The copolymerization of carbon dioxide (CO2) and ethyl vinyl ether (EVE) at subcritical and super-critical 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 CO2 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), catalyst, a maximum yield of 3.2% polymer was obtained at 338 K, 6 MPa, and 45 h. The maximum value of the average CO2 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, fraction incorporated into the polymer as conditions changed from subcritical to super-critical. (C) 2003 Wiley Periodicals, Inc.