Effects of Oxygen: Experimental and VTST/DFT Studies on Cumene Autoxidation with Air under Atmospheric Pressure

[Image: see text] The mechanism of how oxygen affects cumene autoxidation related to temperature is still bewildering. Kinetic analysis of cumene autoxidation with air at a pressure of 1.0 atm was investigated by experiments and variational transition state theory/DFT. Oxygen was the limiting factor for cumene autoxidation above 100 °C, although it had negligible impacts on cumene autoxidation at 70–100 °C. The kinetic analysis by VTST coupled with DFT calculations proved that {k(6,reverse)[ROO(•)]}/{k(7,forward)[RH](0) [ROO(•)]} > 10(3) (70–120 °C), suggesting that ROO(•) tended to decompose back to R(•) and O(2) rapidly, whereas it was much slower for ROO(•) abstracting a hydrogen atom from RH to form ROOH. When the concentration of oxygen was higher than the critical value ([O(2)](critical)), it could not significantly affect the equilibrium concentration of ROO(•), which in turn could not affect the autoxidation rate significantly. Besides, the critical oxygen concentration ([O(2)](critical)) was exponentially related to 1/T, which was consistent with Hattori’s experimental results.