Thermal Risk Analysis Based on Reaction Mechanism: Application to the 2,6-Diaminopyrazine-1-oxide Synthesis Process

Abstract

Thermal risk analysis is essential for the development of chemical reactions. This work should be carried out on the basis of a thorough comprehension of the reaction mechanism. In this article, the synthesis process for 2,6-diaminopyrazine-1-oxide (DAPO), an important intermediate in the synthesis of the famous explosive 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105), was employed to show the importance of understanding the reaction mechanism for thermal risk analysis. First, we investigated the reaction mechanism of DAPO synthesis. The reaction mechanism was divided into two stages on the basis of the amount of triethylamine dosed: the first half of triethylamine dosing and the second half of triethylamine dosing until the end of the reaction. Then the thermal properties of DAPO synthesis and the thermal stability of the materials involved were experimentally studied using a reaction calorimeter (RC1) and a differential scanning calorimeter (DSC), respectively. The results show that the temperature corresponding to the maximum reaction rate reached in a time of 24 h under adiabatic conditions (T D24) is higher than the maximum temperature of the synthesis reaction (MTSR) for both of these stages, indicating that once cooling failure occurs, immediately stopping addition of triethylamine could prevent the occurrence of secondary decomposition.

Optimization and Thermal Risk Analysis of 3,4-bis(4-Aminofurazano-3-yl) Furoxan Synthesis Process Based on Reaction Mechanism

“…Throughout the reaction testing process, RC1e accurately detects temperature changes, converts them into heat flow signals, and presents them for display. Integration of these heat flow signals allows for the determination of the total heat release during the reaction …”

“…Integration of these heat flow signals allows for the determination of the total heat release during the reaction. 11 2.3.2. Accelerating Rate Calorimeter.…”

Evaluation of the Thermal Hazard of the Oxidation Reaction in the Synthesis of 3,4-Bis(4-nitrofurazan-3-yl)furoxan

“…On the basis of the above descriptions, there are many invisible dangers in the oxidation reaction during the synthesis of DNTF, not only in the reaction step but also in the preparation of the reaction solution and in the postprocessing stage, which researchers usually ignore. − …”

Thermal and Kinetic Research on a Highly Exothermic Condensation Reaction by Powerful Calorimeters

“…In the fine chemical and pharmaceutical industries, the operations of highly exothermic reactions are ubiquitous, leading to serious safety issues or even catastrophic industrial accidents, which has been a widespread concern. − The safe operating conditions generally constitute the first line of defense to prevent uncontrollable incidents in the reactors, especially when involving the fast exothermic reactions or thermally unstable compounds. − Hence at present, from the safety viewpoint the studies and evaluations of exothermic properties are policy-required for almost all the exothermic process development. At the stage of assessing potential runaway events or failure scenarios, thermal and kinetic data of a reaction are necessary for prediction of hazardous situations.…”

“…3 and C tri are the initial concentrations of POCl 3 and triethylamine, respectively, and d, e, and f are the reaction orders of phenol (1), POCl 3 , and triethylamine, respectively. Because of the huge difficulty in detecting or separating the components at the transition state, this treatment method is beneficial to propose a convenient and practical kinetics model.…”