Liquid–crystal equilibrium application for 2,3-DNT initial thermal decomposition analysis

Abstract

2,3-Dinitrotoluene (2,3-DNT) thermal decomposition and its products were studied. Main attention was paid on the initial stage of decomposition, because the degradation of even a few percent of high energetic compound may cause significant hazard. Partial decomposition of 2,3-DNT was performed conditioning at the temperature range of 457–568 K. Impurities production at the initial stage of decomposition was determined by the analysis of melting enthalpy decrease with cryometric method. Mean self-aggregation number of the initial substance was defined and determined to estimate the molecular mass of products of 2,3-DNT thermal conditioning. MALDI TOF method was used for independent molecular mass verification. 2,3-DNT is thermally stable substance. Heating of its sample from the ambient temperature to 486 K with the heating rate of 2 K min−1 does not cause thermal decomposition. Very good reproducibility of melting process performed on the same sample was obtained. Only prolonged conditioning at raised temperature leads to initial substance loss. Two competitive reactions, aggregation and decomposition, were run during 2,3-DNT thermal conditioning. Heating with low heating rate leads to products with higher molecular masses. Two different results prove that: MALDI TOF analysis and the melting enthalpy decrease which is higher than the increase in impurities content determined with cryometric method. Mass spectrum of the thermally conditioned 2,3-DNT samples includes strong signals with (among others) following m/z values: 551, 687, 1062, 1137, 1211. Formed macromolecular compounds were stable until the temperature of 500 K.