Promoting Xylene Production in Benzene Methylation using Hierarchically Porous ZSM-5 Derived from a Modified Dry-gel Route |
| |
Authors: | Wei Deng Xuan He Chao Zhang Yunyi Gao Xuedong Zhu Kake Zhu Qisheng Huo Zhijie Zhou |
| |
Affiliation: | 1. College of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China;2. State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, China;3. Key Laboratory of Coal Gasification, Ministry of Education, East China University of Science and Technology, Shanghai 200237, China |
| |
Abstract: | Methylation of benzene is an alternative low-cost route to produce xylenes, but selectivity to xylene remains low over conventional zeolitic catalysts. In this work, a combined dry-gel-conversion and steam-assistedcrystallization method is used to synthesize hierarchically porous zeolite ZSM-5 with varied Si/Al malar ratios. X-ray diffraction (XRD), N2 physisorption, NH3-temperature programmed desorption (TPD), scanning electronic microscopic (SEM) measurement and Fourier transforminfrared (FT-IR) are employed to characterize the structure and acidity of both hierarchically porous zeolites and their conventional counterparts. The method is found to be applicable to ZSM-5 with molar ratios of Si/Al from 20 to 180. The ZSM-5 zeolites are used as catalysts for benzene methylation at 460℃ to investigate the effect of additional porosity and Si/Al ratios. At low Si/Al ratios, the benzene conversions over conventional and hierarchical ZSM-5 are close, and selectivity to toluene is high over hierarchical ZSM-5. It is found that hierarchical porositymarkedly enhances the utility of zeolite and the selectivity towards xylenes via improved mass transport at higher Si/Al ratios. Under an optimized hierarchical ZSM-5 catalyst, xylene selectivity reaches 34.9% at a Si/Al ratio of 180. |
| |
Keywords: | Hierarchical zeolite Benzene Methanol Methylation ZSM-5 Process intensification |
本文献已被 ScienceDirect 等数据库收录! |
| 点击此处可从《中国化学工程学报》浏览原始摘要信息 |
|
点击此处可从《中国化学工程学报》下载全文 |
|