REMARKABLY SELECTIVE FORMATION OF MACROCYCLIC AROMATIC CARBONATES - VERSATILE NEW INTERMEDIATES FOR THE SYNTHESIS OF AROMATIC POLYCARBONATES

A convenient and efficient route for preparation of macrocyclic aromatic carbonates, which provides a mixture of cyclic oligomers (from dimer to docosamer) which is almost totally devoid of linear oligomeric materials is described. Cyclic carbonate formation is achieved in a pseudo-high dilution, triethylamine-catalyzed hydrolysis/condensation reaction of bisphenol A bis(chloroformate) using CH2C12 and NaOH. The reaction is unusual in that long reaction times and dilute concentrations are not necessary. The role of the amine catalyst in discriminating between formation of cyclic vs linear oligomers is discussed. Cyclic oligomeric carbonates based on bisphenol A are solids, melting at 200-220 °C, anionic, ring-opening polymerization of which provides polymer with molecular weights significantly higher than possible with conventional techniques. The cyclization reaction is broad in scope, and many varied cyclic materials have been prepared. © 1990, American Chemical Society. All rights reserved.