The combination of a CeO₂ catalyst and ethanol effectively promotes the direct synthesis of diethyl carbonate (DEC) from CO₂ and an orthoester. The reaction temperature, initial CO₂ pressure, and the ethanol/orthoester volume ratio were found to significantly influence DEC formation and were systematically studied to determine the optimum conditions. DEC amount of 5.2 mmol was obtained at 160 °C, 5 MPa of CO₂, and a reaction time of 20 h, providing high productivity (1.21 mmol_DEC mmol_catalyst⁻¹ h⁻¹) using a CeO₂ catalyst. The recovered CeO₂ catalyst was recyclable at least four times without any significant loss of activity when both triethyl orthoacetate and triethyl orthovalerate were used. A series of orthoesters bearing various alkyl substituents, aromatic substituents and halide moieties were evaluated for their activities with and without ethanol. In the presence of ethanol, orthoesters bearing longer alkyl substituents led to higher DEC yields, and orthoesters bearing aromatic and halide moieties negatively impacted DEC formation. In the absence of ethanol, triethyl orthoacetate provided the highest DEC yield; in all cases, the use of ethanol resulted in a greater DEC formation than when the reaction was performed without ethanol.

CeO ₂催化剂和乙醇的组合有效地促进了由CO ₂和原酸酯直接合成碳酸二乙酯(DEC) 。发现反应温度、初始 CO ₂压力和乙醇/原酸酯体积比显着影响 DEC 的形成，并进行了系统研究以确定最佳条件。在160°C、5 MPa的CO ₂和20小时的反应时间下获得5.2 mmol的DEC量，使用CeO ₂催化剂提供高生产率（1.21 mmol _DEC mmol_催化剂^-1 h ^-1）。回收的CeO ₂当同时使用原乙酸三乙酯和原戊酸三乙酯时，催化剂至少可回收四次而没有任何显着的活性损失。评估了一系列带有各种烷基取代基、芳族取代基和卤化物部分的原酸酯在有和没有乙醇的情况下的活性。在乙醇存在下，带有更长烷基取代基的原酸酯导致更高的 DEC 产率，带有芳香族和卤化物部分的原酸酯对 DEC 的形成产生负面影响。在没有乙醇的情况下，原乙酸三乙酯的 DEC 产率最高；在所有情况下，与不使用乙醇进行反应时相比，使用乙醇会导致更多的 DEC 形成。