New Technology Of Direct Catalytic Synthesizing Cyclohexylamine From Benzene

Cyclohexylamine is an important raw material of organic chemical and fine chemical intermediate.In this thesis,a green,safe and simple route for the direct synthesis of cyclohexylamine from benzene,hydroxylamine and hydrogen was presented.And a systematic study on the reaction process was carried out.It described that thermodynamic analysis,catalytical design,preparation and characterization,optimization of reaction conditions.Thermodynamic analysis of the direct synthesis of cyclohexylamine was determined.A series of reactions in the reaction system were analyzed.The results show that the above reactions are exothermic reactions in the range of 300-480 K.Synthesis of aniline from benzene and hydroxylamine can not be spontaneous when the temperature is more than 370 K.Low temperature is beneficial to the target reaction.Dynamic operative process for the direct synthesis of cyclohexylamine was investigated.Ru/MCM-41 catalysts for aniline hydrogenation was prepared,and the homogeneous catalyst NH₄VO₃ was selected for synthesis of aniline by amination of benzene.The amination was carried out under the appropriate conditions for the synthesis of aniline by using the dynamic mode of operation.And then,it changed the reaction conditions to adapt to the hydrogenating aniline to synthesize cyclohexylamine.The effects of catalyst carrier,ruthenium loading of catalyst,catalysts dosage on the catalytic performance were investigated.The results showed that MCM-41 was chose as the carrier of ruthenium catalyst,the suitable ruthenium loading was 3%,and the appropriate amount of catalyst was n?NH₄VO₃?:n?Ru?:n?C₆H₆?=0.018:0.004:1.The optimal conditions investigated were HOAc-H₂O?volume ratio?2:1,molar ratio?C₆H₆:NH₂OH?1:2,carried out at 80 ^oC for 2 h,and then heated up to 120 ^oC,hydrogenated to 3 MPa for 2 h.Corresponding yield and selectivity of cyclohexylamine were 20.5%and 62.0%respectively.Reaction process for the direct synthesis of cyclohexylamine was studied.In the new technology,the mode of dynamic operation was improved,amination and hydrogenation were processed at the same time on the basis of dynamic operation research.A new supported bi-functional catalyst Ru-V₂O₅/MCM-41 was successfully developed,and it was used in the direct synthesis of cyclohexylamine from benzene.The carrier and active components loading of catalyst,method of catalyst preparation,catalyst dosage were investigated.The results showed that MCM-41 was chose as carrier of the catalyst,the suitable Ru and V2O5 content was 3%and 10%respectively.And the reaction was conducted at 90 ^oC for 4 h under 5 MPa hydrogen pressure.High cyclohexylamine yield?20%?and cyclohexylamine selectivity?77%?were obtained under the optimized reaction conditions.The stability of catalyst Ru-V2O5/MCM-41 was carried out,and a significant decrease in the activity of catalytic amination reaction and hydrogenation reaction was observed after repeated use of catalyst.the results showed that the main reasons for the deactivation of the catalyst were the loss of the active components and the destruction of the catalyst structure.