Polymers of carbonic acid .12. Spontaneous and hematin-initiated polymerizations of trimethylene carbonate and neopentylene carbonate

The purity and reactivity of trimethylene carbonate (TMC, 1,3-dioxan-2-one) depends largely on the purification procedure. Vacuum distillation and recrystallization from CCl4 are less efficient than recrystallization from tetrahydrofuran (THF) or ethyl acetate (EtAc). TMC recrystallized from CCl4 contains between 5 and 8 mol-% of CCl4 which inhibits the spontaneous polymerization at temperatures greater than or equal to 100 degrees C as do other alkylating agents. The spontaneous polymerization of pure TMC may give high yields (up to 90%) and high molecular weights (weight-average molecular weights up to 200 000). The polymerization mechanism is discussed. It seems to be anionic in nature. Neopentylene carbonate (NPC, 5,5-dimethyl-1,3-dioxan-2-one) is rather insensitive to the purification procedure and does not undergo spontaneous polymerization at temperatures less than or equal to 125 degrees C. Hematin initiates the polymerizations of TMC and NPC in bulk, but high yields and high molecular weights were only obtained in the case of TMC.