STUDIES ON THE MECHANISM OF AMINE-CATALYZED CYCLIC OLIGOMERIC CARBONATE FORMATION

A mechanism for the selective formation of cyclic oligomeric carbonates via triethylamine-catalyzed, pseudo-high dilution hydrolysis/-condensation of bisphenol A-bischloroformate is proposed. The mechanism is based on results of model and cyclization reactions using amines of various structure. Intermediacy of an acyl ammonium salt is invoked for both hydrolysis and condensation reactions. An oligomeric carbonate with a phenoxide on one end and an acyl ammonium salt on the other end is proposed as the immediate precursor to a cyclic oligomer.