Selective oxidation of anilines to azobenzenes by an Ag nanoparticles photocatalyst

Azobenzenes play an important role in dyes and pigments, food additives and pharmaceuticals. However, selective oxidation of aniline to valuable azobenzene under mild conditions is considerably challenging. Herein, through the reduction of boron clusters loaded with layered double hydroxides (LDHs), a nanometallic photocatalyst ZnTi LDH@ [ closo -B 12 H 12 ]@ 1.17%Ag(ZnTi LDH@B 12 H 12 @Ag) was synthesized. The catalyst catalyzed the synthesis of azobenzene from aniline. The catalyst achieved a high turnover frequency (TOF) of 54.9 h −1 and turnover number (TON) of 439.3. Under the reaction conditions of Na 2 CO 3 , at 40 °C and irradiation at 365 nm with an ultraviolet light source at atmospheric pressure, the yield of azobenzene reached 95.3% after 8 h of reaction and the catalytic activity remained above 80% after six recycles. This study reports a new synthetic catalyst for the selective oxidation of aniline compounds to azobenzene.