HYDROXYLATION OF AROMATICS WITH HYDROGEN-PEROXIDE CATALYZED BY VANADIUM(V) PEROXOCOMPLEXES

Benzene and substituted benzenes XC6H5 (X = CH3, F, Cl, Br, NO2) are h ydroxylated to the corresponding monophenols by H2O2 in CH3CN in the p resence of catalytic amounts of VO (O2) (PIC) (H2O)2 where PIC is the anion of picolinic acid. Fair yields of hydroxylated materials are obt ained by adding the oxidant in portions, or continuously, and keeping the conversion of the substrate rather low (< 3%). Although some degra dation of the catalyst takes place during the reaction, such a process can be minimized by adding small amounts of acid. The catalytic react ion can be also carried out in a two-phase (H2O/dichloroethane) system .