CuBr/DMAP/DMA催化乙醇氧化羰基化合成碳酸二乙酯反应的研究

CuBr/DMAP/DMA Catalyzed Oxidative Carbonylation for Diethyl Carbonate Synthesis

为了提高乙醇氧化羰基化合成碳酸二乙酯(DEC)催化反应性能,考察了不同配体、催化剂配比、催化剂浓度、反应温度、反应时间等条件对乙醇转化率和DEC选择性的影响,并利用气相色谱-质谱联用(GC-MS)和气相色谱(GC)对反应产物进行了定性和定量分析。结果表明,当以4-二甲氨基吡啶(DMAP)为配体,CuBr:DMAP=1:2,在合适的反应条件下(催化剂浓度0.25 mol·L-1,反应压力3.5 MPa,反应温度100℃,40 mL N,N-二甲基乙酰胺(DMA)),乙醇转化率为28.6%,DEC选择性为99.9%。通过探讨反应机理,认为CuBr/DMAP/DMA催化体系不仅有利于主反应控制步骤CO的插入反应,有助于中间体的形成,缩短了反应的诱导期,反应时间由180 min减至90 min,也抑制了副产物乙酸乙酯中间体的形成,提高了反应的选择性。

In order to improve the diethyl carbonate （DEC） synthesis using oxidative carbonylation of ethanol, the effects of ligands, catalyst composition and concentration, reaction temperature and time on the ethanol conversion rate and DEC selectivity were investigated. Gas chromatography-mass spectroscopy （GC-MS） and gas chromatography （GC） were used to identify and quantify the reaction products. The results show that when 4-dimethylaminopyridine （DMAP） is used as the ligand with the CuBr/DMAP molar ratio of 1/2, the ethanol conversion rate can reach 28.6%and the selectivity of DEC is 99.9%under suitable reaction conditions （catalyst concentration：0.25 mol？L-1, pressure：3.5 MPa, temperature：100℃, 40 mL N,N-dimethylacetamide ）. Reaction mechanism study shows that the CuBr/DMAP/DMA catalytic system prefers the insertion of CO （the rate-controlling step） and the formation of intermediate, which reduces the induction period. The reaction time decreases from 180 min to 90 min and the formation of the byproduct ethyl acetate intermediate is suppressed. The reaction selectivity is also enhanced.