Highly efficient synthesis of diethyl carbonate via one-pot reaction from carbon dioxide, epoxides and ethanol over KI-based binary catalyst system
Highly efficient synthesis of diethyl carbonate via one-pot reaction from carbon dioxide, epoxides and ethanol over KI-based binary catalyst system
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DOI：
10.1016/j.apcata.2013.11.031
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发表时间：
2014-02
影响因子：
5.5
通讯作者：
Wang Liguo;Huiquan Li;Shumin Xin;P. He;Yan Cao;Li Fengjiao;X. Hou
中科院分区：
文献类型：
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作者：
Wang Liguo;Huiquan Li;Shumin Xin;P. He;Yan Cao;Li Fengjiao;X. Hou
首次报道了以二氧化碳、环氧乙烷和乙醇为原料，通过一锅法直接合成碳酸二乙酯。系统研究了催化剂种类和反应条件对DEC合成性能的影响。结果表明，采用易得的KI和乙醇钠组成的均相二元催化剂体系，在较温和的反应条件下（443 K，3 MPa CO2初压，2 h），一锅法合成DEC的产率可达63.6%.在优化的工艺条件下，环氧乙烷与乙醇醇解开环生成少量（< 5%）的2-乙氧基乙醇。此外，热力学评估表明，一锅反应的标准摩尔焓是放热的（Δ r H m θ=− 19. 7 0 kcal/mol< 0）。与CO2和乙醇直接合成DEC相比，EO的参与促进DEC的形成，同时产生乙二醇。这种策略也可以成功地扩展到终端环氧化物底物。并根据实验结果提出了可能的反应机理。该方法为直接利用CO2生产碳酸二乙酯提供了一条高效的途径，在工业化生产碳酸二乙酯方面具有良好的应用前景。
The synthesis of diethyl carbonate (DEC) directly from carbon dioxide, ethylene oxide (EO), and ethanol via one-pot reaction is reported for the first time. The effects of catalyst species and reaction variables on the synthetic performance of DEC were systematically studied. The integration of easily available KI and sodium ethoxide as homogeneous binary catalyst system was found to be very active for the one-pot reaction, and 63.6% of the DEC yield could be achieved under relatively mild reaction conditions (443 K, 3 MPa CO 2 initial pressure, 2 h). The byproduct of 2-ethoxyethanol, which is predominantly formed via alcoholysis of EO by ethanol through ring-opening reaction, was produced with small amount (< 5%) under optimized conditions. Additionally, the thermodynamic evaluation reveals that the standard molar enthalpy of one-pot reaction is exothermic (Δ r H m θ=− 19. 7 0 kcal/mol< 0). In comparison with the direct synthesis of DEC from CO 2 and ethanol, the involvement of EO facilitates the formation of DEC, simultaneously with glycol produced. This strategy could also be successfully expanded to terminal epoxide substrates. Furthermore, a possible mechanism of the reaction was proposed on the basis of experimental results. This method provides a highly effective way to produce DEC via directly chemical utilization of CO 2 and shows promising application in the manufacture of diethyl carbonate on an industrial scale.