The synthesis of diphenyl toluene dicarbamate from urea

toluene diamine and phenol is a complex reaction system. On the basis of the analysis for similar reaction system

four possible reaction pathways for synthesizing diphenyl toluene dicarbamate via urea route were proposed. The fundamental thermodynamic data of components in this reaction system were calculated by several methods of group contribution. The reaction enthalpy

Gibbs free energy change and equilibrium constant of all the reactions of the four possible reaction pathways were obtained. According to the results of thermodynamic calculation and experimental data in literature

the feasibility and difficulty of each reaction pathway were discussed. The results show that a better reaction pathway is urea reaction with phenol to give phenyl carbamate and then phenyl carbamate interacting with toluene diamine to form diphenyl toluene dicarbamate. The results from thermodynamic calculation and analysis can provide a theoretical basis for the experimental study and process development of the reaction.