TRICHLOROLANTHANOID(LnCl3)-CATALYZED FRIEDEL–CRAFTS ALKYLATION REACTIONS

The usual Friedel–Crafts catalysts cannot be re-used after aqueous work-up. An alternative catalyst, based on rare earths has been found, which serves as an efficient Friedel–Crafts catalyst for alkylation of arenes by alkyl halides, and can be re-used after the reaction. Typical examples are shown in the reaction of benzene with benzyl halides using all of the rare earth trichlorides as catalyst, except PmCl3.