The CuBr2 /DMA (N, N-dimethylacetamide) homogeneous catalyst system was selected to be used for the reaction process of liquid-phase oxidative carbonylation of ethanol. The influences of the catalyst group distribution ratio on catalytic activity, the reaction time on oxidative carbonylation and the recycle performance of CuBr2/DMA catalyst system were investigated. The results show that the catalyst system exhibits good catalytic activity in oxidative carbonylation. When the concentration of CuBr2 in DMA solvent is 0.3 g⋅mL−1 and reaction time is 2.5 h, the ethanol conversion is as high as 36.2%. XRD characterization shows that the active center of copper catalyst is Cu (II), which is tranfered to Cu (I) at the beginning of reaction. In catalyst cycle expriment, the active center of copper catalyst is Cu (I), and the stability of CuBr in DMA solvent is comparable to CuBr2. The analyses of liquid products by using gas chromatography and gas chromatography–mass spctroscopy show that the products are diethyl carbonic, ethyl formate, ethyl acetate and ethyl propionate. On the basis of the above results, the formation of product and possible catalytic mechanism was explored.% 针对乙醇液相氧化羰基化合成反应工艺，筛选出 CuBr2/DMA(N, N-二甲基乙酰胺)均相催化体系，考察了催化剂组分配比对催化活性、时间对氧化羰基化反应的影响，以及 CuBr2/ DMA 催化剂体系的循环使用性能。结果表明，该催化剂体系表现出良好的氧化羰基化催化活性，当 CuBr2在 DMA 溶剂中浓度为0.3 g⋅mL−1，反应时间为2.5 h 时，乙醇的转化率达到36.2%，催化剂循环性能良好。XRD 表征显示，开始加入 CuBr2催化剂中 Cu(II)为催化主体，催化过程中 Cu(Ⅱ)被还原为 Cu(I)；循环试验中起催化活性的物质是 Cu(I)，且 CuBr 在溶剂 DMA 中表现出与 CuBr2相当的稳定特性。通过气相色谱及气-质联用对液相产物分析表明，产物分别是碳酸二乙酯、甲酸乙酯、乙酸乙酯和丙酸乙酯，并在此基础上探讨了产物形成和可能的催化机理。
展开▼
