The acylation of 2-methoxynaphthalene with acetic anhydride over Nafion/silica composites and BEA zeolites containing Lewis acid sites

• Published in: Applied catalysis. A, General Vol. 350; no. 1; pp. 1 - 5
• Main Authors: Schuster, H., Hölderich, W.F.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.11.2008; Elsevier
• Subjects: 2-Methoxynaphthalene; Catalysis; Chemistry; Exact sciences and technology; Friedel-Crafts acylation; General and physical chemistry; Ion-exchange; Nafion/silica composites; Naproxen; Solvents; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Zeolites; Zeolites: preparations and properties; Solvents; Friedel-Crafts acylation; Nafion/silica composites; 2-Methoxynaphthalene; Zeolites; Naproxen; Nitro compound; Binary compound; Acidic site; Metal ion; Selectivity; Liquid phase; Silica; Molecular sieve; Composite material; Chlorine compounds; Ion exchange; Acylation; Lewis acid; Catalytic reaction; Lewis site; Hydrocarbon; Polar solvent; Fluorine containing polymer; Toluene; Zeolite; Conversion; Sulfonate polymer; Heterogeneous catalysis; Dichloromethane; Benzenic compound
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2008.07.026

The authors have investigated the use of Nafion/silica composite materials with Nafion contents ranging from 5 to 80 wt% and the influence of different solvents in the acylation of 2-methoxynaphthalene. It was found that the yield of desired product (2-acetly-6-methoxynaphthalene) increased both with increasing Nafion content of the catalyst and solvent polarity. Further experiments were performed with metal ion-exchanged Nafion/silica composite materials and – for comparison reasons – zeolite H-BEA and metal doped H-BEA. ▪ The influence of Nafion content (5–80 wt%) in different Nafion/silica composite materials (SAC) as well as the effect of different solvents was studied in liquid phase Friedel-Crafts acylation of 2-methoxynaphthalene (2-MN) with acetic anhydride. The higher the Nafion content, the higher are conversion and selectivity (up to 69%) to the desired product 2-acetyl-6-methoxynaphthalene (2,6-ACMN). Unpolar solvents such as toluene or methylene chloride favour the formation of 1-acetyl-2-methoxynaphthalene (1,2-ACMN) while polar solvents like nitrobenzene or sulfolane promote the 2,6-ACMN formation. Further investigations are related to the influence of metal ions, e.g. Al 3+, Fe 3+, Zn 2+, Cu 2+ and Ag + in ion-exchanged Nafion–silica composite on the formation of the desired 2,6-ACMN. An increase in selectivity to 2,6-ACMN in comparison with the pure acidic Nafion–silica was observed. Zeolites containing Lewis acid sites created by ion-exchange with Fe 3+, Cu 2+ and Ag + were investigated in the heterogeneously catalysed acylation of methoxynaphthalene for comparison reasons.