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在520—750℃范围,用SiCl_4蒸汽处理HZSM-5沸石,其晶体结构不受破坏,而硅铝比大大提高。低于620℃时,脱铝随温度升高而增加;高于620℃,脱铝减少。经540℃和560℃分别处理8小时,所得的样品硅铝比为110和126,B酸中心数大为减少,B酸强度较为适中(由乙烯吸附热所表征的B酸强度为24.8—24.1kJ/mol)。用作甲苯加甲醇甲基化反应的催化剂,甲苯转化率为25—29％,对甲苯的选择性大于85.0％。
In the range of 520-750 ℃, the HZSM-5 zeolite treated with SiCl 4 steam does not destroy the crystal structure, but the Si / Al ratio is greatly increased. Below 620 ℃, dealuminization increases with increasing temperature; above 620 ℃, dealuminization decreases. After treated at 540 ℃ and 560 ℃ for 8 hours respectively, the Si / Al ratio of samples obtained was 110 and 126, the number of B acid centers was greatly reduced, and the B acid intensity was moderate (the B acid strength was 24.8-24.1 kJ / mol). For the toluene / methanol methylation reaction, the conversion of toluene is 25-29% and the selectivity to toluene is more than 85.0%.