Iron-containing graphite as a Friedel-Crafts alkylation catalyst

Article abstract of DOI:10.1006/jcat.2001.3240

The activity of iron-containing graphites for the Friedel-Crafts reaction of phenol with tert-butyl halides was studied. The reaction of phenol with either different tert-butyl halides or tert-butyl alcohol on iron-containing graphite was conducted in a benzene solvent for 4 hr at 50°C. The Friedel-Crafts reaction of phenol with tert-butyl halides on graphite was in the following order: iodide > bromide > chloride. tert-Butyl iodide was the most active in the Friedel-Crafts of phenol in the presence of graphite, whereas it was the least reactive in the presence of AlCl₃. AlCl₃ was very highly active in phenol, while graphite was mildly reactive in phenol. The presence of iron accelerated the reaction of phenol with the tert-butyl halide on graphite to produced p-tert-butylphenol as the main product. The distance between the layers of graphite increased in the presence of both tert-butyl bromide and iron, but not in the presence of either the iron or tert-butyl bromide. tert-Butyl halide was first adsorbed on graphite and then dissociated to form tert-butyl and halogen ions. The Friedel-Crafts alkylation of phenol on graphite was accompanied by isomerization and dealkylation.