One-Step Synthesis Of Novel Carbon-Based Solid Acid Catalysts By Hydrothermal Carbonization And Their Performance In Synthesis Of Nitrobenzene To P-Aminophenol

P-Aminophenol (PAP) is widely used in the medical industry. So far as we know, the hydrogenation and Bamberger rearrangement of nitrobenzene (NB) to PAP is very competitive. However, this reaction was carried out in acid medium such as sulfuric acid solution in industry, which suffered from environmental pollution and equipment corrosion. Thus, this paper made some attempts to substitute sulfuric acid by novel carbon-based solid acids. Besides, several carbon-based solid acid supported Pt bi-functional catalysts were prepared and used for the hydrogenation of NB to PAP.In this thesis, a series of novel carbon-based strong acid catalysts was prepared by one-step hydrothermal carbonization for the first time. The catalytic performances of the catalysts for the hydrogenation and Bamberger rearrangement of nitrobenzene to p-aminophenol were investigated with Pt/C. The effects of the conditions of hydrothermal carbonization such as the carbohydrate type, the hydrothermal temperature, the hydrothermal time, the acid type and the acid concentration on the performance of the carbon-based solid acid were investigated. The samples were characterized by FT-IR, SEM, XRD and acid base titration. The results indicated that the best hydrothermal carbonization condition was as follows:the mixture of10g Starch,10mL H2SO4(98%) and50mL distilled water were placed in100mL Teflon-lined stainless steel autoclave, which were heated in an oven at180℃for4h. The as-prepared carbon-based solid acid showed higher selectivity to PAP than the general ZSM-5and solid superacid on the same reaction conditions.Using the best carbon-based solid acid as acid catalyst and Pt/C as hydrogenation catalyst, the reaction condition of the hydrogenation of NB to PAP was optimized. The results showed that the optimal reaction conditions as follows:reaction temperature85℃, reaction pressure0.4MPa,0.0035g3%Pt/C (70%of water),0.01g CTAB,1.0g10S-Starch,0.5g NB,50mL distilled water, under which the PAP selectivity reached75.5%with60.8%of NB conversed after10h.On the basis of the study mentioned above, a series of carbon-based solid acid supported Pt bi-functional catalysts was prepared. Their catalytic performances for the hydrogenation of NB to PAP were investigated. The results showed that the bifunctional catalysts showed some activity and selectivity to p-aminophenol. Using2%Pt/Starch and10S-Starch as catalyst, the conversion of the NB was93.6%and the selectivity to PAP was23.4%at85℃and0.4MPa hydrogen pressure for10h.