【摘要】 研究了不同硼负载量的HZSM-5分子筛的物质结构,孔结构,表面酸性,以甲苯甲醇烷基化反应为探针反应考察了影响转化率和产物对位选择性的因素。结果表明:硼元素的引入,减小了分子筛的比表面积,孔容及孔径,增加了产物分子扩散阻力;减弱了外表面酸强度,抑制了优先扩散出分子筛孔道的对二甲苯二次异构化反应,从而获得了较高的对位选择性。反应对位选择性的提高可能是催化剂孔结构和外表面酸共同作用所致。更多还原

【Abstract】 The configuration,pore structure,surface acidity and catalytic performance of boron modified HZSM-5 with different Boron contents have been investigated.The reaction of toluene alkylation with methanol were used as a model reaction to evaluate toluene conversion and para-selectivity.The results showed that the boron impregnated reduces the surface area,pore volume and pore diameter of catalysts,lowers the acid strength,decreases diffusion rate of the production molecule,suppresses the second isomerization of paraxylene which diffuses first out of the pore of catalysts and then high Para-selectivity have been obtained through these modifications.The high para-selectivity obtained perhaps due to cooperated effect of pore structure and external surface acidity of catalysts.更多还原