Friedel-Crafts type reactions zeolite catalysts

A remarkable synthesis of oxalate salts using a supercritical mixture of CO2 and CO under very drastic conditions (400 bar, 380°C) in the presence of solid 082(003) was reported [71]. Friedel-Crafts-type alkylations on zeolites [72] or other solid acid catalysts [73] have been studied using SCCO2 as the medium. Performing the reaction in the supercritical state was found to be superior to either liquid or gas phase processes. Using scCOj lead to enhanced catalyst life-... 

In this chapter, the use of solid acids as heterogeneous catalysts for the Friedel-Crafts acylahon reaction is described. Our review is split up into seven sechons, describing the application of zeolites, clays, metal oxides, sulfated zirconia, heteropoly acids. Nation, and other less-utilized solid catalysts (i.e., graphite). When possible, the relationship between the acid properhes of the solids (namely, Bronsted and Lewis types) and the catalytic efficiency is shown, as well as the role of the active site location on the catalyst surface. ... 

Alkylations are Friedel-Crafts-type electrophilic reactions requiring the participation of a strong Lewis catalyst. Obviously they were carried out in the presence of hazardous Lewis acid catalysts as metal halides. Switching from these molecular compounds to solid embedded triflates led to catalysts on which such reactions occurred with turnover frequency (TOFs) having at least one order of magnitude higher than on classic acid solid catalysts as zeolites [100,101]. Examples of such reactions are alkylations of phenols or naphthols occurring on immobilized La, Ag, or r rr-butyldimethylsilyl-trifluoromethane-sulfonate catalysts. 

---