镍硅基催化剂上偏三甲苯的加氢脱烷基反应

摘要

分别采用溶胶⁃凝胶法和浸渍法制备了一系列Ni／SiO2催化剂，将其用于催化偏三甲苯（1，2，4⁃TMB）的加氢脱烷基反应。结果表明，在制备过程中，无水柠檬酸（ CA）的加入量对催化剂的结构、表面性质、粒径及催化性能均有较大影响。催化剂表面L酸位上1，2，4⁃TMB几乎不发生歧化和异构化反应。镍硅体系催化剂上主要副反应为苯环加氢，通过调整还原镍的粒径可有效控制苯环加氢，从而提高了二甲苯（ BTX）的选择性。在最佳反应条件下，10Ni／Si⁃2�0催化剂上1，2，4⁃TMB的转化率最高为29�4％， BTX的选择性为99�9％。%A series of Ni/SiO2 catalysts, prepared via sol⁃gel and impregnation methods, respectively, was tested in the reaction of hydrodealkylation of 1,2,4⁃trimethylbenzene(1,2,4⁃TMB). The results showed that the volume of citric acid anhydrous( CA) have great influence on the structure, surface properties, particle size and catalytic properties. 1,2,4⁃TMB hardly reacted disproportionation and isomerization reaction on Lewis acid sites. The hydrogenation of benzene ring was main adverse reaction on Ni/SiO2 catalysts. The particle size of Ni on the catalyst could be adjusted in a certain range by changing the amount of CA, and the resultant catalysts exhibited high selectivity for Benzene⁃Toluene⁃Xylene( BTX) . With the optimum reaction conditions, the highest conversion of 1,2,4⁃Trimethylbenzene was 29�4% and the selectivity of BTX was 99�9% on the 10Ni/Si⁃2�0 catalyst.