Extraction of 7-aminocephalosporanic acid with secondary, tertiary, and quaternary amines

Extraction of 7-aminocephalosporanic acid (7-ACA) has been investigated using secondary and tertiary amines and a quaternary ammonium salt (Aliquat-336) as the carriers. The values of the distribution coefficients have been reported in a range of aqueous-phase pH values and concentrations of 7-ACA using different carriers in n-butyl acetate as the diluent. As expected, ion-pair extraction with secondary and tertiary amines exhibits lowerings of the distribution coefficient with increase of pH, whereas the ion exchange extraction with quaternary ammonium chloride (Aliquat-366) exhibits an opposite but more pronounced pH dependence, providing at the same time higher values of distribution coefficient at high values of pH. Both the extraction principles can be exploited to achieve extraction and reextraction of 7-ACA in the pH range of 5 to 8 in which it is relatively stable.