Oxidative coupling of aniline and desulfurization over nitrogen rich mesoporous carbon

Abstract

Tungsten loaded mesoporous nitrogen rich carbon (WO_xMCN_x) materials were synthesized using SBA-15 as a hard template. With these new multifunctional materials, we performed a one-pot oxidative coupling of aniline to azo-benzene followed by desulfurization of dibenzothiophene (DBT) to dibenzothiophene sulfone (DBTSO). It was observed that the nature of the support for the catalyst has a strong influence on the activity of the WO_x nanoparticle. Whilst WO_x on MCN_x proved to be a very active and selective catalyst for the formation of azo-benzene via oxidation of aniline as well as dibenzothiophene sulfone from dibenzothiophene, WO_x on activated carbon or SBA-15 did not show comparable activity. These multifunctional hybrid catalysts retain their structural framework even after the reaction, and they were recovered easily from the reaction mixture through filtration and reused several times without a significant degradation in activity. Moreover, there was no contribution from leached active species in the activity and conversion was possible only in the presence of the multifunctional catalyst.