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Background: The alkylation of benzene with methanol is an important synthetic method that is widely used in various chemical production processes. However, obtaining a high selectivity for xylene and annihilating the MTO side reaction remain challenges. Results: In this work, a Ru/HZSM-5 catalyst was prepared using ZSM-5 as the precursor by a chemical precipitation method. Both XRD and TEM confirmed that Ru nanoparticles were evenly dispersed on the surface of the ZSM-5. The catalytic performance of benzene alkylation with methanol on the Ru/HZSM-5 catalyst was investigated. The results showed that the Ru/HZSM-5 catalyst could completely annihilate the MTO side reaction with a high conversion efficiency of benzene and selectivity for xylene, which resulted from the large gap between the transgression energy value of Ru and the ionization potential value of benzene, and the acidity of the catalyst changed greatly. Conclusion: These findings may offer not only a new and efficient multifunctional catalyst for benzene alkylation but also fundamental insight into the catalytic mechanism of the Ru/HZSM-5 catalyst. [ABSTRACT FROM AUTHOR]

The process of benzene/methanol alkylation reaction was studied thermodynamically based on functional group contribution method of Benson. Results show that ortho-xylene (OX), Ethyl-benzene (EB) and tri-methylbenzene (TMB) are the main byproduct in alkylation of benzene by methanol and the suppression of OX, EB and TMB over hierarchical porous HZSM-5 or other types of acidic solid catalysts still remains a great challenge. To overcome these limitations, we modified hierarchical ZSM-5 with ruthenium (Ru) to evaluate the alkylation of benzene with methanol in a fixed-bed continuous flow reactor. It was found that the presence of a small amount of Ru in ZSM-5 catalyst would largely suppress the formation of EB, reduce the selectivity of OX and TMB, and also extend greatly the live time of the catalyst. Alkylation of benzene by methanol: thermodynamics analysis for designing and designing for enhancing the selectivity of toluene and para-xylene.Graphical Abstract: Alkylation of benzene by methanol: thermodynamics analysis for designing and designing for enhancing the selectivity of toluene and para-xylene [ABSTRACT FROM AUTHOR]