Novikov equation and derive it's bi-Hamiltonian structure.