Acylation of Toluene with Acetic Anhydride on beta Zeolites

摘要

Substituted arylketones are very important intermediates for the manufacture of valuable chemicals such as drugs, fragrances, dyes, and pesticides. They are usually synthesized through Friedel-Crafts acylation with acid chlorides or anhydrides in the presence of acid catalysts of Bronsted or Lewis type. Recent developments concern the use of zeolite catalysts, which could be an alternative for a more environmentally friendly and noncorrosive process without the release of acidic catalyst components, aggressive gases and corrosive solutions. The zeolites showed promising catalytic behaviour for the Friedel-Crafts reactions, and Andy et al. have reported an industrial application of zeolites catalyst in aromatic ketone synthesis by acylation. Although the acylation of phenols and aromatic ethers with alkyl/aryl chlorides over zeolites could give good yields and selectivities, the results of that for less active aromatic rings like toluene and benzene are not satisfied. Moreover, the rapid deactivation of zeolite catalysts due to coke deposition in the micropores is still an essential problem.