Journal of Catalysis, Vol.389, 241-246, 2020
Efficient chemoselective hydrogenation of nitrobenzene to aniline, azoxybenzene and azobenzene over CQDs/ZnIn2S4 nanocomposites under visible light
Efficient production of amino-, azo- and azoxyaromatics is important in chemical industries. In this manuscript, we reported that controllable chemoselective hydrogenation of nitrobenzene to produce aniline, azoxybenzene and azobenzene was realized over CQDs/ZnIn2S4 nanocomposite under visible light via simply regulating the reaction medium including the alkalinity and the hydrogen source. An optimized production of aniline was obtained over 3.0 wt% CQDs/ZnIn2S4 nanocomposite in a reaction medium of TEOA: MeOH (1:1), while a strong alkaline reaction medium promote N-N coupling to produce azoxybenzene and azobenzene. In addition, azoxybenzne is the intermediate to form azobenzene during the hydrogenation of nitrobenzene, in which a strong hydrogen source like TEOA is indispensable for the transformation. This study not only demonstrated a noble metal-free photocatalytic system for visible light induced efficient and controllable chemoselective hydrogenation of nitrobenzene to produce aniline, azobenzene and azoxybenzene, but also highlights the great potential of photocatalysis in organic syntheses. (c) 2020 Elsevier Inc. All rights reserved.