低碳烷烃芳构化反应机理研究进展  

Research Progress in the Mechanism of Light Alkane Aromatization

作　　者：吴冰峰 王子健[1] 马爱增[1] 于中伟[1] 代振宇[1] WU Bingfeng;WANG Zijian;MA Aizeng;YU Zhongwei;DAI Zhenyu(Research Institute of Petroleum Processing,SINOPEC,Beijing 100083,China)

机构地区：[1]中国石化石油化工科学研究院,北京100083

出　　处：《石油学报（石油加工）》2021年第3期690-699,共10页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：中国石油化工股份有限公司课题(120053-3)资助。

摘　　要：将低碳烷烃芳构化反应途径划分为烷烃活化和烯烃芳构化两部分。介绍了烷烃在催化剂表面B酸位上活化的Haag-Dessau机理和经典裂化机理,在低转化率、高反应温度、低反应物分压时,烷烃主要通过Haag-Dessau机理活化。简述了烷烃在L酸位上活化过程,分析表明该过程符合B-L酸协同活化特征。分别介绍了烯烃芳构化过程中齐聚、裂化和环化的反应机理,指出在酸性位上完成的这些反应都基于正碳离子机理。其中齐聚反应受空间位阻的限制,尺寸过大的齐聚体较难生成,β-裂化速率与异构后β-C原子的电荷量有关,在配位数相同时,电荷量越多越容易裂化,环化反应与醇盐中间体的类型有关,1,6闭环和1,5闭环均有可能发生。展望了低碳烷烃芳构化机理研究的发展方向。In this work, two major pathways of light alkane aromatization, including alkane activation and alkene aromatization, was reviewed. The Haag-Dessau mechanism and classical cracking mechanism of alkane activation by Bronsted acid sites of catalysts were introduced. Alkanes are mainly activated by the Haag-Dessau mechanism at low conversion, high reaction temperature and low reactant partial pressure. The activation process of alkanes over Lewis acid sites was described. The process is consistent with the characteristics of synergistic activation by Bronsted acid and Lewis acid. The reaction mechanisms of oligomerization, cracking and cyclization during the aromatization of olefins were introduced respectively. These reactions are completed with aromatization on the Bronsted acid site, owing to the formation carbenium species. Due to the steric hindrance of channels of zeolites, oligomers of large size are difficult to be generated. The β-cracking rate depends on the charge of β-C atoms after isomerization. Under the same coordination condition, the β-cracking rate is increasing along with the increase of charge amount. As for the cyclization reaction, both 1,6-ring closure and 1,5-ring closure reaction may occur, and the way of cyclization is determined by the type of alkoxide complex. Finally, the development direction of light alkanes aromatization mechanism is prospected.

关 键 词：烷烃 芳构化 ZSM-5 反应机理 

分 类 号：TE624[石油与天然气工程—油气加工工程]