ZnO—Ga2O3／HZSM—5分子筛催化剂对C3—4烷烃芳构化反应的催化作用

用浸渍法将Ga、Zn以氧化物的形式负载于HZSM－5上，研究了其对C3－4烷烃芳构化的催化活性。结果表明，分别加入2％Ga和2％Zn后，当温度为520℃、空速为0．76h^-1时，具有较高的催化活性和芳烃选择性；反应进行100h后，催化活性无明显降低，显示出对C3－4烷烃芳构化良好的稳定性。用TPD和正丁胺Hammett酸性滴定法，测定了催化剂的表面酸性，发现加入Ga、Zn等组分后，催化剂的总酸量变化不大，而酸强度却有所增加；加入Zn组分后，催化剂的孔径变小，对二甲苯选择性增加。

Catalysis of ZnO-Ga_2O_3/HZSM-5 Zeolite in Aromatization of C_(3~4)-Hydrocarbons

The activity of HZSM-5 with loaded oxides of Ge and Zn prepared by impregnation has been studied. The experimental results show that the catalysts have high activity and selectivity for aromatization hydrocarbons of C3～4- hydrocarbons after the addition of 2% Ge and 2% Zn under the following conditions: the reaction temperature is 520 ℃ and space rate is 0.76 h-1. The activity of the catalyst does not decrease evidently after reaction for 100 h. Thus, the catalysts show high stabilization for aromatization. The acidity of the catalyst has been characterized by temperature programmed desorption of NH3(NH3-TPD) and Hammett acidity titration with butyric amine. The results show that the total acidity of the catalysts does not chang after the addition of Zn and Ga, but the acid strength increases a slightly. At the same time, it is found that the aperture of the catalyst decreases and the selectivity to p-xylene increases after the addtion of Zn.