Study On Preparation And Performance Of High Activity And High Selectivity Catalyst For Reduction Amination

The effect of calcination temperature on the structure and properties of Al₂O₃ were investigated.According to the analysis results of XRD,SEM-EDS and BET,it is known that the mixed transition stateθ-andδ-Al₂O₃ at a calcination temperature of 950℃are suitable as catalyst supports.Using the transition state Al₂O₃ as the carrier,Ni-Cu bimetallic as the active component and Ca as the promoter,the NiO-CuO-CaO/Al₂O₃ composite oxide catalyst was prepared by impregnation,coprecipitation and microwave grinding method.It was characterized by XRD,SEM-EDS,BET and IR.The results show that the impregnation method is a suitable method for preparing metal composite oxide catalysts compared to the other two methods.Furthermore,the conditions such as the impregnation solvent type,loading mode,impregnation times and solute concentration were optimized for the preparation of catalyst by impregnation method.According to the characterization results,the optimum process was determined.The experimental results show that,the optimum technological conditions are as follows:the optimum technological conditions for dipping solution using anhydrous ethanol,low oxide content and the high order point load,at 60℃direct heating,anhydrous ethanol solution impregnation 2 times,the solute concentration increased by 25%,the prepared catalyst has a specific surface area of 42.01 m²/g,a pore volume of 0.0128 cm³/g,and a pore size of 2.076 nm,the ratio of W_NiO:W_CuO:W_CaOaO in the catalyst is 15:3.5:2.0,which accords with the expected content of each component of the catalyst.In theory,it is more suitable for the synthesis of ethylenediamine by reductive amination of ethanolamine.By employing reductive amination reaction of ethanolamine to synthesize ethylenediamine,the catalytic performances of above catalysts were studied.Reactions were carried out in a fixed bed reactor,ethanolamine,NH₃ and H₂ as the raw materials,under conditions of molar ratio of ethanolamine:ammonia:hydrogen=1:8.04:40,the operation airspeed of ethanolamine is 0.18 h^-1,the reaction temperature is 220℃,a pressure is 1.8 MPa,ethylenediamine was synthesized,and piperazine,polyethylene polyamine compounds also were synthesized.The conversion of ethanolamine was 39.1%,and the selectivity for ethylenediamine 67.9%.