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The article considers two intermediate products of positive photoresists (1,2-naphthoquinonediazide-(2)-5-sulfonic acid of monosodium salt — Dye M and 1,2-naphthoquinonediazide-(2)-5-sulfochloride — Dye N2) from the standpoint of the tendency to explosive transformation. The experimental values of flash points determined on the OTP setup were 130 °C for Dye M and 95 °C for Dye N2. These values are close to the temperatures of the beginning of intensive exothermic decomposition (132 and 111 °C, respectively) obtained by thermogravimetric analysis. In addition, this analysis showed the presence of exothermic peaks in the studied samples both in the air and in an inert atmosphere of helium, which is a necessary condition for the manifestation of a tendency to explosive transformation. To confirm the possibility of explosive transformation, the flash points of substances were also determined by the calculation method according to the formula, which is a consequence of the problem of thermal explosion during convective heat exchange with the environment, and gave a result close to the experimental one (the values were 138 and 105 °C, respectively). For this calculation the following was used: the kinetic parameters determined by the Kissinger method, the values of the density of substances determined on an automatic pycnometer, as well as the values of the heat of explosive transformation obtained with the help of the Real computer thermodynamic program. The research results confirming the tendency of the investigated compounds to explosive transformation, as well as the critical temperatures, exceeding which is unacceptable, were transferred to the production of FGUP GNTs NIOPIK to create a safe technological process, safe storage and transportation conditions. Considering the accuracy of the measuring devices, the process temperature should not exceed 125 °C for Dye M and 90 °C for Dye N2. The conducted studies and calculations show that the computational and experimental approaches have good convergence, give values in a close temperature range, and increase the reliability of the obtained results.

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Thermal decomposition of D-cycloserine and terizidone in the air and in the inert helium and nitrogen media was studied using differential thermal analysis. It is shown that upon reaching 145 °C and 135 °C respectively, the intense exothermic decomposition begins. In the inert environment the substances retain ability to intensively exothermic decomposition, which is a required condition for the possibility of explosive transformation occurrence. To confirm the possibility of explosive transformation, the flash points of substances were calculated according to the formula, which is a consequence of the problem of thermal explosion during convective heat exchange with the environment. The obtained result is close to the experimental one (temperatures 102 and 104 °C, respectively). The calculations used the kinetic parameters determined by the Kissinger method and corresponding to the values obtained by the Ozawa — Flynn — Wall method. Densities of the substances found using an automatic pycnometer, and the heat of explosive transformation obtained experimentally and with the use of the computer thermodynamic program Real are also considered. It is concluded that both substances are prone to intense exothermic decomposition, and, under certain conditions, the development of a thermal explosion is possible. Recommendations on ensuring industrial safety when working with D-cycloserine and terizidone are sent to FGUP «GNTs «NIOPIK». Particular attention should be paid to temperature control at all the stages of the production process. Based on the results obtained in the study, it should not exceed 110 °C for D-cycloserine, and 120 °C for terizidone considering the error of measuring instruments.

The article studies the mechanism of thermal decomposition of two drugs from the group of isoxazolidines D-cycloserine, and terizidone, potentially exposed to the action of elevated temperatures in production (preparation and drying stages). As a result of series of the analytical experiments on the study of solid products of samples thermal decomposition by IR spectroscopy, including with the participation of a comparative sample (more thermally stable nootropic drug fonturacetam), it was established that the antibiotics D-cycloserine and terizidone containing in their molecular formula a five-membered heterocycle with the [–C–O–N–] group (absorption band in the area of 1461 cm–1) have low thermal stability associated with the ease of breaking N–O bond. It is noted that at the maximum degrees of decay, the specified absorption band weakened until it completely disappeared. The obtained results on thermal decomposition, apparently, can be interpolated to all the substances having specified heterocycle in the structure, which is explosiphoric. Before launching into production, when modeling substances with the specified pharmacological properties, it is required, if possible, to avoid structures with a similar heterocycle with a choice of more heat-resistant analogues that are not inferior in efficiency. Such solutions to reduce fire hazard at the stage of development of technological processes seem to be the most efficient. The study results confirming the propensity of the studied compounds to thermal decomposition at relatively low temperatures contributed to the creation of a safe technological process, storage and transportation conditions at the place of production of FGUP «GNTs «NIOPIK».