负载CuCl_2催化剂上甲醇气相氧化羰化制碳酸二甲酯的研究

Supported CuCl_2 Catalysts for Vapor Phase Oxidative Carbonylation of Methanol to Dimethyl Carbonate

经胺基官能团化介孔分子筛负载型CuCl2催化剂,表现出较高的甲醇转化率和碳酸二甲酯(DMC)收率以及较好的催化剂寿命.采用XRD、XPS和BET等对催化剂的体相结构和表面物种进行研究表明:(1)所合成介孔分子筛具有2～4nm的规整孔通道,足以容纳胺基官能团和CuCl2物种,同时留下供反应分子扩散和反应的适度空间,产生足够高的反应活性;(2)CuCl2与胺基之间存在的配位作用,有利于稳定活性中心铜离子,并使在甲醇气相氧化羰化制碳酸二甲酯反应条件下Cu(II)/Cu(I)之间的"氧化 还原"过程易于进行.

Pure silica mesoporous molecular sieves MCM-41 and MCM-48 organofunctionalized with 3-aminopropyltrimethoxysilane and N-[(3-trimethoxysilyl) propyl]ethylenediamine, respectively, were served as supports to immobilize CuCl_2 with conventional impregnation method. The supported Cu catalysts showed a considerable enhancement in the reaction rate in heterogeneous vapor-phase oxidative carbonylation of methanol to produce dimethyl carbonate in comparison with that obtained by CuCl_2 supported on non-functionalized mesoporous silicas under identical conditions. The electronic donation of the amino-groups, the accessibility and dischargeability of reactants in the regular mesopores probably account for the good catalytic performance as evidenced by the characteristic studies with XRD, BET, TG-DTA and XPS.