Conversion of Methanol to Hydrocarbons over Ga2O3/H-ZSM-5 and Ga2O3/WO3 Catalysts

• Published in: Journal of catalysis 2002, Vol.205 (2), p.358-365
• Main Authors: Freeman, David, Wells, Richard P.K., Hutchings, Graham J.
• Format: Article
• Language: English
• Subjects: Catalysis; Catalytic reactions; Chemistry; contact synergy; Exact sciences and technology; Ga2O3/H-ZSM-5 catalyst; Ga2O3/WO3 catalyst; General and physical chemistry; methanol conversion to hydrocarbons; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1006/jcat.2001.3446

The conversion of methanol over physical mixtures of Ga2O3 and H-ZSM-5 or WO3/γ-Al2O3 is reported. The addition of Ga2O3 to H-ZSM-5 markedly increases the selectivity to aromatic hydrocarbon at the expense of C2–C4 alkenes, without affecting the overall conversion. This effect is obtained at temperatures ≥400°C, and the maximum effect is observed at 1 : 1 mixtures of Ga2O3 and H-ZSM-5. Experiments using separate beds of Ga2O3 and H-ZSM-5 with different configurations do not reveal any significant effect. In addition, upon removal of Ga2O3 from the Ga2O3/H-ZSM-5 physical mixture the normal catalytic performance of the zeolite is observed. Ga2O3 is also shown to significantly enhance the catalytic activity of a WO3/γ-Al2O3 catalyst when it is incorporated as a physical mixture. The results are explained in terms of a new active site that is formed at the point of contact between Ga2O3 and H-ZSM-5 or WO3/γ-Al2O3 particles. In the case of H-ZSM-5/β-Ga2O3, this site catalyzes the formation of aromatic products from C2–C5 alkenes, whereas for WO3/γAl2O3:β-Ga2O3 the new site catalyzes the formation of methane.