Coupling reaction of CO2 and propylene oxide catalyzed by DMC with co-complexing agents incorporated via ball milling

Abstract

Mechanical grinding as a clean, efficient and environmentally friendly synthetic method has shown great potential in the chemical synthesis. It now emerges as an effective route for the synthesis of double metal cyanide (DMC) catalyst. In this work Zn–Fe DMCs were successfully obtained by employing ball milling. The co-complexing agents (co-CAs) were incorporated into the structure of DMC simultaneously during the grinding process. The FT-IR spectra and elemental analysis indicated the incorporation of various co-CAs within DMCs. It was found that the resulting DMC catalysts are amorphous with a monoclinic phase and had moderate catalytic activity. The DMC catalysts were proven to be effective for both cycloaddition and copolymerization between CO2 and propylene oxide under controlled reaction conditions. The DMCs exhibited high conversion and yields from 93.6 to 97.3% with high selectivity for the cyclic carbonate. For copolymerization, the DMCs showed relatively modest activity but yielded poly(propylene carbonate) with high molecular weight (Mn 61K) and narrow polydispersity index (PDI 1.46).