Zn-Cr double metal cyanide catalysts synthesized by ball milling for the copolymerization of CO2/propylene oxide, phthalic anhydride/propylene oxide, and CO2/propylene oxide/phthalic anhydride

A highly active double metal cyanide complex (DMC) catalyst based on Zn-Cr was successfully synthesized by ball milling, an environmentally-friendly and efficient synthetic technique. The Zn-Cr DMC showed not only high catalytic activity for the alternating copolymerization of CO2 with propylene oxide (4 MPa, 70 degrees C, 24 h) and phthalic anhydride with propylene oxide (110 degrees C, 5 h), but also effectiveness for the terpolymerization of CO2, propylene oxide and phthalic anhydride (4 MPa, 70 degrees C, 24 h) under controlled conditions. The Zn-Cr DMC showed relatively modest activity and yielded polymers with high molecular weight (Mn PPC: 68.6 K, PPA: 4.1 K, PPCPA: 15.9 K) and narrow polydispersity index (PDI PPC: 1.68, PPA: 1.29, PPCPA: 1.09). FT-IR, H-1 NMR and C-13 NMR confirmed product formation. (C) 2015 Elsevier B.V. All rights reserved.