Synthesis of polycarbonates and polycarbonate/polyester copolymers through an ester-carbonate exchange reaction

We describe the synthesis of polycarbonate by means of the polycondensation of diol formate and dialkyl carbonate through an ester-carbonate exchange reaction. The reaction of dodecane-1,12-diol formate (1a) and dipropyl carbonate (2e) in the presence of 5 mol%, compared to 1a, potassium tert-butoxide (tBuOK) in diglyme at 120 °C under reduced pressure (90–100 Torr) afforded high-molar-mass polycarbonate (PC). When polycondensation of 1a and diethyl carbonate (2d) was conducted in the presence of poly(1,12-dodecamethylene isophthalate) (PEs) in toluene at 60 °C under reduced pressure, both the synthesis of PC and the exchange reaction between the PC and PEs backbones proceeded simultaneously, and a statistical copolymer of PC and PEs was obtained. The composition of PC and PEs in the copolymer could be arbitrarily altered by changing the feed ratio of the monomers to PEs. The crystallization temperature (Tc) of the copolymer increased linearly with increasing PC content in the copolymer from −10.8 °C (100% PEs) to 47.3 °C (100% PC).