Conversion of durene to C9-aromatics compounds by transalkylation with toluene over a mordenite catalyst

• Durene was transalkylated by toluene over H-MOR at 350 °C. • Reaction proceeded mainly by the protonation of durene, which is more basic than toluene. • Durene and toluene conversion is equilibrium limited, but the products were not equilibrated. Methanol-to-hydrocarbons conversion for producing transport fuels also generates durene (1,2,4,5-tetramethylbenzene). Durene falls within the distillate boiling range and is characterized by a high melting point, which can be problematic for blending transport fuels such as diesel fuel and jet fuel. This study investigated the conversion of durene into alternative chemical compounds via the transalkylation of durene with toluene over mordenite (H-MOR), aiming to reduce the durene content in methanol-to-hydrocarbons conversion. By minimizing the durene content, the risk of solidification is reduced. The research focused on evaluating proof of concept by testing durene conversions of 15 and 25 wt% in toluene model feed mixtures at 350 and 450 °C. The acid characterization of H-MOR was determined by NH 3 -TPD and DRIFTS, while TGA was used to determine carbonaceous deposits in the catalyst. The liquid products of the transalkylation reaction were analyzed by gas chromatography. Both Brønsted and Lewis acid sites were identified on the catalyst surface, and catalyst deactivation due to the deposition of carbonaceous material was observed during the study. The chromatograms of liquid products remained consistent at both temperatures and durene-to-toluene ratios. Although the conversion is equilibrium-limited, product equilibrium was not reached within 1 h under reaction conditions. Despite the lower concentration of durene than toluene, the reaction mainly proceeded by the protonation of durene on account of its higher basicity, which was also reflected in the products. Minimal toluene disproportionation was observed, with a low benzene yield (0–2 wt%) compared to a higher yield of xylene isomers (12–26 wt%). The most abundant tri- and tetramethylbenzene isomers were the thermodynamically favoured isomers, namely, 1,2,4-trimethylbenzene and 1,2,3,5-tetramethylbenzene.