Thermal decomposition of 1,1′-bicyclohexyl, a potential surrogate component of high-density hydrocarbon fuels, was performed in a batch-type reactor to investigate its thermal stability. A first-order kinetic equation is supposed to correlate the decomposition process, and the apparent rate constants, ranging from 0.0223 h^–1 at 683 K to 0.1979 h^–1 at 713 K, are determined. The Arrhenius parameters are determined with the pre-exponential factor A = 6.22 × 10²⁰ h^–1 and the activation energy E_a = 293 kJ·mol^–1. Compared with four typical hydrocarbon compounds, the thermal stability trend is observed in the order of n-dodecane ≈ 1,3,5-triisopropylcyclohexane > bicyclohexyl > n-propylcyclohexane > decalin. Cyclohexane and cyclohexene are found to be the primary products due to the relatively low energy of the C–C bond connecting the two cyclohexyl rings. Bicyclohexyl decomposes into cyclohexane and cyclohexene equivalently at the beginning of the reaction. A probable mechanism on the basis of quantum calculation and GC-MS analyses for the decomposition of bicyclohexyl is proposed to explain the product distribution. It is shown that the formation of decomposition products is mainly obtained through hydrogen transfer, β-scission, isomerization, or dehydrogenation.

中文翻译：

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1,1'-双环己基的热分解动力学及其机理

在间歇式反应器中进行了1,1'-双环己基（一种高密度烃类燃料的潜在替代组分）的热分解，以研究其热稳定性。一阶动力学方程被认为与分解过程相关，并且确定了表观速率常数，范围从683 K的0.0223 h ^–1到713 K的0.1979 h ^–1。Arrhenius参数由指数前因子A = 6.22×10 ²⁰ h ^–1和活化能E _a = 293 kJ·mol ^–1确定。与四种典型的烃类化合物相比，观察到的热稳定性趋势为n-十二烷≈1,3,5-三异丙基环己烷>双环己基>正丙基环己烷>萘烷。由于连接两个环己基环的C–C键的能量较低，因此发现环己烷和环己烯是主要产物。在反应开始时，双环己基等效地分解成环己烷和环己烯。提出了一种基于量子计算和GC-MS分析的双环己基分解的可能机理来解释产物的分布。结果表明，分解产物的形成主要是通过氢转移，β-断裂，异构化或脱氢获得的。