Theoretical studies on the reaction mechanisms of AlOOH- and γ-Al2O3-catalysed methanol dehydration in the gas and liquid phases

The influence of the liquid environment on the reaction mechanism in slurry reactors has not been fully investigated. In this work, dimethyl ether (DME) synthesis from methanol dehydration over γ-Al2O3 (1 1 0) and AlOOH (1 0 0) in liquid paraffin and in the gas phase is studied using density functional theory combined with the conductor-like solvent model. The liquid paraffin can influence surface relaxation, Mulliken charges, and adsorptive behavior of γ-Al2O3 and AlOOH. For DME synthesis, liquid paraffin does not influence the reaction path over the γ-Al2O3 surface, but influences its activation energy. Liquid paraffin influences the activation energy and also alters the reaction path of DME synthesis over AlOOH

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► DFT-COSMO method was used to examine DME synthesis from methanol dehydration.
► The activation energies of limiting step of DME synthesis over γ-Al2O3 is higher than that of over AlOOH.
► Liquid phase environment can influence γ-Al2O3 and AlOOH surfaces relaxation, surface energies and Mulliken charges.
► Liquid phase environment can influence adsorptive behavior and reactive path of DME synthesis over γ-Al2O3 and AlOOH surfaces.