Collect. Czech. Chem. Commun.
2005, 70, 1642-1652
https://doi.org/10.1135/cccc20051642
In situ Chiral Modification of Nickel Catalysts for Enantioselective Hydrogenation of Methyl Acetoacetate
Lukáš Bartek, Petr Klusoň and Libor Červený*
Department of Organic Technology, Institute of Chemical Technology, Prague, Technická 5, 166 28 Prague 6, Czech Republic
Abstract
Chiral modifications of SiO2-supported and Raney nickel catalysts were studied. The catalysts were employed in asymmetric hydrogenation of methyl acetoacetate (MAA) to (R)- and (S)-enantiomers of methyl 3-hydroxybutanoate. The effects of modification parameters such as type and concentration of modifier; presence of a co-modifier and other additives, pH of modification solution on the enantioselectivity of MAA hydrogenation were discussed. Characteristic features of the in situ modification of Ni/SiO2 were also evaluated and the results obtained were compared with the conventional (premodification) approach. Parameters for the conventional and in situ methods were optimised in a series of experiments for both types of catalysts. The in situ modified Ni/SiO2 was found specifically suitable for repeated use due to virtually no decrease in selectivity and activity.
Keywords: Enantioselective catalytic hydrogenation; In situ modification; Tartaric acid modified Raney nickel catalyst; Sol-gel; Asymmetric reductions; Heterogeneous catalysis.
References: 49 live references.
