Highly Efficient Production of Benzene-Free Aromatics from Methanol over Low-Si/Al-Ratio Alkali-Modified Fe/Zn/HZSM-5

Abstract

Herein, the methanol conversion to aromatic hydrocarbons was studied over a new family of mesoporous low-silica HZSM-5 (Si/Al = 11) catalysts in a fixed-bed tubular reactor under ambient pressure at 375 °C, feeding with weight hourly space velocity of 2 h –1 . The catalysts were prepared in the absence and presence of Zn and Fe in both alkaline and neutral aqueous solutions, characterized by using X-ray diffraction, X-ray fluorescence, temperature programmed desorption of ammonia, N 2 adsorption/desorption, thermogravimetric analysis, Fourier-transform infrared, transmission electron microscopy (TEM), field emission scanning electron microscopy and FE-SEM/energy dispersive X-ray spectroscopy techniques. The [0.2Fe,0.3Zn]-alk-HZSM-5 catalyst exhibited novel selectivity for aromatics (>86 wt %), specifically for m and p -xylenes (44.7 wt %) alongside 0.1 wt % for benzene.

Effect of Si/Al ratio of high-silica HZSM-5 catalysts on the prins condensation of isobutylene and formaldehyde to isoprene

“…1. Distinct diffraction peaks were detected in the 2θ ranges of 7-10 as well as 20-25, which is consistent with the reports in literature, indicating that all zeolites exhibit MFI topology with high crystalline purity [14,15,16,17].…”

High-Impact Promotional Effect of Mo Impregnation on Aluminum-Rich and Alkali-Treated Hierarchical Zeolite Catalysts on Methanol Aromatization

“…To determine the zeolite performance in the MTA process, a fixed-bed tubular reactor was employed under ambient pressure . The reaction temperature was set at 375 °C in these experiments, while a graduated burette equipped with a microtube pump (prep pump, Chem Tech Co. Ltd.) was used for methanol injection (WHSV of 2 h –1 ).…”

“…Recently, we carried out a comparative study on both alkali treatment and Fe–Zn postmodification of low-Si/Al HZSM-5 zeolite, employed in aromatics production in the MTA reaction . The result was successful in terms of the achievement of novel aromatics selectivity of [0.2Fe,0.3Zn]-alk-HZSM-5.…”

“…Recently, we carried out a comparative study on both alkali treatment and Fe−Zn postmodification of low-Si/Al HZSM-5 zeolite, employed in aromatics production in the MTA reaction. 55 The result was successful in terms of the achievement of novel aromatics selectivity of [0.2Fe,0.3Zn]alk-HZSM-5. As an unstudied case in the MTA reaction, it convinced us to undertake a comparative study of Mo impregnation as a new single-component post-treatment on low-Si/Al HZSM-5.…”

Realization of rapid synthesis of H-ZSM-5 zeolite by seed-assisted method for aromatization reactions of methanol or methane

“…Aromatic hydrocarbons are important chemical intermediates in fine chemical industry, which have huge industrial demand. 1 In recent decades, the methanol to aromatics (MTA) and methane to benzene (MTB) reaction over solid acid catalysts have attracted the attention of scientists and industrial organizations, because methanol is provided by different resources, such as natural gas, coal, biomass and any other carbon-based gasifiable raw materials as well as methane is provided by shale gas. [2][3][4] H-ZSM-5 zeolite is widely applied to some solid acid catalytic processes, such as MTB reaction and MTA reaction, due to its adjustable acidity, thermal stability and a special porous structure of 5.3 × 5.6 Å and 5.1 × 5.5 Å.…”