Building And Investigation Of The Catalytic System For The In-situ Hydrogenation Of Chloronitrobenzene

Realizing catalytic hydrogenation without extra addition of molecular hydrogen using renewable biomass alcohol as hydrogen source is important.H₂ was generated from ethanol aqueous-phase reforming?APR?over Pt/carbon nanotubes?CNTs?and Ni/TiO₂ catalysts in a water/ethanol/m-chloronitrobenzene?m-CNB?reaction system and directly applied into m-CNB hydrogenation.Thus,in-situ liquid-phase hydrogenation of m-CNB was succeeded.As for Pt/CNTs catalysts,the effects of Pt loading method,reduction method and transition metal ion modification were investigated,and the conditions of catalytic reaction were determined.The results show that,comparing with out-tube loading,in-tube loading of Pt catalysts with intratubal confinement effect exhibited significantly higher in-situ m-CNB liquid-phase hydrogenation activity.The best reduction method of catalyst precursor was hydrogen reduction.After the modification of Fe³⁺,Pt-Fe/CNTs catalysts formed,inside CNTs,Pt-Fe alloy and Fe_xO_y species,which both significantly improved catalytic hydrogenation performance of m-CNB and ethanol APR hydrogen producing performance.Thus,the reactivity of in-situ m-CNB liquid-phase hydrogenation was improved.Similarly,Co²⁺and Ni²⁺also showed promoting effect in the reaction.As for Ni/TiO₂ catalysts,the effects of catalyst morphologies?granular,sheet,tubular,spherical?,hydrothermal duration and the modification of Cu²⁺were investigated,and the conditions of catalytic reaction were determined.The results show that,the nanotubular Ni/TiO₂ prepared from one-step hydrothermal method showed higher in-situ m-CNB liquid-phase hydrogenation activity,which attributed to its large surface area,small pore size and uniform distribution,more Lewis acid.With the extension of the hydrothermal duration,the morphology of the catalyst gradually changed from nanotube to nanowire,and the in-situ liquid-phase hydrogenation activity of m-CNB decreased.The activity of Ni-Cu/TiO₂ catalyst prepared by the modification of Cu²⁺can be further improved.