Study on thermal stability and thermal decomposition mechanism of 1,1-di-tert-butyl peroxy-3,3,5-trimethyl cyclohexane through adiabatic calorimeter and theoretical approach

Abstract

Organic peroxides (OPs) readily demonstrate oxidising and self-reactive characteristics that can easily cause fire and explosion. Information regarding the thermal stability and other properties of OPs should be provided to industries that use these materials to avoid unexpected thermal decomposition in the workplace. The target substance in this study, 1,1-di-tert-butyl peroxy-3,3,5-trimethyl cyclohexane (TMCH), is commonly used in the chemical industry, and scholars have considered its applications in the aerospace sector in the last two decades. Because of different conditions in the chemical and aerospace industry, parameters measured under the previous conditions leave unforeseen thermal risks. The thermal behaviour and runaway pathway of TMCH, especially under adiabatic conditions, were investigated using experimental and theoretical computation methodologies. Differential scanning calorimetry, thermogravimetric analyser, and adiabatic accelerating calorimeter were applied for the thermokinetic constants of TMCH. Experimental results indicated that TMCH could release heat and gas when decomposed, with a high potential explosion hazard. Molecular simulation calculations can compensate for the measurement restrictions of instruments. The peroxy bond dissociation energy of TMCH was amended by basis set superposition error correction calculations. The analysis determined the thermal runaway reaction pathway of TMCH and evaluated the formation mechanism of the transition state defined by the intrinsic reaction coordinate. The main reason for TMCH mass loss caused by heating was the release of CO2 and ethane gas. This paper confirmed experimental results by molecular simulation with thermodynamic constants. The study results can be used as a reference for the loss prevention and control of TMCH in more potential engineering applications.