A novel one-pot process for the preparation of linear and hyperbranched polycarbonates of various diols and triols using dimethyl carbonate

作者：Sun Jingjiang; Aly Kamal Ibrahim; Kuckling Dirk^*

来源：RSC Advances, 2017, 7(21): 12550-12560.

DOI：10.1039/c7ra01317e

A new eco-friendly strategy for the preparation of linear and hyperbranched polycarbonates was developed. Our work referred to a one-pot condensation polymerization of various alcohols (diols and triols) with equivalent amounts of eco-friendly dimethyl carbonate (DMC) at 120 degrees C, atmospheric pressure and in 1,4-dioxane solution using 4-dimethylaminopyridine (DMAP) or lithium acetylacetonate (LiAcac) as a catalyst. Polymer chains were built by pure transesterification of hydroxyl and methyl carbonate chain ends, and the single byproduct (methanol) was removed using a pressure-equalized addition funnel filled with 4 angstrom molecular sieves as the crucial equipment in this work. Using this strategy, hyperbranched polycarbonates with high molar masses (M-n up to 10 000 g mol(-1) and M-w up to 64 000 g mol(-1)) and high hydroxyl end group contents (up to 94%) were successfully prepared using dimethyl carbonate instead of toxic phosgene or phosgene-based monomers for the first time. In addition, linear aliphatic polycarbonates of various diols were also synthesized with Mn up to 16 000 g mol(-1) and low molar mass distributions (DM < 1.70). Another eco-friendly aspect of this work was the use of equimolar amounts of DMC to avoid waste and the disposal of excess DMC; in a classic 2-step polycondensation for polycarbonate synthesis excess DMC is a prerequisite in order to obtain high molar masses.

• 出版日期2017