In Situ Aluminum Migration into Zeolite Framework during Methanol-To-Propylene Reaction: An Innovation To Design Superior Catalysts
发表时间：2019-03-12
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- 论文类型：
- 期刊论文
- 第一作者：
- Li, Junjie
- 合写作者：
- Liu, Min,Guo, Xinwen,Dai, Chengyi,Xu, Shutao,Wei, Yingxu,Liu, Zhongmin,Song, Chunshan
- 发表时间：
- 2018-06-20
- 发表刊物：
- INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
- 收录刊物：
- SCIE
- 文献类型：
- J
- 卷号：
- 57
- 期号：
- 24
- 页面范围：
- 8190-8199
- ISSN号：
- 0888-5885
- 摘要：
- This work involves methanol-to-propylene (MTP) conversion over aluminosilicate MFI (ZSM-5), borosilicate MFI (B-ZSM-5), and all-silica MFI (Silicate-1). Both B-ZSM-5 and Silicate-1 were inactive in MTP reaction. However, extruded Silicate-1 sample prepared by extrusion with Al2O3 binder, followed by acid washing treatment, displayed a rapid increase in methanol conversion in the initial 30 h time on stream (TOS), and then retained 99% methanol conversion, higher propylene selectivity (52.2%), and higher propylene/ethylene ratio (11.3) for 400 h TOS. Silicate-1 modified with AlCl3 or Al(NO3)(3) showed similar catalytic performance as the extruded samples. Several AlCl3 -modified Silicate-1 samples after various TOS values were regenerated and characterized by NH3 -termperature-programmed desorption (TPD), Fourier transform infrared (FT-IR) spectroscopy, and Al-22 magic angle spinning nuclear magnetic responance (MAS NMR). The results point to continuous aluminum insertion into Silicate-1 framework during reaction in situ, which rationalizes the superior catalytic performance. By analyzing catalytic performances of AlCl3-modified samples with different amounts of defect sites, we concluded that Al migration is related to the defect sites. Finally, a catalyst with a much longer lifetime of 960 h and 53.2% propylene selectivity was developed by incorporating Al migration into hierarchical samples.
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