Effect of metal on the methanol to aromatics conversion over modified ZSM-5 in the presence of carbon dioxide

Abstract

Interaction of catalysts' active sites with CO2 affected the aromatics yield of the MTA reaction over modified catalysts in a CO2 atmosphere.

Controlling the product selectivity in the conversion of methanol to the feedstock for phenol production

“…Conte et al 11 observed a signicant decrease in alkenes selectivity while Li et al 13 saw a small reduction in alkenes selectivity. With regard to the p-X byproduct, on all Zn-modied HZSM-5 catalysts, the purity of p-X in xylenes (p-X/X) was around 24.0% except for the 72.4% by Xu et al 10 Silica deposition on HZSM-5 would shi the undesirable m-X, o-X, and nine-or more-nine-carbon higher aromatics (A9+) to the more desirable p-X, as shown in the appendix, Table 7. However, changes in the selectivities for alkanes, alkenes, and P were quite different in these studies.…”

“…In the literatures, the HZSM-5 used for methanol to aromatics contained high amount of Brønsted acid sites (BAS) compared to that of Lewis acid sites (LAS). 3,9,10,13 Zn impregnation on such HZSM-5 decreased BAS and increased LAS significantly. 3,9,10,13 This resulted in an increase in the aromatics selectivity and a decrease in alkanes selectivity.…”

“…3,9,10,13 Zn impregnation on such HZSM-5 decreased BAS and increased LAS significantly. 3,9,10,13 This resulted in an increase in the aromatics selectivity and a decrease in alkanes selectivity. 3,9,10,13 The increase in the aromatic selectivity was attributed to Zn-LAS (ZnOH + ) that could accelerate aromatization and dehydrogenation reactions.…”

“…Among all the metal species, zinc has received considerable attention due to its good selectivity toward aromatics, relatively low cost, and being less toxic. [8][9][10][11][12][13][14][15] In the appendix, Table 7 lists the catalytic performances of HZSM-5, zinc-impregnated HZSM-5 (Zn/ HZSM-5), silica-deposited HZSM-5 (Si/HZSM-5), and zincimpregnated silica deposited HZSM-5 (Zn/Si/HZSM-5) found in the literatures. The impregnation of Zn on HZSM-5 in general increased aromatics selectivity and decreased alkanes (methane, ethane, propane, butanes) selectivity.…”

Insight into the Formation of COX By‐Products in Methanol‐to‐Aromatics Reaction over Zn/HZSM‐5: Significantly Affected by the Chemical State of Surface Zn Species

“…[1][2][3] HZSM-5 zeolite is regarded as the most appropriate catalytic-material for this process, because of its adjustable acidic properties, high hydrothermal stability and regular three-dimensional 10-ring pore matching with the light aromatic molecules. [1][2][3] HZSM-5 zeolite is regarded as the most appropriate catalytic-material for this process, because of its adjustable acidic properties, high hydrothermal stability and regular three-dimensional 10-ring pore matching with the light aromatic molecules.…”