Fe(III), Cu(II), V(V)/TiO₂ for Hydroxylation of Benzene to Phenol with Hydrogen Peroxide at Room Temperature

Abstract

The hydroxylation of benzene to phenol with hydrogen peroxide catalyzed by transition metal (Fe(III), Cu(II), and V(V)) on a TiO₂ support was performed at room temperature. The Fe(III) catalyst gave the highest conversion and yield but showed the lowest selectivity. At room temperature, the phenol yield was quite low and therefore modifying the system by solvent addition or operation under UV light was examined. Among the various solvents studied, i.e., acetone, acetronitrile and pyridine, acetone gave the highest conversion and yield; however, the selectivity was low. Acetonitrile is a suitable solvent in terms of improved selectivity and yield. Operation under UV light significantly improved the yield with comparatively high selectivity. Ascorbic acid, as a reducing agent, was able to improve the phenol yield. In some solvent systems, an optimum amount of ascorbic acid was observed.