Durene conversion in a methanol‐to‐jet process: Exploring conversion at 150–350°C over different acid catalysts

Abstract Acid catalyzed conversion of durene by isomerization, disproportionation, and transalkylation is of interest to the development of a methanol‐to‐jet process to reduce the amount of durene in the kerosene. It was of interest to determine whether durene conversion could be performed at a temperature lower than 350°C. As secondary objective, it was of interest to determine to what extent geometric constraints imposed by the acid catalyst affected product distribution. Catalysts with a range of zeolite framework types were employed, in order of increasing pore size: FER, MFI, MOR, BEA, and FAU. All reactions were performed in a batch reactor using a 25 wt.% durene and 75 wt.% toluene feed mixture over the temperature range 150–350°C and autogenous pressure. It was found that durene was more readily converted than toluene due to its higher basicity. Conversion over zeolite catalysts was more related to acid site concentration than acid strength. In zeolites with comparable silica‐to‐alumina ratio (acid strength) the observed activity for durene conversion also increased with increasing pore size (effective diffusivity): FER < MFI < MOR < BEA < FAU. All of the zeolite catalysts were sufficiently constraining to exhibit some product shape‐selectivity. Isomerization (monomolecular reaction) was favoured over disproportionation and transalkylation (bimolecular reactions) in all catalysts. Among zeolites, narrower pores and higher silica‐to‐alumina ratios further favoured monomolecular over bimolecular reactions due to the size and site adjacency requirements of bimolecular reactions.