Friedel-Crafts alkylation of anisole in supercritical carbon dioxide: A comparative study of catalysts

The Friedel-Crafts alkylation of anisole with n-propanol was carried out over five different Bronsted. solid acid catalysts using supercritical carbon dioxide as the reaction medium. The reaction temperature and pressure were evaluated in terms of selectivity for the monoalkylated products, conversion of the starting material, and the products' isomeric ratio. Desulfonation of the catalysts was observed when the temperature was increased above 150 degrees C for the organic supported catalysts investigated Amberlyst 15 and Purolite CT-175, and above 200 to 250 degrees C for the inorganic supported catalysts Nafion SAC-13 and Deloxan ASP I/7. A decrease in the catalytic performance of organic supported catalysts was observed with increasing pressure. This decrease was related to the phase behaviour of the reaction.