METAL-FREE CATALYTIC OXIDATION OF URAZOLES UNDER MILD AND HETEROGENEOUS CONDITIONS VIA COMBINATION OF AMMONIUM NITRATE AND CATALYTIC AMOUNTS OF SILICA SULFURIC ACID

Highly efficient production of 4-substituted-1, 2, 4-triazole-3, 5-diones from urazole derivatives using ammonium nitrate and silica sulfuric acid (SiO₂-OSO₃H), as a cheap and nontoxic catalyst, in the presence of wet SiO₂ (50% w/w) under mild and heterogeneous conditions is reported. The process presented here is operationally simple, environmentally benign and produces high yield.