Reaction mechanism of cumene hydroperoxide decomposition in cumene and evaluation of its reactivity hazards
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Cumene hydroperoxide (CHP), a type of organic peroxide, is widely used in the chemical industry for diverse applications. However, it decomposes and undergoes highly exothermic runaway reactions under high temperature because of its unstable peroxide functional group. The risk of runaway reaction is intensified by the fact that operation temperature of CHP is close to its onset temperature in many cases. To ensure safe handling of CHP in the chemical industry, a lot of research has been done on it including theoretical research at the microscopic level and experimental research at the macroscopic level. However, the unstable radicals in the CHP decomposition reactions make it difficult to study its reaction pathway, and therefore lead to incomplete understanding of the reaction mechanism. The slow progress in theoretical research hinders the application of the theoretical prediction in experimental research. For experimental research, the lack of integration of operational parameters into the reactivity evaluation limits its application in industrial process. In this thesis, a systematic methodology is proposed to evaluate the reactivity hazards of CHP. This methodology is a combination of theoretical research using computational quantum chemistry method and experimental research using RSSTTM. The theoretical research determined the dominant reaction pathway of CHP decomposition reaction through the study of thermodynamic and kinetic stability, which was applied to the analysis of experimental results. The experimental research investigated the effect of CHP concentration on runaway reactions by analyzing the important parameters including temperature, pressure, self-heat rate and pressure rate. This methodology could also be applied to other organic peroxides or other reactive chemicals. The results of theoretical research on reaction mechanism show that there is a dominant reaction pathway, which consumes most of the CHP in decomposition reaction. This conclusion agrees with the experimental results that 40 wt% is a critical point for almost all important parameters of runaway reactions. In the high concentration range above 40 wt%, some unknown reaction pathways are involved in decomposition of CHP because of lack of cumene. The shift of reaction mechanism causes the change of the effect of concentration on runaway reactions.