Enantioselective Extraction of Racemic Mandelic Acid by Di(2‐ethylhexyl) Phosphoric Acid and Tartaric Acid Derivatives as Mixed Complex Chiral Selectors

The distribution behavior of mandelic acid (MA) enantiomers was examined in a two‐phase system containing di(2‐ethylhexyl) phosphoric acid (D2EHPA) with two tartaric acid derivatives as complex chiral selectors in n‐octanol. Factors affecting the extraction were investigated, including the structure and concentration of tartaric acid as well as the concentration of D2EHPA and D,L‐MA. The results showed that both the distribution ratio and enantioselectivity were greatly improved by using a complex chiral selector rather than using the tartaric acid derivative by itself. Finally, it was found that the formation of mixed complex chiral selectors by mixing two tartaric acid derivatives with D2EHPA can improve the capacity of enantioselective extraction.