期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
Effect of external surface of HZSM-5 zeolite on product distribution in the conversion of methanol to hydrocarbons 被引量:3
1
作者 Junhui Li Yanan Wang +4 位作者 wenzhi jia Zhiwen Xi Huanhui Chen Zhirong Zhu Zhonghua Hu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2014年第6期771-780,共10页
The external surface of HZSM-5 zeolite was passivated by liquid siliceous deposition and by acidic sites poisoning with lepidine, respectively. Then methanol-to-hydrocarbons (MTH) reaction was investigated over the ... The external surface of HZSM-5 zeolite was passivated by liquid siliceous deposition and by acidic sites poisoning with lepidine, respectively. Then methanol-to-hydrocarbons (MTH) reaction was investigated over the above as-prepared catalysts and the dissoluble coke on these used catalysts was analyzed by GC-MS, to study the role of the external surface of HZSM-5 in the catalytic reaction. Comparison with the experi- mental results based on parent ZSM-5 showed that the product distribution of MTH reaction was obviously influenced by the external surface. Evidences were listed as follows: (1) the final product on parent HZSM-5 showed higher aromatic selectivity, lower olefin selectivity, lower ra- tio of C2/C3+ aliphatics and higher ratio of C3/C4+ aliphatics than the reaction mixture produced by the sole catalysis of acidic sites in HZSM-5 channel; (2) a little of pentamethylbenzene and hexamethylbenzene in the product on parent HZSM-5, was produced via multi-methylation of methylbenzene on the external surface. The above conclusion may also be suitable for MTH reaction over other zeolites with 10-ring channel. 展开更多
关键词 METHANOL-TO-HYDROCARBONS product distribution HZSM-5 external surface acidic sites
下载PDF
Influence of Metallic Modification on Ethylbenzene Dealkylation over ZSM-5 Zeolites 被引量:5
2
作者 Chao Hu Junhui Li +3 位作者 wenzhi jia Min Liu Zhixian Hao Zhirong Zhu 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2015年第2期247-252,共6页
A series of metal-modified HZSM-5 catalysts were prepared by impregnation and were used for ethylbenzene dealkylation of the mixed C8 aromatics(ethylbenzene,m-xylene and o-xylene).The effects of different supported me... A series of metal-modified HZSM-5 catalysts were prepared by impregnation and were used for ethylbenzene dealkylation of the mixed C8 aromatics(ethylbenzene,m-xylene and o-xylene).The effects of different supported metals(Pt,Pd,Ni,Mo)on catalytic performance,including reaction conditions,were investigated.The physicochemical properties of catalysts were characterized by means of XRD,BET,TEM and NH_(3)-TPD.Experimental results showed that metallic modification obviously increased the ethylbenzene conversion and reduced the coke deposition,greatly improving the catalyst stability.The distinction of ethylbenzene conversion depended on the interaction between hydrogenation reactivity and acidic cracking of bifunctional metal-modified zeolites.Compared with Pt and Ni,Pd and Mo were easier to disperse into HZSM-5 micropores during loading metals.The acidic density of different metal-modified HZSM-5 declined in the following order:HZSM-5>Pt/HZSM-5>Pd/HZSM-5>Ni/HZSM-5>Mo/HZSM-5.The activity of ethylene hydrogenation decreased with Pt/HZSM-5>Pd/HZSM-5>Ni/HZSM-5>Mo/HZSM-5.In comparison,Pd/HZSM-5 showed the best catalytic performance with both high activity and high selectivity,with less cracking loss of m-xylene and o-xylene.Moreover,the following reaction conditions were found to be preferable for ethylbenzene dealkylation over Pd/HZSM-5:340℃,1.5 MPa H2,WHSV 4 h^(−1),H_(2)/C84 mol/mol. 展开更多
关键词 ETHYLBENZENE DEALKYLATION zeolites PALLADIUM
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部