Effect of dicarbonyl complexing agents on double metal cyanide catalysts toward copolymerization of CO2 and propylene oxide

Abstract

Functional polycarbonate polyols have been synthesized by CO2/propylene oxide (PO) copolymerizations using various Zn(II)-Co(III) double metal cyanide (DMC) catalysts bearing α-, β-, γ-, and δ-dicarbonyl complexing agents (CAs) including dicarboxylic acids, diesters, ketoester, and diketones. The resultant heterogeneous catalysts are intensively characterized by infrared, absorption and X-ray photoelectron spectroscopies, X-ray powder diffraction, and elemental analysis. The produced polycarbonate polyols are characterized using infrared and nuclear magnetic resonance spectroscopies, gel permeation chromatography, differential scanning calorimetry and thermogravimetric analysis measurements. The catalysts bearing β-, γ-, and δ-dicarbonyl CAs exhibit high activity towards CO2/PO copolymerization and produce polycarbonate polyols with high carbonate content, wide range of molecular weight and narrow polydispersity. The functionality of the resultant polycarbonate polyols varies depending on the type of CAs and the functionality of initiators.