Swift and selective reduction of nitroaromatics to aromatic amines with Ni-boride-silica catalysts system at low temperature

Various nitroaromatics are successfully reduced to amines with 100% conversion and selectivity in methanol at low temperature (approximate to 5 degrees C), by using versatile system of 5% Ni-SiO2 catalyst and NaBH4 and in situ generation of Ni boride. The catalytic efficiency of Ni loading (5%, 10% and 15%) with silica or titania as support materials is investigated for reduction of nitrobenzene. The Ni-titania/NaBH4 system recorded lower conversion and selectivity. The IR studies indicate that silica support does not have free -OH group on its surface. Thus the nickel boride is anchored to the silica to facilitate the catalytic process.