【摘要】 对苯胺缩合生成二苯胺用H-beta分子筛催化剂进行研究,考察分子筛硅铝比和NH₄F改性对H-beta分子筛催化苯胺缩合反应的影响,采用NH₃-TPD和Py-IR对催化剂进行表征。结果表明,B酸是催化苯胺缩合的活性中心,低硅铝比与适当卤素处理均可提高B酸含量,有利于缩合反应。反应温度320℃,空速0. 2 h^-1,0. 125 mol·L^-1的NH₄F溶液处理硅铝比为25的H-beta分子筛上,二苯胺的收率达到34. 68%。基于催化活性位点的研究,探讨了苯胺缩合反应机理。更多还原

【Abstract】 H-beta zeolite catalyst for the condensation of aniline to diphenylamine was studied. The effect of SiO₂/Al₂O₃ ratio and NH₄F modification on the condensation of aniline were investigated. The catalyst was characterized by NH₃-TPD and Py-IR. It was found that Brnsted acid was the active center for aniline condensation,and the low ratio of SiO₂/Al₂O₃ and the appropriate treatment by halogen could increase the content of Brnsted acid. The yield of diphenylamine was 34. 68% at the temperature of 320 ℃ and the space velocity of 0. 2 h^-1 over H-beta zeolite with SiO₂/Al₂O₃ ratio of 25 and modified by NH₄F of 0. 125 mol·L^-1. The mechanism of aniline condensation was discussed based on study of catalytic active sites.更多还原