The effect of dealumination on the apparent and actual rates of aromatization of methane over MFI-supported molybdenum catalysts

Activity of Oxalic Acid Treated ZnO/CuO/HZSM-5 Catalyst for the Transformation of Methanol to Gasoline Range Hydrocarbons

“…The experimental results indicated that the deactivation resistance of the catalyst may be improved by oxalic acid treatment where the external surface sites were eliminated during dealumination. It has been reported that a catalyst associated with externally dealuminated HZ(Zn/Cu) does not alter by starting deactivation as one associated with unmodified HZ(Zn/Cu) . Since the dealumination is mainly concerned with the external sites, it can also be concluded that the formation of heavier products that need free space are no longer favored.…”

“…It has been reported that a catalyst associated with externally dealuminated HZ(Zn/Cu) does not alter by starting deactivation as one associated with unmodified HZ(Zn/Cu). 21 Since the dealumination is mainly concerned with the external sites, it can also be concluded that the formation of heavier products that need free space are no longer favored. Therefore, the stability against coking could be improved, resulting in apparent improvement of the overall activity under particular circumstances.…”

“…It can be seen from Figure 8 that at higher temperature the peaks of carbon spectra become sharp and more intense due to an increased amount of carbon deposition on the catalyst surface. [21][22][23][24] Carbon deposited on the surface of a catalyst covers the active sites; therefore, sites available for methanol adsorption during methanol to gasoline range hydrocarbons reaction reduce, hence the methanol conversion and hydrocarbon yield decrease.…”

Oligomerization of Biomass-Derived Light Olefins to Liquid Fuel: Effect of Alkali Treatment on the HZSM-5 Catalyst

“…The increase in the strong acid sites not only could promote the oligomerization but also cause side reactions such as cracking or aromatization reactions. Generally, the zeolites with high acid site density are more prone to fast deactivation due to higher coke formation induced by the side reactions and pore blockage caused by diffusion limitation and coke formation. , Thus, the better stability of the alkali-treated HZSM-5 catalysts than the parent HZ catalyst cannot be explained by the increment of acidity. As a consequence, the increase in the strong acid sites density resulting from the alkali treatment mainly contributes to the increased reaction conversion and oligomerization liquid yield of the HZSM-5 zeolite, while the improved catalyst stability should be mainly due to the changes of the zeolite pore structure.…”

Performance of 3%Mo/ZSM-5 catalyst in the presence of water during methane aromatization in supersonic jet expansion

“…1 Methane is a clean source of energy and can be converted to useful chemicals. [2][3][4] According to thermodynamic calculations, 5 the conversion of CH 4 to benzene at equilibrium under nonoxidative conditions is about 12% at 700 C. With cycle processes such as those adopted in chemical industry in mind, one can argue that it is economically feasible to convert methane catalytically to aromatics and hydrogen. However, it is found that catalyst deactivation due to carbon deposition is a major obstacle.…”