Understanding Elementary Steps of Transport of Xylene Mixtures in ZSM-5 Zeolites
Understanding Elementary Steps of Transport of Xylene Mixtures in ZSM-5 Zeolites
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DOI：
10.1021/acs.jpcc.8b07348
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发表时间：
2019-04-04
影响因子：
3.7
通讯作者：
Lercher, Johannes A.
中科院分区：
文献类型：
--
作者：
Baumgaertl, Martin;Jentys, Andreas;Lercher, Johannes A.
采用快速时间分辨红外光谱和频率响应方法研究了间二甲苯共吸附时对二甲苯在纯硅质MFI中的迁移行为。在MFI的直通道中，对二甲苯的传输速率主要由扩散控制，其比正弦通道中的传输快8倍。吸附在外表面上的间二甲苯通过阻塞孔入口而显著降低对二甲苯的吸附速率，而吸附在MFI孔中的间二甲苯几乎不影响对二甲苯的传输速率。如果孔入口是传输过程的速率决定步骤，对于所研究的MFI样品，外表面上的间二甲苯吸附选择性地阻碍通过直孔开口的更快传输
The transport of p-xylene in purely siliceous MFI was investigated in the presence of coadsorbed m-xylene by combining fast time-resolved IR spectroscopy and frequency response methods. p-Xylene transport rates are dominated by diffusion in the straight channels of MFI, which is 8 times faster than transport in the sinusoidal channels. m-Xylene adsorbed on the outer surface lowers the sorption rate of p-xylene significantly by blocking pore entrances, whereas m-xylene adsorbed in the MFI pores hardly influences the p-xylene transport rates. If the pore entrance is the rate-determining step of the transport process, as for the MFI samples investigated, m-xylene sorption on the outer surface selectively impedes faster transport through the straight pore openings