Thermal and FTIR spectral studies of N,N′-diphenylguanidine

Thermal decomposition of N,N ′-diphenylguanidine (DPG) was investigated by simultaneous TG/DSC-FTIR techniques under nonisothermal conditions. Online FTIR measurements illustrate that aniline is a major product of DPG decomposition. The observation that the activation energy depends on the extent of conversion indicates that the DPG decomposition kinetics features multiple processes. The initial elimination of aniline from DPG involves two pathways because of the isomerization of DPG. Mass spectrometry and thin film chromatography suggest that there are two major intermediate products with the major one of C 21 N 3 H 17 . The most probable kinetic model deduced through multivariate nonlinear regression method agrees well with the experimental data with a correlation coefficient of 0.9998. The temperature-independent function of conversion f ( α ), activation energy E and the pre-exponential factor A of DPG decomposition was also established through model-fitting method in this research.