Synthesis of diethyl carbonate from urea and ethanol over lanthanum oxide as a heterogeneous basic catalyst
Synthesis of diethyl carbonate from urea and ethanol over lanthanum oxide as a heterogeneous basic catalyst
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DOI：
10.1016/j.fuproc.2014.05.029
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发表时间：
2014-10
影响因子：
7.5
通讯作者：
Shumin Xin;Wang Liguo;Huiquan Li;Kelin Huang;Li Fengjiao
中科院分区：
文献类型：
--
作者：
Shumin Xin;Wang Liguo;Huiquan Li;Kelin Huang;Li Fengjiao
以尿素和乙醇为原料，在不同金属氧化物催化剂上催化合成碳酸二乙酯。其中，沉淀法制备的氧化镧催化剂具有较高的催化活性。在乙醇/尿素摩尔比为10，反应温度为210 ° C，反应时间为3h的条件下，以La2O3 - 500为催化剂，DEC的产率可达38.6%。采用N2吸附、XRD、FT-IR和CO2-TPD等手段对催化剂的结构和表面性质进行了研究。根据这些结果，可以推断，高催化活性可能归因于氧化镧丰富的中等碱度。重要的是，如ICP-OES测试所证实的，没有明显的La浸出到所得混合物中。这一现象表明La_2O_3 - 500在反应过程中非常稳定，表现为非均相碱性催化剂。此外，对废催化剂进行简单的焙烧可以有效地恢复催化剂的活性。
The catalytic synthesis of diethyl carbonate from urea and ethanol was investigated over various metal oxide catalysts. Among them, the lanthanum oxide prepared by precipitation method exhibited much higher catalytic activity. In particular, 38.6% of DEC yield could be achieved at the reaction conditions of ethanol/urea molar ratio of 10, reaction temperature of 210 °C within 3 h over La2O3-500. The catalyst structures and surface properties were studied by N2adsorption, XRD, FT-IR and CO2-TPD. On the basis of these results, it can be inferred that the high catalytic activity could be attributed to the abundant medium basicity of lanthanum oxide. Importantly, as confirmed by ICP-OES test, there was no obvious leaching of La into the resulting mixture. This phenomenon indicated that La2O3-500 was very stable during the reaction and behaved as a heterogeneous basic catalyst. In addition, the facile calcination of the used catalyst could provide an efficient way to regenerate the catalytic activity.