Pyrolysis kinetics and mechanism of ethylcyclohexane

Ethylcyclohexane is a representative component of endothermic hydrocarbon fuel. The present work involved a comprehensive investigation of the pyrolysis process of ethylcyclohexane at different temperatures and times as well as its kinetics. At the test temperature T ranges from 683 to 723 K, the pyrolysis process of ethylcyclohexane conformed to the first-order kinetics. The apparent rate constants at different test temperatures were obtained, along with the corresponding Arrhenius parameters of pre-exponential factor A = 1.14 x 10(15)s(-1) and apparent activation energy E-a = 270 kJ/mol. The kinetics parameters for the pyrolysis of ethylcyclohexane were compared with those of several typical hydrocarbon compounds, and the results showed that thermal stabilities at given temperatures were arranged with the following order: 1,3,5-triisopropylcyclohexane < bicyclohexyl < n-propylcyclohexane < ethylcyclohexane approximate to decalin. The total heat sink of ethylcyclohexane, including the physical and chemical heat sink, was then calculated. Thermal decomposition led to an increase of heat sink by approximately 17 percent. Furthermore, based on the result of product distribution and quantum calculation result, we proposed a mechanism to clarify the pyrolysis process of ethylcyclohexane.