Acid-treated Activated Carbons Catalyzed Reduction Of Nitrobenzene By Hydrazine Hydrate

Activated carbon （AC） was usually used as a substrate for loading active catalyticcenters due to its high surface area, tunable porosity, and high stability in caustic andacidic conditions. Both the texture and surface chemistry of AC support have distincteffect on the catalytic performance of AC supported catalyst. However, activated carbonitself can be used as catalyst for chemical reactions. Here, we employed an activatedcarbon as a metal-free catalyst for the reduction of nitrobenzene and oxidation ofbenzene. The activity of catalysts was studied. Following are the results:1The effect of different inorganic acids （HCl、H2SO4、HNO3） treatment on thereduction of nitrobenzene was investigated. The H-AC sample （activated carbon treatedby HCl） shows the highest catalytic activity. The samples are characterized by evolvingby X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FTIR）, N₂adsorption and Boehm titration. The results show that acid treatment introduced surfacefunctional groups on activated carbon, which is conductive to reduction of nitrobenzene.We obtained100%nitrobenzene conversion and100%aniline selectivity under theconditions: using H-AC sample as catalyst,0.3g catalyst, nitrobenzene4.89mmol,absolute alcohol5ml, n（hydrazine hydrate）:n（nitrobenzene）=2.5,80℃for2h.2The effect of different inorganic acids （HCl、H2SO4、HNO3） treatment on theone-step catalytic oxidation of benzene to phenol was also studied. The N-AC sample（activated carbon treated by nitric acid） shows the highest catalytic activity. Reactioncondition as reaction time, reaction temperature and the volume of solvent was studied.We obtained34.23%benzene conversion and92.39%phenol selectivity under theconditions: using N-AC sample as catalyst,0.3g catalyst, benzene5.6mmol, solventCH3CN5ml, n（H2O2）:n（benzene）=3:1,60℃for6h.