Terpolymerization of Carbon Dioxide with Propylene Oxide and -Butyrolactone Catalyzed by SalenCoIII(2,4-dinitrophenoxy) and Lewis-Basic Cocatalyst

The terpolymerization of -butyrolactone (GBL), propylene oxide (PO), and CO2 catalyzed by SalenCo(III)(2,4-dinitrophenoxy) (Salen = N,N-bis(3,5-di-tert-butylsalicylidene)-ethylenediimine) (1) was studied in the presence of (Bu4NBr)-Bu-n. The reaction conditions, such as (Bu4NBr)-Bu-n/the 1 molar ratio, CO2 pressure, reaction temperature, reaction time, and GBL/PO molar ratios were optimized. A reasonably high viscosity-average molar mass of 115.9 kg/mol and yield of 118.6 g/g of catalyst were achieved at an appropriate combination under the optimum conditions. The structure of as-prepared product was characterized by the IR and H-1 NMR spectra. Compared with a copolymer of PO/CO2, the thermal property of terpolymer has been evaluated largely. The reactivity ratios of CO2 and GBL (r(CO2) = 5.62 and r(GBL) = 0.31) were experimentally evaluated by the Fineman-Ross methodology.