Experimental and Model Study on Enantioselective Extraction of Phenylglycine Enantiomers with BINAP–Metal Complexes

Enantioselective extraction of phenylglycine (PHG) enantiomers with (S)-BINAP–metal complexes as chiral selector was investigated. A reactive extraction model was established to interpret the experimental data. The complexation equilibrium constants and other important parameters required by the model were determined experimentally. The extraction system shows good selectivity toward PHG enantiomers. The complex [(S)-BINAP(CH3CN)Cu][PF6] (BINAP–Cu) exhibits the highest selectivity among the selectors studied, which is dissolved in the organic phase and preferentially extracts l-PHG from aqueous phase. Efficiency of extraction depends, often strongly, on a number of process variables, including types of organic solvents and metal precursors, concentration of selector, pH, and temperature. The model quantitatively predicts extraction performance as a function of key operating parameters, providing a simple computational approach to process optimization. The model was verified experimentally with excellent results.