SYNTHESIS OF HIGHLY PURE L-3-HYDROXY-γ-BUTYROLACTONE FROM L-MALIC ACID AND L-ALANINOL FROM ALANINE BY SELECTIVE HYDROGENATION OVER Pt-ReO_X/C CATALYST

摘要

Selective hydrogenation of L-malic acid and L-alanine aqueous solutions, respectively, to L-3-hydroxy-γ-butyrolactone and L-alaninol on a highly dispersed Pt-ReO_x/C catalyst was studied under mild conditions (T = 75℃-110℃). In the low-temperature region, where racemization proceeds by two to three orders of magnitude more slowly than that of hydrogenation, we obtained a chemically (lactone yield > 98%) and optically pure cyclic ester with an enantiomeric excess ee > 99%. In an acid medium (pH 99%.