Fig. 6.
Effect of reaction time on cyclohexane conversion, selectivities for the main product, intermediate product, and by-products. Reaction conditions: cyclohexane 100 mL, VAlPO4 berlinite catalyst 5 mg, acetic acid solvent 40 mL, O2 pressure 0.1 MPa, reaction time: 4 h. (White circle) cyclohexane conversion; (Black circle), (Black square), (Black up-pointing triangle) and (Black down-pointing triangle) selectivity for KA oil, CHHP, acids and esters, respectively. KA oil: cyclohexanol and cyclohexanone; CHHP: cyclohexyl hydroperoxide; acids: C4–C6 diacids; esters: synthesized by the reaction of C4–C6 diacids and cyclohexanol