Oxidation of Aniline to Nitrobenzene Catalysed by 1-Butyl-3-methyl imidazolium phosphotungstate Hybrid Material Using m-chloroperbenzoic Acid as an Oxidant

Keggin ion based hybrid materials, [BmIm] 3 [PW 12 O 40 ], [TBA] 3 PW 12 O 40 and [BuPy] 3 PW 12 O 40 , were prepared by proton exchange with organic cations, 1-butyl-3-methyl imidazolium ion, tetrabutylammonium ion and butylpyridinium ion, respectively. The formation of hybrid materials was confirmed by FTIR, PXRD, SEM, TG-DTA, DSC analysis. These hybrid compounds are active for oxidation of aniline using m-chloroperbenzoic acid as an oxidant. Among the three hybrid compounds, 1-butyl-3-methyl imidazolium phosphotungstate was found to be the best and efficient catalyst for selective aniline oxidation to nitrobenzene. It is a recoverable and reusable catalytic system. The redox property of the phosphotungstate cluster in the hybrid material is involved in the catalytic activity. Graphical Abstract