Friedel-Crafts acylation of 2-methoxynaphthalene over zeolite catalysts

The Friedel-Crafts acylation of 2-methoxynaphthalene was carried out in the liquid-phase batch conditions using H-mordenite, H-beta and H-Y zeolite as catalysts. All the catalysts showed 35-40% conversion in the temperature range of 100-150 degrees C. 1-Acyl-2-methoxynaphthalene was formed as the primary product. When acetyl chloride was used as the acylating agent, a higher yield of 6-acyl-2-methoxynaphthalene was obtained through rearrangement of the sterically hindered l-acyl isomer to the 6-acyl isomer. The presence of extra-framework aluminum in the catalyst facilitates the isomerization of l-acyl isomer to the desired 6-acyl isomer. The final product selectivity was found to be more dependent on the nature of the acylating agents and the reaction temperature and less on the type of the zeolite structure. (C) 2000 Elsevier Science B.V. All rights reserved.