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分别采用溶胶-凝胶法和浸渍法制备了一系列Ni/SiO_2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 / SiO 2 catalysts were prepared by sol-gel method and impregnation method respectively, which were used to catalyze the hydrodealkylation of p-trimethylbenzene (1,2,4-TMB) .The results showed that during the preparation process , The addition amount of anhydrous citric acid (CA) has a great influence on the structure, surface properties, particle size and catalytic performance of the catalysts.The disproportionation of 1,2,4-TMB on the surface of L The main side reaction on Ni-Si catalyst is hydrogenation of benzene ring, and the hydrogenation of benzene ring can be effectively controlled by adjusting the particle size of nickel reduction, thereby increasing the selectivity of xylene (BTX) .In the optimum reaction conditions , The conversion of 1,2,4-TMB on the 10Ni / Si-2.0 catalyst was up to 29.4% and the selectivity of BTX was 99.9%.