Cs2CO3-promoted polycondensation of CO2 with diols and dihalides for the synthesis of miscellaneous polycarbonates

Abstract

A one-pot protocol for the direct synthesis of polycarbonates through polycondensation of diols, dihalides and CO₂ in the presence of Cs₂CO₃ is described. The conditions were optimized by studying the polycondensation of CO₂ with 1,4-phenylenedimethanol and 1,4-dibromobutane as model monomers. Then, diols and dihalides with different spacers between the reactive groups including aliphatic, aromatic and poly(ethylene glycol) were tested under optimal conditions. Miscellaneous polycarbonates exhibiting molar masses in the range of 43 000 g mol⁻¹ (GPC) and conversion higher than 96% could be obtained. The proposed mechanism rules out the possibility of ether linkage formation during polycondensation and accounts for the creation of carbonate linkages in two different ways. The thermal properties of the synthesized polycarbonates were unveiled by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA).