The Optical Resolution of Mandelic Acid

A process was disclosed for resolving mandelic acid using optically active phenylglycine butyl ester or its hydrochloride. The yield and optical purity of S-(+)-mandelic are 90.1% and 66.73% for At the same time, The yield and optical purity R-(-)-mandelic acid are 98.9% and 32% respectively. Additionally, a general synthetic method of phenylglycine butyl ester and its hydrochloride was disclosed.