The formation mechanism and thermal decomposition kinetics of 2,4,6-trinitroresorcinol in the dinitrobenzene production

2,4,6-Trinitroresorcinol (TNR), one main by-product in the dinitrobenzene (DNB) production process, is self-reactive substance and has led to tragic explosion incidents in China. In this article, the formation mechanism of TNR during the DNB production process was studied employing HPLC and HPLC-MS technique. Thermal decomposition behavior of TNR was also systematically studied by differential scanning calorimeter (DSC). The decomposition kinetics of TNR were investigated employing both iso-conversional (Friedman and Ozawa method) and model-fitting method. The formation mechanism of TNR during the dinitrobenzene (DNB) production is confirmed: The two by-products of dinitrophenol (DNP) and trinitrophenol (TNP) produced in the benzene mononitration stage are further nitrated to form tetranitrophenol (TTNP) in the mononitrobenzene (MNB) nitration stage. Then most of TTNP will be hydrolyzed to form the TNR during the water washing process. The decomposition process of TNR has been proven to follow three consecutive steps (A→B1→B2→B). The former two steps present autocatalytic behavior while the last step obeys N-order reaction model. The accuracy of the developed decomposition model and the obtained model parameters have been demonstrated by the comparison of the simulated and experimental DSC data and the activation energy obtained by both the iso-conversional method and model-fitting method. The same trend of experimental and simulated results about isothermal reaction further verify the building model.