A study into the use of microwaves and solid acid catalysts for Friedel-Crafts acetylations

A range of solid acids has been used for the acetylation of methyl salicylate by acetyl chloride/acetic anhydride. A comparison between microwave and traditional heating has been also been made. By comparing alummium chloride, sulfated zirconia, copper triflate on silica, heteropoly tungstic acid on silica and iron(III) chloride on clay (clayfec) a wide ranging comparison has been made and it has been discovered that solid acids can offer truly catalytic acetylations of relatively complex substrates albeit in lower yields than their traditional alternatives such as aluminium chloride. Microwave heating enables lower by-product formation and more importantly reaction times in the order of minutes as opposed to hours required by conventional means. (c) 2004 Elsevier B.V. All rights reserved.