Copolymerization of carbon dioxide and ethyl vinyl ether at subcritical and supercritical conditions

The copolymerization of carbon dioxide (CO 2 ) and ethyl vinyl ether (EVE) at subcritical and supercritical conditions was studied in the presence and absence of an aluminum triacetylacetonate [Al(acac) 3 ] catalyst. The experiments took place at 313–423 K and 4–15 MPa and for reaction times of 12–120 h. We confirmed that CO 2 could copolymerize with EVE with or without the Al(acac) 3 catalyst, regardless of whether the vessel wall material was Teflon or stainless steel. With the Al(acac) 3 catalyst, a maximum yield of 3.2% polymer was obtained at 338 K, 6 MPa, and 45 h. The maximum value of the average CO 2 fraction was about 50% (100% of the theoretical) at 338 K, 15 MPa, and 45 h. Results confirmed the mechanism and pathways proposed earlier by Soga et al. (1973). There was a trade‐off between yield and the CO 2 fraction incorporated into the polymer as conditions changed from subcritical to supercritical.