Modification of supported Pd catalysts by alkalic salts in the selective racemization and dynamic kinetic resolution of primary amines

Supported Pd nanoparticles (PdNPs) were modified with various alkalic salts by incipient wetness impregnation method. The effect of the salts on the catalytic activity and selectivity behavior of Pd catalysts for the racemization of (S)-1-phenylethylamine was investigated. The presence of alkalic salts can greatly enhance the selectivity of Pd catalysts, without significantly decreasing the catalytic activity. This modification method is suitable for PdNPs supported on various supports, such as micro/mesoporous silica and activated carbon. Combined with the immobilized lipases (Novozyme 435), this catalyst system can efficiently catalyze the dynamic kinetic resolution (DKR) of 1-phenylethylamine with yield and enantioselectivity up to 97% and 99%, respectively.