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用脉冲微反方法研究了不同温度下不同硅铝比的HZSM-11分子筛上邻二甲苯异构化活性和选择性。结果表明,硅铝比增加,二甲苯异构化活性变化不大。用TPD技术研究了不同硅铝比的HZSM-11的酸性质,测得了NH_2在HZSM-11上的程脱谱。结果表明,在HZSM-11表面上有两种强度的酸中心。硅铝比增加,弱酸中心数减少,强酸中心数基本不变。
The isomerization activity and selectivity of o-xylene on HZSM-11 zeolites with different Si / Al ratios at different temperatures were investigated by means of pulsed micro-inversion. The results show that the silicon-aluminum ratio increases, xylene isomerization activity changes little. The acidity of HZSM-11 with different Si / Al ratios was studied by TPD technique, and the desorption spectrum of NH2 on HZSM-11 was measured. The results show that there are two kinds of acid sites on the surface of HZSM-11. Silicon-aluminum ratio increased, the number of weak acid centers decreased, the number of strong acid centers remained essentially unchanged.