Influence of temperature on the product selectivity and distribution of aromatics and C₈ aromatic isomers in the conversion of dilute ethene over H-galloaluminosilicate (ZSM-5 type) Zeolite

Abstract

Product selectivity and distribution of the total and C₈ aromatics at the different isoconversions (40, 60, and 80%) of dilute ethene (5 mol% C₂H₄ in N₂) over the H-GaAlMFI zeolite catalyst at different temperatures (300-500° C) have been investigated. A strong temperature dependence of the selectivity for aromatics, propene, and C₄ hydrocarbons and also of the distribution of aromatics and C₈-aromatic isomers has been observed. At lower temperatures (below 400° C) the aromatization involved mainly hydride transfer reactions, but at higher temperatures (=400° C) it involved mainly dehydrogenation reactions. The distribution of xylene isomers is controlled by steric factors at 300° C but kinetically at 500° C.