CuBr_3L_2络合催化剂羰基合成碳酸二甲酯的反应研究  

Synthesis of Dimethyl Carbonate by Oxidative Carbonylation with CuBr_3L_2 Catalyst

作　　者：杨洋[1] 刘晓勤[1] 刘定华[1] 姚虎卿[1] 

机构地区：[1]南京工业大学化学化工学院,江苏南京210009

出　　处：《高校化学工程学报》2007年第4期633-639,共7页Journal of Chemical Engineering of Chinese Universities

摘　　要：开发了甲醇液相羰基化法合成碳酸二甲酯的新型CuBr3L2络合催化剂。实验结果表明,该催化剂在反应温度373-83K、压力3.0-3.5MPa、催化剂质量浓度0.15-0.20g·mL^-1、反应时间4-6h的条件下,甲醇的转化率可达23%-25%,碳酸二甲酯选择性为96%-98%。且该催化剂性能稳定,可反复使用。XPS等表征发现配位剂四丁基溴化铵（简称L）的添加有助于表面活性物种Cu（I）的形成,推导了可能的反应机理。对该催化体系进行动力学研究,推导出合适的动力学方程以及相关的动力学参数。该反应是一近似二级反应,反应表观速率常数Kp与催化剂质量浓度和反应温度有关,且Kp与催化剂质量浓度的平方成正比;高温高压不利于主反应的进行,导致目的产物选择性的下降。A novel type of CuBr3L2 complex catalyst for dimethyl carbonate （DMC） synthesis by oxidative carbonylation of methanol in liquid-phase was reported. The results show that under the reaction conditions of temperature 373-383 K, pressure 3.5 MPa, reaction time 4-6 h and the mass concentration of the proposed catalyst in methanol 0.15-0.20 g·mL^-1, the conversion rate of methanol can be maintained around 23%-25% and the selectivity of DMC is about 96%-98%. The catalyst proposed has a stable catalytic activity and can be used repeatedly at least 5 recycles. The complex catalysts prepared were characterized by XPS and EPR, and the results indicate that the introduction of complexing agent tetrabuthylammonium bromide （L） can promote the substantial formation of Cu（ I ） species for DMC synthesis. The synthesis reaction mechanism was studied, and the reaction kinetics with CuBr3L2 complex catalyst for DCM synthesis was investigated. The reaction kinetic equation and parameters of the equation were obtained. The results show that the reaction of methanol oxidative carbonylation to DMC by the complex catalyst proposed is an approximate second order reaction, and the reaction rate constant, Kp, is related to reaction temperature and is directly proportional to the square of the mass concentration of catalyst, The experiments also show that high reaction temperature and pressure are unfavorable to the main reaction and will cause the decrease of DMC selectivity.

关 键 词：碳酸二甲酯 甲醇 氧化羰化 液相 动力学 

分 类 号：TQ032.42[化学工程] TQ426.92