Coupling of Methanol and Carbon Monoxide over H‐ZSM‐5 to Form Aromatics

Abstract

The conversion of methanol into aromatics over unmodified H-ZSM-5 zeolite is generally not high because the hydrogen transfer reaction results in alkane formation. Now circa 80 % aromatics selectivity for the coupling reaction of methanol and carbon monoxide over H-ZSM-5 is reported. Carbonyl compounds and methyl-2-cyclopenten-1-ones (MCPOs), which were detected in the products and catalysts, respectively, are considered as intermediates. The latter species can be synthesized from the former species and olefins. C isotope tracing and C liquid-state NMR results confirmed that the carbon atoms of CO molecules were incorporated into MCPOs and aromatic rings. A new aromatization mechanism that involves the formation of the above intermediates and co-occurs with a dramatically decreased hydrogen transfer reaction is proposed. A portion of the carbons in CO molecules are incorporated into aromatic, which is of great significance for industrial applications.

Highly Enhanced Aromatics Selectivity by Coupling of Chloromethane and Carbon Monoxide over H‐ZSM‐5

“…Figure 1c depicts the change on aromatic formation rate with CO pressure during CH 3 Cl conversion. The rate of aromatics rings formation increases monotonically with increasing CO partial pressure, implying that the formation of aromatics is closely related to CO similar with the coupling of small molecule compounds and CO [3d, 16] . In addition, the trends in selectivity to C 2 –C 4 alkanes (from 22.2 to 3.1 %) and olefins (from 23.6 to 5.6 %) are opposite to that of aromatics (from 39.0 to 79.3 %) with increasing partial pressure of CO (Figure S2).…”

Hydrogenation of CO2 into aromatics over ZnZrO–Zn/HZSM-5 composite catalysts derived from ZIF-8

“…A number of investigations of the reaction mechanism of the transformation of oxygenated hydrocarbons over zeolite catalysts have been carried out. 2,[48][49][50] The "hydrocarbon pool" mechanism proposed by Dahl et al is widely accepted at present, 51,52 and there was a dual-cycle reaction pathway based on aromatics and olefins. 53,54 Heavy aromatics and olefins were used as reaction intermediates to repeatedly undergo dealkylation, cracking, oligomerization, cyclization and dehydrogenation reactions to generate low-carbon aromatics.…”

ZnO Supported on a Zr-Based Metal–Organic Framework for Selective CO2 Hydrogenation to Methanol

“…1 As methanol is a potential clean fuel and an important feedstock chemical, 2,3 catalytic conversion of CO 2 to methanol (MeOH) is a highly desirable chemical process. Methanol can be dehydrated to dimethyl ether, 4−7 used to synthesize hydrocarbons, 8−14 such as olefins, 15−18 aromatics, 19,20 and gasoline, 21,22 and coupled to produce ethylene glycol. 23,24 Much effort has been made in the development of supported metal catalysts for CO 2 hydrogenation; 25−30 ZrZn catalysts were widely studied for MeOH production, 31−35 including ZnO−ZrO 2 mixed metal oxides, 31 ZnO−ZrO 2 aerogels, 32 and ZnO−ZrO 2 solid solutions.…”

“…As methanol is a potential clean fuel and an important feedstock chemical, , catalytic conversion of CO 2 to methanol (MeOH) is a highly desirable chemical process. Methanol can be dehydrated to dimethyl ether, − used to synthesize hydrocarbons, − such as olefins, − aromatics, , and gasoline, , and coupled to produce ethylene glycol. , …”