Study On Synthesis Of Isophoronediamine

Isophoronediamine(IPDA) is an important compound of amines,it is mainly utilized as hardners for epoxy resins, crosslinking agent and couplant for polyurethane, and amine component for polyamide, having a promising application prospect. Normally, isophoronediamine is synthesized by isophoronenitrile(IPN), ammonia, and hydrogen in the presence of catalyst. Nowadays, more and more importance is attached to the two-step synthesis path in which isophoronenitrile is firstly iminated, followed by catalytic hydrogenation. In this paper, the process for synthesizing IPDA with isophoronenitrile as raw material is studied.Imination was investigated in the solvent of methanol with IPN and ammonia as raw materials under303.15-333.15K, with different ammonia/IPN mole ratios. Gas chromatography is employed to trace the concentration of substrate, and the structure of products is identified by GC-MS method. Kinetic model of imination is derived based on reaction mechanism, and the kinetic eqation of imination is gained by data fitting. The results show that the imination of IPN is apparently second-order exothermal reaction, and the reaction△H was-16.21kJ/mol,the apparent activation energy of the forward reaction and backward reaction Ea, Eb was23.08kJ/mol and39.29kJ/mol, and the pre-exponential factor of forward and backward reaction kao, kbo was9.191×103L/(mol·s) and3.478×106L/(mol·s) respectively. The kinetic equation was verified, and the experiment result was in good agreement with the prediction. All these will benefit for improving the yield of isophoroneimine(IPIN) and provide responding guidance on its industrialization.The hydrogenation of IPIN was studied in autoclave. GC-MS method is employed to analyze the products of hydrogenation, and the structure of principal product and by-product is identified, and the network of hydrogenation is established. The activity, selectivity, and the effect on the yield of IPDA of Raney Ni, Raney Co and Co/diatomaceous earth is mainly investigated in autoclave.Raney Co is used to study the effect of the quantity of catalyst, reaction time, reaction temperature and pressure, and quantity of NaOH on hydrogenation. The optimal results are as follows: the reaction temperature is100℃, the hydrogenation pressure is10Mpa, the mole raio of amomia/IPN is20, the weight ratio of catalys/IPNt is93%, the reaction time is30minutes, and the yield of IPDA is76%. The crude product of hydrogenation is refined by vacuum distillation and a purification of98%of IPDA is obtained, which is characterized by1H-NMR and IR.