Phenomenological characteristics of cool-flame oxidation of cyclohexane

The phenomenological characteristics of cool flames of cyclohexane are studied. It is shown that cyclohexane flames arise at lower temperatures (beginning at $T\approx230^\circ$C) and lower pressures (lower than 10 torr at $T = 290^\circ$C) than alkane and alkene flames. The temperature dependence of the lower pressure limit of the cool flame is determined. It is established that, depending on the conditions ($p, T$, and $\mathrm{C}_6\mathrm{H}_{12}/\mathrm{O}_2$ ratio), cool-flame ignition is characterized by a rise and drop of the temperature $\Delta T$ or by several peaks imposed on each other. The dependence of the cool-flame structure (for $\Delta T$) on the oxygen content in the reaction mixture is studied. It is shown that the cool flame resulting from cyclohexane oxidation is accompanied by ring opening and formation of products with a smaller number of carbon atoms. It is established that cool flames of cyclohexane are characterized by a negative temperature coefficient.