Study On Synthesis Of Ethylenediamine By Catalytic Alkylation Of Ammonia

Ethylenediamine and its derivatives are important chemical raw materials and fine chemical intermediates,widely used in epoxy resin curing agent,dye intermediates,electroplating solution,surfactant,lubricant additives,paper wet strength agent,organic solvents and chemical analysis reagents,etc.It can be used in the production of low molecular weight polyamide resin,chelating agent,insect repellent,soil improvement agent and lubricant,involving food,medicine,pesticide,automobile,shipbuilding,civil construction,water treatment,papermaking,rubber,textile and electronics industries.The synthetic methods of Ethylenediamine included the follows:EDC method,Ethanol,Ethylene oxide,Ethylene ammoniation method and diethylene glycol ammoniation method and so on.The method of EDC is the major industrial method.But the EDC method has some disadvantages such as poor quality,serious corrosion of equipment and waste emissions.It is not adapt to the current concept of green environmental protection and energy saving,and it is necessary to explore a new process for the preparation of Ethylenediamine.From the view of reaction machanism,the ammonia alkylation of ethylene glycol is the best route for the preparation of Ethylenediamine.It has been reported that some metal catalysts exhibit catalytic activity for the catalytic amination of bifunctional alcohols.In order to seek the environmentally friendly green synthesis process,the ammonia alkylation reaction with ethylene glycol as raw material were studied in this work.The main research contents and conclusions are as follows:Screening of catalysts and activity evaluation.Five kinds of catalysts,NiO/Al₂O₃,CuO/Al₂O₃,CoO/Al₂O₃ CoO/CuO/Al₂O₃,NiO/CuO/Al₂O₃ were synthesized and characterizied by XPS,XRD,SEM,BET,TGA,etc.The activity evaluation were carried out through the ammonia alkylation reaction of ethylene glycol.The results showed that the NiO/Al₂O₃ catalysts had better catalytic activity with conversion rate of 52.2%of ethylene glycol and selectivity of ethylenediamine 42.7%in the present of by-products,such as the depth alkylation of ammonia.The CuO/Al₂O₃ catalysts also showed essential catalytic activity with conversion rate of 38.3%of ethylene glycol and the selectivity of ethylenediamine 20.4%.It found that catalytic activity was obviously improved with conversion rate of 68.6%of ethylene glycol and selectivity of 56.7%of ethylenediamine in the present of NiO/CuO/Al₂O₃ catalysts.The experimental results showed that there may be synergies between NiO and CuO in the two-components catalyst systems NiO/CuO/Al₂O₃,this synergies may be improved the catalytic performance.Doping modification of catalyst.The CoO/CuO/Al₂O₃ catalysts showed better catalytic activity with conversion rate of 61.3%of ethylene glycol and selectivity of ethylenediamine 51.2%.This results suggests that CoO components had better catalytic synergy to ammonia alkylation reaction of ethylene glycol.The ternary active component catalyst NiO/CuO/CoO/Al₂O₃ was prepared by equal volume impregnation method.The mole ratio is 3:1:1:10、3:1:2:10、3:1:3:10 and characterized by XRD,SEM,BET,TGA,etc and applied to the synthsis of ethylenediamine.Compared with the two component supported catalyst NiO/CuO/Al₂O_3,the catalytic activity had not significant increase.This part of the work needs to be deepened.The optimization of synthetic conditions.Ethylenediamine was prepared with ethylene glycol and liquid ammonia as raw materials in the present of supported bicomponent composite metal oxides NiO/CuO/Al₂O₃ catalyst.The reaction mixture was analyzed by GC.The effects of different catalyst composition,material ratio,temperature and reaction time on the reaction were investigated.The the conversion rate of ethylene glycol could reach 68.6%with the selectivity of 56.7%of ethylene diamine under the conditionofmoleratioNi:Cu=3:1,additionamountofcatalysts3%,NH₃/HOCH₂CH₂OH mass ratio 4:1,temperature 180℃,pressure 0.6 MPa and reaction time 4 h.Compared with the traditional dichloroethane method,this process is more clean and environmental friendly.