Ring-opening polymerization of epoxides and ring-opening copolymerization of CO2 with epoxides by a zinc amino-bis(phenolate) catalyst

摘要

A one-pot synthesis of poly(ether-co-carbonates) catalyzed by an amino-bis(phenolate) zinc catalyst [L] Zn2Et2(THF) 1 (where [H2L] = n-propylamino-N,N-bis(2-methylene-4,6-di-tert-butylphenol) has been developed. Ring-opening polymerization (ROP) of cyclohexene oxide (CHO) can be performed by 1 with and without addition of BnOH or PPNCl as co-catalysts. The ROP of CHO can be inhibited by CO2 pressurization, which leads to the formation of polycarbonate blocks, or presence of other epoxides, which leads to the formation of poly (ether-co-carbonate) containing carbonate linkages and ether linkages. Polycarbonate formation was observed at 1 bar CO2 giving 23% carbonate linkages at this pressure. At 20 bar CO2, 92% carbonate formation was achieved in the presence of limonene oxide (LO). Poly(ether-co-carbonates) from mixtures of epoxides could be synthesized by changes in reaction temperatures and pressures.