Thermal Decomposition of D-cycloserine and Terizidone

Abstract

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.