Study of electronic effect in bifunctional catalysts for the copolymerization of CO2 and PO/CHO

Abstract

AbstractCarbon dioxide (CO2) is an easily available renewable carbon source that can be used as a comonomer in the catalytic ring‐opening polymerization of epoxides to form aliphatic polycarbonates. Herein, a series of new Salen‐Co(III) bifunctional catalysts were synthesized for the first time, and they were studied to catalyze the copolymerization of CO2 and propylene oxide (PO)/cyclohexene oxide (CHO). At the same time, the effects of reaction conditions (electronic effect, temperature, time) on catalytic activity and selectivity were investigated. The results show that the Salen‐Co(III) complexes with electron‐withdrawing groups have higher selectivity and activity for propylene carbonate (PPC)/cyclohexylene carbonate (PCHC). At the same time, the Salen‐Co(III) complexes can better catalyze the copolymerization of CHO and CO2 than that of PO and CO2. The catalytic efficiency of the four complexes increased with increasing temperature, and the best reaction condition is 80°C, 30 min and 2 MPa of CO2.