硅油-硝酸镧复合改性ZSM-5催化剂上甲苯甲醇选择性烷基化反应性能  

Selective alkylation of toluene with methanol over HZSM-5 zeolite modified by lanthanum nitrate and silicone oil

作　　者：邹薇[1,2] 黄翩翩[1] 管卉[1] 祁晓岚[1] 孔德金[1] 乐英红[2] 

机构地区：[1]中国石油化工股份有限公司上海石油化工研究院,上海201208 [2]复旦大学化学系上海市分子催化和功能材料重点实验室,上海200433

出　　处：《工业催化》2014年第9期671-675,共5页Industrial Catalysis

基　　金：国家重点基础研究发展计划(973计划)(2009CB623501)资助项目

摘　　要：以HZSM-5为改性基体,甲基硅油为改性剂,采用浸渍法制备硅油改性催化剂SiHZ(3.0)和复合改性催化剂SiHZ(3.0)/La2O3,考察硅油-硝酸镧复合改性ZSM-5催化剂上甲苯甲醇选择性烷基化的反应性能,并与单纯硅油改性的ZSM-5催化剂进行比较,结合催化剂酸性和孔结构的表征,研究硅油-硝酸镧复合改性对催化剂性能的影响。结果表明,在反应初期复合改性SiHZ(3.0)/La2O3催化剂上,甲苯转化率略低于单纯硅油改性的SiHZ(3.0)催化剂,对二甲苯选择性相近;反应100 h后,SiHZ(3.0)/La2O3催化剂活性和选择性均高于SiHZ(3.0)催化剂,说明复合改性催化剂中La2O3在硅油修饰外表面和孔口的基础上,进一步调变孔道内酸性质,降低强酸中心量和B酸酸量,从而显著提高催化剂稳定性。Through modification of HZSM-5 zeolite catalysts by chemical liquid depositon of methyl silicone oil,SiHZ（3. 0） catalysts was prepared,and SiHZ（3. 0） /La2O3 catalysts was further prepared after impregnation by lanthanum nitrate. The catalytic performance of the catalysts for toluene selective alkylation with methanol to p-xylene were evaluated. The catalytic behavior of the catalysts was further studied with characterization methods such as BET,NH3-TPD and IR pyridine-adsorption spectroscopy. The results of a 100 h pilot test exhibited that SiHZ（3. 0） /La2O3 catalyst had lower initial methylation activity but much higher stability than SiHZ（3. 0） catalyst,and the selectivity to p-xylene over both catalysts was similar. The activity and selectivity of SiHZ（3. 0） /La2O3 catalyst were higher than those of SiHZ（3. 0）catalyst after reaction for 100 h,which indicated that the enhanced stability could be ascribed to the decrease of acidic sites of strong acid and Brnsted acid on the internal surface of the zeolite crystallites by La2O3 modification,resulting in suppression of coke formation which was thought to be the main cause for the catalyst deactivation.

关 键 词：催化化学 甲苯甲醇选择性烷基化 HZSM-5 复合改性 择形催化 LA2O3 硅油 

分 类 号：TQ426.6[化学工程] O643.36[理学—物理化学]