Selective activation of C H bond of phenol in ortho-position into C OH bond in a two-phase system

A method for the selective activation of CH bond of phenol in ortho-position into C-OH bond was developed at room temperature over Cu2+ ions in a two-phase system using marginally water-soluble polar alcohols, acetonitrile and water as solvents and hydrogen peroxide as an oxidant. In a homogeneous system, phenol was oxidized to produce catechol and 1,4-hydroquinone with a ratio of 0.77:1.0. The addition of alcohols resulted in a two-phase system, and the ratio of catechol and 1,4-hydroquinone was increased to 4.4:1.0. Compared with a homogeneous system, the selectivity for catechol increased for over 5 times in the two-phase counterpart. This offers an effective hydroxylation method for producing catechol from phenol.