Synthesis of 4

4-methylenedianiline(MDA)from aniline and formaldehyde is a complex reaction system.The fundamental thermodynamic data of substances in the reaction system were calculated with various group contribution methods.The reaction enthalpy，Gibbs free energy change and equilibrium constant of the main reactions were calculated.The influence of reaction temperature and raw material ratio of aniline to formaldehyde on the reaction equilibrium was investigated by thermodynamic simulation and validated by comparison with experimental data.It is shown that higher reaction temperature restrains the formation of byproducts，so higher yield of MDA can be obtained.The optimized molar ratio of aniline to formaldehyde is 3∶1.Under this reaction condition，by-products are less and subsequence separation of aniline is easier.The comparison with experimental data shows that the calculation results are reasonable.