Hydroxylation of Benzene to Phenol via Hydrogen Peroxide in Hydrophilic Triethylammonium Acetate Ionic Liquid

A new Fenton-like system in a medium of hydrophilic triethylammonium type of ionic liquid(IL) was used for the hydroxylation of benzene to phenol. The triethylammonium acetate(Et<,3>NH]CH<,3>COO]) IL exhibited re- tardation performance for the decomposition of H<,2>O<,2> and protection performance for the further oxidation of phenol, thus the yield and selectivity to phenol were promoted greatly. The acidity of the system was proved to be an impor- tant factor for the selectivity to phenol. The utilization of H<,2>O<,2> and the selectivity to phenol, as well as the Turnover number(TON) of the catalyst were effectively enhanced by a benzene-Et<,3>NH]CH<,3>COO] bi-phase system. The cata- lyst with Et<,3>NH]CH<,3>COO] IL was recycled with stable catalytic performance.