Silica Sulfuric Acid/ NaNO(2) as a Novel Heterogeneous System for the Nitration of Phenols under Mild Conditions

Nitrophenols can be obtained in moderate to high yields via nitrosation-oxidation of phenols with silica sulfuric acid, NaNO(2) and wet SiO(2) at room temperature. In situ generation of HNO(2) and a radical cation mechanism via the nitrous acid catalyzed (NAC) pathway appear to be applicable to phenol nitration using these reagents.