Co-conversion of methanol and
Shumei Wei, Yarong Xu, Zhaoyang Jin, Xuedong Zhu
Frontiers of Chemical Science and Engineering
2020,
Volume 14,
Issue 5,
Pages 783-792
doi:
10.1007/s11705-019-1868-2
Abstract:
The conversion of -hexane and methanol into value-added aromatic compounds is a promising method for their industrially relevant utilization. In this study, intergrown ZSM-5/ZSM-11 crystals were synthesized and their resulting catalytic performance was investigated and compared to those of the isolated ZSM-5 and ZSM-11 zeolites. The physicochemical properties of ZSM-5/ZSM-11 intergrown zeolite were analyzed using X-ray diffraction, N isothermal adsorption-desorption, the temperature-programmed desorption of ammonium, scanning electron microscopy, Fourier transform infrared spectra of adsorbed pyridine, and nuclear magnetic resonance of Al , and compared with those of the ZSM-5 and ZSM-11 zeolites. The catalytic performances of the materials were evaluated during the co-feeding reaction of methanol and -hexane under the fixed bed conditions of 400°C, 0.5 MPa (N ), methanol꞉ -hexane= 7꞉3 (mass ratio), and weight hourly space velocity= 1 h (methanol). Compared to the ZSM-5 and ZSM-11 zeolites, the ZSM-5/ZSM-11 zeolite exhibited the largest specific surface area, a unique crystal structure, moderate acidity, and suitable Brønsted/Lewis acid ratio. The evaluation results showed that ZSM-5/ZSM-11 catalyst exhibited better catalytic reactivity than the ZSM-5 and ZSM-11 catalysts in terms of methanol conversion rate, -hexane conversion rate, and aromatic selectivity. The outstanding catalytic property of the intergrown ZSM-5/ZSM-11 was attributed to the enhanced diffusion associated with its unique crystal structure. The benefit of using zeolite intergrowth in the co-conversion of methanol and alkanes offers a novel route for future catalyst development.
Keywords：
ZSM-5/ZSM-11
methanol
n-hexane
cofeeding
aromatics
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