The kinetics of one-pot synthesis of dimethyl carbonate (DMC) was investigated using ethylene epoxide (EO), methanol, and CO 2 as raw materials and a mixture of KI and K 2 CO 3 as a catalyst under supercritical CO 2 conditions. The reaction pathway of the one-pot process is that EO first reacts with CO 2 to form ethylene carbonate (EC) and then EC reacts with methanol to produce DMC and ethylene glycol (EG). EC formation is a relatively fast reaction, whereas the transesterification of EC with methanol to form DMC is a relatively slow reaction and the ratecontrol step of the one-pot synthesis. 2-Methoxyethanol (ME), which is the exclusive byproduct, is predominantly formed by the reaction of EC with methanol. An isothermal kinetics model and an isobaric kinetics model for the one-pot synthesis of DMC were developed. The relative standard deviations of the models from the experiment data were less than (15% and (10%, respectively. The effects of temperature and CO 2 density on the reaction rates and selectivity were discussed.

The synthesis of dimethyl carbonate (DMC) from ethylene oxide (EO), methanol, and carbon dioxide was investigated. In the proposed one-pot synthesis of DMC, the reaction of EO with CO2 was coupled simultaneously with the reaction of ethylene carbonate with methanol under reaction conditions at which carbon dioxide was in supercritical state. The catalysts were experimentally screened at temperatures from 80 to 140 °C and pressures from 5.0 to 15.0 MPa. The mixture of KI and K2CO3 showed the highest catalytic activity for the one-pot DMC synthesis. The preferential weight ratio of KI to K2CO3 in the mixed catalyst ranges from 1:3 to 5:3. The effects of the reaction conditions, such as catalyst concentration, temperature, pressure, reaction time, and reactant compositions, were experimentally studied. High temperature favors the formation of the desired products, DMC and ethylene carbonate. The effect of pressure on the DMC yield is not significant. A high EO content in the feed is beneficial to increasing the selectivity of the desired products. Using the mixture of KI and K2CO3 (weight ratio of KI/K2CO3 = 1:1) as the catalyst with a molar ratio of catalyst to EO of 0.05, the DMC selectivity can reach above 73.0% at 100.0% EO conversion with less than 4.0% selectivity of the byproduct 2-methoxyethanol at the appropriate reaction conditions.