硅改性ZSM-5催化剂上甲苯歧化反应性能的研究

采用液相沉积法研究了硅改性剂对择形分子筛的表面酸性和孔结构参数的影响。利用甲苯歧化反应作为探针反应,考察了改性剂的种类和改性次数等对催化剂的选择性能和活性的影响。结果表明,硅改性剂显著改变分子筛的强酸性,可以对择形分子筛的孔结构进行精细调节。分子筛改性后甲苯的转化率有所降低,但是对二甲苯的选择性明显提高。

Research of toluene disproportionation reaction on silica-modified ZSM-5 zeolite catalysts

The influences of silica-modified ZSM-5 on the surface acidity and pore diameter of shape-selective molecular sieve were studied by chemistry liquid deposit method. By the toluene disproportionation reaction, the influences of different modifiers and modified number on the catalytic activities and selectivity of the catalysts were reasearched. The results show that the silica modifier changes the acidity obviously. The novel catalytic performance of modified catalysts attributes to the modification from the silica coverage in the surface and large pore mouth of ZSM-5. The degree of conversion of toluene decreases subtly and the selectivity to xylene improves obviously.