The formation of diacetyl and acetoin from α‐acetolactic acid

Abstract

Abstract Of several ions tested, only Fe +3 , Cu +2 and Al +3 catalysed the decarboxylation of α‐acetolactic acid at pH 4.8. At pH 2.2, only Fe +3 and Cu +2 were active. Fe +3 and Cu +2 were shown to form complexes with α‐acetolactic acid. Fe +3 and Cu +2 not only decarboxylated but also oxidized α‐acetolactic acid, with, as a result, formation of diacetyl. Decarboxylation of α‐acetolactic acid by these ions is compatible with the mechanism suggested by Martell and Calvin . α‐Acetolactic acid is subject to autoxidation. 2‐Butene‐2,3‐diol may be an intermediate product.