Disproportionation of Toluene by Modified ZSM-5 Zeolite Catalysts with High Shape-selectivity Prepared Using Chemical Liquid Deposition with Tetraethyl Orthosilicate  

作　　者：腾晖 王军 任晓乾 陈德民 

机构地区：[1]State Key Laboratory of MateriaIs-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China

出　　处：《Chinese Journal of Chemical Engineering》2011年第2期292-298,共7页中国化学工程学报（英文版）

基　　金：Supported by the Key Natural Science Foundation for Universities of Jiangsu Province（06KJA53012）; the National Natural Science Foundation of China（20776069 20976084）

摘　　要：Shape-selective catalysts for the disproportionation of toluene were prepared by the modification of the cylinder-shaped ZSM-5 zeolite extrudates with chemical liquid deposition with TEOS （tetraethyl orthosilicate）.Various parameters for preparing catalysts were changed to investigate the suitable conditions.The resulting cata-lysts were tested in a pressured fixed bed reactor and characterized by SEM （scanning electron microscopy）.The conversion of toluene and para-xylene selectivity were influenced remarkably by the n（SiO2）/n（Al2O3） ratio of ZSM-5 zeolite,the type and amount of deposition agent,acid and solvent used,and the time and cycle of deposition treatment.TEOS was proved to be a more efficient agent than the conventional polysiloxanes when the deposition amount was low.The catalyst prepared at the suitable conditions exhibited a high para-xylene selectivity of 91.1% with considerable high conversion of 25.6%.SEM analyses confirmed the formation of a layer of amorphous silica on the external surface of ZSM-5 zeolie crystals,which was responsible for the highly enhanced shape-selectivity.为甲苯的 disproportionation 的形状选择的催化剂被塑造柱体的 ZSM-5 沸石 extrudates 的修正与 TEOS (tetraethyl orthosilicate ) 与化学液体免职准备。为准备催化剂的各种各样的参数被改变调查合适的条件。产生催化剂在一个迫使的固定的床反应堆被测试并且由 SEM (扫描电子显微镜学) 描绘了。甲苯和帕拉二甲苯选择的变换被免职代理人，酸和溶剂的 ZSM-5 沸石，类型和数量的 /n (Al2O3 ) 比率使用了的 n (SiO2 ) 显著地影响，并且免职处理的时间和周期。当免职数量是低的时， TEOS 被证明比常规 polysiloxanes 是一个更有效的代理人。以合适的条件准备的催化剂与 25.6% 的可观的高变换展出了 91.1% 的一种高帕拉二甲苯选择。SEM 分析在 ZSM-5 zeolie 晶体的外部表面上证实了非结晶的硅石的层的形成，它为高度提高的形状选择负责。

关 键 词：shape-selective catalysis ZSM-5 zeolite disproportionation of toluene chemical liquid deposition tet-raethyl orthosilicate 

分 类 号：TQ426.6[化学工程] O643.36[理学—物理化学]