P. Ballone and R. O. Jones

Last year we reported the results of density functional calculations on the reactions of lithium and sodium phenoxide molecules with the cyclic tetramer of bisphenol-A polycarbonate (BPA-PC). Both molecules catalyze ring-opening with small energy barriers (DE = 4.0,2.5 kcal/mol, respectively), and the reactants and products -a chain with a phenyl carbonate at one end and a phenoxide at the other -have almost the same total energies. The alkali atom at the end of the chain can repeat this process, producing long chains: a "living polymer". If the reaction, used in the industrial production of PC, is not exothermic, why does polymerization occur? We discuss here the role played by entropy using a classical simulation based on the mechanism suggested by the DF calculations.