The kinetic behavior of the liquid-phase oxidation of cyclohexane was investigated in a bubble column under 1.1 MPa at various temperatures

in which gases with O2 concentrations ranging from 5% to 99% were used as oxidants.By comparing the non-catalytic and catalytic oxidation of cyclohexane

the free radical mechanism of the oxidation was discussed in detail.Both the mechanism analysis and experimental data showed that the catalyzed liquid-phase oxidation of cyclohexane was a reaction of first-order with respect to both cyclohexane and oxygen.For the non-catalytic oxidation

an induction period was obvious.During the non-catalytic oxidation of cyclohexane by oxygen

the chain initiating reaction was the rate determining step.Beyond the induction period

the reaction was accelerated and exhibited auto-catalytic behavior due to the release of radicals through the decomposition of cyclohexyl hydroperoxide when its concentration accumulated to a certain degree.On the other hand

in catalytic oxidation the cyclohexyl hydroperoxide decomposed rather quickly

and then accelerated the reaction.And during the reaction

the concentration of cyclohexyl hydroperoxide kept very low and the chain propagation became the rate limiting step.