| 摘要 |
The invention relates to a process for the preparation of polycarbonates. In particular the invention relates to a process for the preparation of polycarbonates or copolymers thereof, by ring-opening polymerization of five-mem bered cyclic carbonates, said process comprises the step of homo- or copolymerizing in the presence of at least one catalyst, one or more compounds of formula (I), stereoisomers, racemics, or mixtures thereof; optionally with one or more cyclic esters, stereoisomers, racemics, or mixtures thereof; wherein each dotted bond "a" and "b" are a solid bond, a wedged bond, or a hashed wedged bond; and R21 and R22 taken together with the carbon atoms 4 and 5 of the cyclic carbonate form a ring selected from C5-9cycloalkylene, C5-9cycloalkenylene, and C6-12arylene, said ring being optionally substituted with one or more substituents each independently selected from halo, hydroxyl, C1-6alkyl, haloC1-6alkyl, C1-6alkoxy, haloC1-6alkoxy, C6-12aryl, C1-6alkylthio, carboxyl, C1-6 alkoxycarbonyl, C1-6alkylcarbonyloxy, amino; or mono- or di-C1-6alkylamino. |
