A novel one-pot process for the preparation of linear and hyperbranched polycarbonates of various diols and triols using dimethyl carbonate. Issue 21 (21st February 2017)

• Record Type: Journal Article
• Authors: Sun, Jingjiang; Aly, Kamal Ibrahim; Kuckling, Dirk
• Is Part Of: RSC advances. Volume 7:Issue 21(2017)
• Page Start: 12550
• Page End: 12560
• Publication Date: 2017-02-21
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7ra01317e
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A novel one-pot method for preparation of high molecular-weight linear and hyperbranched polycarbonates from diols and triols with dimethyl carbonate. Abstract : 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 °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 Å 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 M n up to 16 000 g mol −1 and low molar mass distributions ( Đ M < 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.