MgO/ZSM-5催化乙苯与碳酸二乙酯合成对二乙苯

以负载型MgO/ZSM-5为催化剂,研究了乙苯与碳酸二乙酯烷基化合成对二乙苯的过程。通过等体积浸渍法制备了一系列MgO/ZSM-5催化剂,并用XRD、NH3-TPD和吡啶红外光谱等手段对催化剂的结构和酸性进行了表征。在气相连续流动固定床反应器内考察了MgO负载量、反应的工艺条件（反应温度、质量空速、乙苯与碳酸二乙酯物质的量比）对乙苯与碳酸二乙酯烷基化反应合成对二乙苯的影响。结果表明：MgO改性对ZSM-5分子筛的结构影响不大,但催化剂上的酸性质明显改变。随着MgO负载量的增加,乙苯转化率降低,而对二乙苯选择性明显提高,这主要是由于催化剂上的酸性质变化引起的。

Study of the Synthesis of para--Diethylbenzene by Alkylation of Ethylbenzene with Diethyl Carbonate over MgO/ZSM--5

p--Diethylbenzene （p--DEB） was synthesized by alkylation of ethylbenzene （EB） with diethyl carbonate （DEC） over MgO/ZSM--5. A series of MgO/ZSM--5 catalysts were prepared by impregnation method and the structure and acidity of the catalysts were characterized by means of X--ray diffraction, N H3--TPD, and pyridine--IR techniques. The effects of MgO loadings and reaction conditions （reaction temperature,＂ WHSV and the ratio of EB to DEC） on the synthesis of p--DEB by alkylation of EB with DEC were investigated. The results of the characterization indicated that the structure of ZSM-- 5 was hardly affected after MgO modification, however, the acidity of the catalysts changed obviously. Catalytic evaluation demonstrated that with the increase in the loadings of MgO the conversion of EB decreased, while the selectivity to p--DEB increased dramatically, which can also be ascribed to the changes in the a- cidity after MgO modification.