Solvent extraction of penicillin

Abstract

Abstract The extraction method for the purification and concentration of penicillin is reviewed. The theoretical basis underlying the extraction process is examined. A simple distribution formula reproduces the results well and in used to examine the dependence of the selectivity of a solvent on pH of extraction. A number of solvents were tested, most of them show better solvent power for penicillin than the widely‐used amyl acetate. Outstanding amongst these solvents are the cyclic ketones such as methylcyclo‐hexanone and dimethylcyclohexanone.* With these solvents efficient extraction at pH4 is possible, thus avoiding contact of penicillin with solutions of greater acidity where it becomes unstable. The selectivity of these solvents is examined and found to increase with the pH of extraction. At pH4 the selectivity of methylcyclobexanone approached that of chloroform, the latter being a very selective solvent for penicillin.