COPOLYMERIZATION OF CO_2 WITH STYRENE OXIDE USING DOUBLE METAL CYANIDE CATALYST BEARING ETHYL LACTATE AS ECO-FRIENDLY COMPLEXING AGENT

摘要

Double metal cyanide catalysts are known to be extremely useful and active catalysts for the ring-opening polymerization of epoxides as well as copolymerization of CO_2 and epoxides. DMC was utilized for the copolymerization of CO_2 to styrene oxide (SO) by the introduction of ethyl lactate as complexing agent. Environmentally friendly and nontoxic lactate esters are effective CAs of DMC catalysts for the copolymerization between SO and CO_2. A series of DMC catalysts at different [Zn]/[Co] ratios, precipitation temperature and various lactate esters as complexing agents without co-complexing agents were synthesized and characterized through FT-IR, XPS, EA, TGA and XRD. Ethyl lactate as a complexng agent is the most active for copolymerization among lactate esters due to suitable polarity and steric effect. Polycarbonates with CO_2 incorporation of 83 %, a structure of nearly alternating SO and CO_2 and a molecular weight (M_n) of 14.3 kg/mol were prepared at moderate reaction conditions like 4 h, 50 ℃, cat. 3 mg.