Abstract: anhydride+ HzO in aqueous solutions of a number of vicinal diacids, chosen to correspond to relatively stable or very stable anhydrides. Such acids include di-, tri-, and tetraalkylsuccinic acids, certain alicyclic diacids, dialkylmaleic acids, and some alkyl substituted phthalic acids. In all cases, the driving force for formation of a stable anhydride appears to be relief of steric strain in the anhydride as compared to the corresponding ...