助剂对合成碳酸二甲酯用活性炭负载Wacker催化剂结构和性能的影响

Effect of Promoters on Structure and Performance of Activated Carbon-Supported Wacker-Type Catalysts for Synthesis of Dimethyl Carbonate

以碱金属或碱土金属的盐或氢氧化物为助剂修饰活性炭 (AC)负载的Wacker催化剂PdCl2 CuCl2 .甲醇气相氧化羰基化合成碳酸二甲酯 (DMC)的反应活性评价结果表明 ,以乙酸钾 (KOAc)为助剂的效果最好 .在KOAc/CuCl2 摩尔比为 1 0的条件下制备的催化剂用于该合成反应时 ,DMC的时空产率提高了 5倍 .XRD ,SEM及EPR表征结果显示 ,在催化剂中加入适量的KOAc ,有利于Cu2 Cl(OH) 3 物相在载体表面的形成和分散 ,从而加快了催化剂活性物种Cu和Pd的氧化还原循环速度 .

Activated carbon-supported Wacker-type catalysts (PdCl 2-CuCl 2) were prepared by using salts and hydrates of alkali and alkaline earth metals as promoters. It is revealed that the catalyst modified by KOAc exhibited the best catalytic performance in dimethyl carbonate (DMC) synthesis by oxidative carbonylation of methanol. The space-time yield (STY) of DMC over the catalyst with KOAc/CuCl 2=1 0 was six times the STY over the unmodified catalyst. The results of XRD, SEM and EPR suggested that a proper amount of KOAc was in favor of the formation and dispersion of Cu 2Cl(OH) 3 species, and therefore the redox cycle of active Cu and Pd species was expedited.