This proposal requests 6 days of OSIRIS time to conduct QENS measurements on commercial zeolite catalysts which have been removed from a reactor converting methanol to gasoline at various times on stream. The objective is to understand how the diffusion of methanol into the active catalyst is influenced by the presence of hydrocarbon products within the pores, which ultimately result in catalyst deactivation. The proposal forms part of a wider project funded by the EPSRC Catalysis Hub and Johnson-Matthey aimed at understanding the reaction pathways involved in the conversion of methanol. The application is coupled to an INS proposal which aims to speciate the hydrocarbon species in the catalyst.