Hydrogenation of aldehydes and ketones catalyzed by zeolite-supported polyvinyl alcohol amino acid platinum complex

Zeolite-supported polyvinyl alcohol-amino acid (alanine, proline, glutamine , leucine or lysine)-platinum complexes (Zeo-PVA-AA-Pt) have been prepared by a very simple method and have been found to catalyze the hydrogenation o f some aldehydes and ketones such as hexanal, benzaldehyde, cyclohexanone, 2-pentanone, methyl acetoacetate, ethyl acetoacetate, 2,4-pentandione to 1- hexanol, cyclohexylmethanol, cyclohexanol, 2-pentanol, methyl 3-hydroxybuty rate, ethyl 3-hydroxybutyrate and 2,4-pentandiol, respectively, at 55 degre es C and under an atmospheric hydrogen pressure. In several cases, the yiel d or selectivity amounted to 100%. Such catalysts were very stable in the h ydrogenation, and could be reused several times without any remarkable chan ge in the catalytic activity. The catalytic activity was greatly affected b y molar ratios of monomer unit of polyvinyl alcohol to amino acid, amino ac id to Pt in the complex, and the nature of the amino acids and solvent used in hydrogenation. In the hydrogenation of methyl acetoacetate to methyl 3-hydroxybutyrate, a small amount of optical active product was obtained. This result suggested that more effective catalysts for asymmetric hydrogenation may be found fro m such simple polymer-amino acid-metal complexes by selecting the proper am ino acid and polymer. (C) 1999 John Wiley & Sons, Ltd.