Study On The Preparation And Hydrogenation Of Nitrocyclohexane

Cyclohexanone oxime is an important fine chemical intermediate and widely used in producing caprolactam. Currently, the major industrial technique to cyclohexanone oxime is the cyclohexanone-hydroxylamine process. Considering the cyclohexane has no double bond , lone-pair electron and polarity , furthermore, the bond energy of its covalent bond is high, it is impossible to have it oxidized under moderate condition. Whereas, the selectivity is bad. Therefore , the single coversion of cyclohexane is usually controlled under 5% for traditional manufacturing technique and the yeild of cyclohexanone is bad. So it has realizable and theoretical meaning to searching for an industrial route to produce cyclohexanone oxime.In the fist part of this thesis, the nitrocyclohexane was prepared by nitration of cyclohexane in the presence of N-hydroxyphthalimide as a catalyst. The effects of reaction temperature, reaction time, amount of catalyst and molar ratio of raw materials on yields were investigated. The results showed that the proposed method has many advantages such as the mild reaction condition, the lower reaction temperature etc. The productions maianly include nitrocyclohexane, cyclohexanone, cyclohexanol and 1-nitrocyclohexene. The yield of the nitrocyclohexane per pass was up to 13.7%.In the second part, P-Mo-V heteropoly acids were synthesized by multi-step method and characterized by IR. The IR spectrum indicated that the compounds prepared in present work had Keggin structure. The catalytic performance of the heteropoly acids obtained for the direct nitration of cyclohexane to nitrocyclohexane was also investigated. Based on the result, the heteropolyacid showed its certain catalytic activity and the selectivity of nitrocyclohexane was up to 92% as a potential catalyst.Then, the effects of reaction temperature, different solvent (ethylene diamine, aqueous solution of sodium hydroxide, cyclohexyl amine), amount of catalyst, reactant concentration and reaction time on hydrogenation of nitrocyclohexane catalyzed by Pd/C were studied. It is proved that the react solution, reactant concentration and amount of catalyst effected obviously the selectivity of cyclohexanone oxime while the influence of other factors can be ignored. The conversion of nitrocyclohexane reached nearly 100% and selectivity of cyclohexanone oxime was up to 70% when the ethylene diamine is used as a react solution of hydrogenation on nitrocyclohexane catalyzed by Pd/C.Finally, Ni/CNFs was prepared with precursors nickel acetate and nickel nitrate by loading the activated components nickel on the pure CNFs through wet impregnation method. The catalytic performance of the prepared Ni/CNFs obtained for hydrogenation of nitrocyclohexane was also studied in this thesis. Based on the result, the catalitic activity of nickel acetate-drived was proved and the yeild of cyclohexanone oxime was up to 19.19% when the conversion of nitrocyclohexane reached 99.70%.In conclusion, the nitration of cyclohexane in the presence of catalysis and catalytic hydrogenation of nitrocyclohexane have been investigated and the method of synthesizing cyclohexane through nitrocyclohexane proposed in this thesis affords some basic studies for improving the related production technology.