The reactivity of methanol and methyl acetate mixtures over a HZSM-5 catalyst is studied over a period of 6 h at 350 °C, with small molecular weight olefins and aromatic compounds observed as reaction products. Post-reaction analysis of the catalyst shows the coke content to increase with methyl acetate content. Vibrational spectra (DRIFTS and inelastic neutron scattering, INS) indicate the major hydrocarbon species present in the coked catalysts to be methylated aromatic molecules, with INS spectra indicating a greater degree of methylation in the catalysts used with higher methyl acetate content. The greater extent of deactivation at higher methyl acetate concentrations is tentatively attributed to a diminishment of water in the zeolite cavity, which would otherwise facilitate re-generation of the active sites.
Bibliographical noteFunding Information:
Johnson Matthey plc and the EPSRC are thanked for postgraduate student support (A.P.H., A.Z.) via the Industrial CASE scheme (EP/P510506/1). Johnson Matthey plc is additionally thanked for provision of the ZSM-5 catalyst. The Science and Technology Facilities Council is thanked for the provision of neutron beam time (RB1820116, https://doi.org/10.5286/isis.e.97999822 ). The resources and support provided by the UK Catalysis Hub via Membership of the UK Catalysis Hub Consortium and funded by EPSRC (Grants EP/K014706/1, EP/K014668/1, EP/ K014854/1, EP/K014714/1, and EP/M013219/1) are gratefully acknowledged.
- Inelastic neutron scattering
- Methanol-to-hydrocarbons reaction
- Methyl acetate