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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.

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Using high-frequency tide gauge observations from 1980 to 2017, we analyzed changes in extreme sea levels (ESLs) along the Chinese coast to examine whether extreme sea-level rise acceleration could be observed. The results indicated that the ESL has risen with fluctuations along the Chinese coast. The ESL also featured significant decadal variabilities. The ESL rise was accelerated at most tide gauges throughout the whole study period, especially after the 1980s, while the acceleration patterns varied with station location. The mean sea level (MSL) change was confirmed as the major driver of the ESL change according to the analysis. However, the skew surge may also have affected the extremes at many of the tide gauges, which was observed after detrending. The extreme/MSL had a significant positive correlation with the Atlantic Multidecadal Oscillation, which is supposed to affect the MSL through a combination of variation in sea surface temperature, pressure system, and wind. That sea level oscillation is dominated by Atlantic Multidecadal Oscillation should be taken into consideration when studying accelerations in the rate of ESLs and of MSLs along the Chinese coast.Other studies revealed that the long-term trend of MSL is nonlinear and that the MSL rise has accelerated in recent years

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