High-performance Pt catalysts supported on amine-functionalized silica for enantioselective hydrogenation of alpha-keto ester

Abstract

Heterogeneous enantioselective catalysis is an attractive approach to produce enantiopure chemicals, which are key intermediates for pharmaceutical products. Herein, mesocellular silica foams (MCFs) functionalized by primary, secondary, and tertiary amine groups were used as supports for Pt nanoparticles. The catalytic performances of the Pt/amine-functionalized MCFs were evaluated for the enantioselective hydrogenation of methyl pyruvate in the presence of cinchonidine. Compared to Pt/MCF, the Pt/amine-functionalized MCFs exhibited enhanced activity and enantioselectivity. Particularly, 0.5 wt% Pt/NH2MCF showed a superior performance than 5 wt% Pt/Al2O3, a highly efficient catalyst in the enantioselective hydrogenation of a-keto esters, despite a 10 times lower Pt loading. Furthermore, the Pt/NH2-MCF yielded 100% conversion and 96% ee at 0.1 MPa H-2 pressure during nine successive cycles, thus showing high reusability. The excellent performance of the Pt/amine-functionalized MCFs is attributed to the formation of electron-deficient Pt species through strong interactions between the Pt nanoparticles and amine groups. (C) 2021 Elsevier Inc. All rights reserved.