Antimony Fluoride Friedel-Crafts reaction

Alkylation of Aromatics. Aromatic hydrocarbons containing a replaceable hydrogen can be alkylated unless steric effects prevent introduction of the alkyl group (61,78-82). The reaction is called the Friedel-Crafts alkylation, first realized in the presence of aluminum chloride, which is the catalyst still the most frequently used and studied in Friedel-Crafts reactions. In addition, many other acid catalysts are effective (80,82-84). These include other Lewis acids (other aluminum halides, gallium chloride, boron trifluoride, ferric chloride, zinc chloride, stannous and stannic chloride, antimony chloride) and protic acids (hydrogen fluoride, concentrated sulfuric acid, phosphoric acid, polyphosphoric acid, trifluo-romethanesulfonic acid, and alkane- and arenesulfonic acids). [Pg.27]

The by far strongest known Lewis acid is antimony pentafluoride, SbFj. Metal fluorides of aluminum, iron, chromium, etc., do not play a prominent role in this context, but instead the chlorides are considered as strong Lewis acids to be used, for example, in Friedel-Crafts reactions. In 1999, Christe et al. [59] introduced the pF scale that provided for the first time a quantification of Lewis acidity strength of metal fluorides and chlorides. Their approach is based on ab initio calculations of the free formation energies of the gas-phase reactions of molecular metal fluorides with a gaseous fluoride anion (Equation (6.11)) ... [Pg.147]

Other catalysts which may be used in the Friedel - Crafts alkylation reaction include ferric chloride, antimony pentachloride, zirconium tetrachloride, boron trifluoride, zinc chloride and hydrogen fluoride but these are generally not so effective in academic laboratories. The alkylating agents include alkyl halides, alcohols and olefines. [Pg.509]