Agency of Industrial Science and Technology

Sumi Imai

Shuichi Niwa

Fujio Mizukami

Makoto Toba

Yoshio Orito

A mixture of a cyclodextrin and an alkoxy silane compound, e.g., tetraethoxy silane, is admixed with water and an acidic or alkaline catalyst, e.g., acetic acid, to effect ligand exchange and hydrolysis of the alkoxy silane followed by gelation into a gelled mass which is dried and, preferably, leached with water to remove excess of the cyclodextrin. The thus obtained gelled material is a composite having a structure in which the cyclodextrin molecules are incorporated into the matrix of amorphous silica presumably by forming Si-O-C linkages. The composite has characteristics as a combination of the properties of both of the component materials and can expand the applicability of the materials, for example, as a carrier of catalysts and immobilized enzymes, absorbent and adsorbent and so on.

Cyclodextrin-silica composite and a method for the preparation thereof

A method for the asymmetric hydrogenation of .alpha.-ketoesters which comprises subjecting an .alpha.-ketoester containing an .alpha.-ketoester grouping of the formula: --CO--COO-- to assymmetric hydrogenation in the presence of a platinum-alumina catalyst modified with a solution of a cinchona-alkaloid.

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Yatabe, Japan

Sumi Imai