Facile preparation of highly-dispersed cobalt-silicon mixed oxide nanosphere and its catalytic application in cyclohexane selective oxidation

Table 1 Catalytic oxidation of cyclohexane over the catalysts

Catalysts	Conversion (mol%)	K-A oil (mol%)	Products distribution (mol%)^a
			A	K	CHHP	Acid	Ester
Co-SiO₂	6.0	85.7	45.7	40.0	0.3	10.3	3.7
C-Co₃O₄	3.8	78.4	50.4	28.0	9.3	10.8	1.5
Co(OAc)₂ ^b	3.3	78.2	43.2	35.0	4.3	15.0	2.5
Co-HMS ^b	4.8	76.9	39.6	37.3	0.4	15.6	7.1

Reaction was carried out with 0.12 g of catalyst and 0.12 g of TBHP in 15 g of cyclohexane at 388 K for 6 h under 1.0 MPa O₂.^a A, cyclohexanol; K, cyclohexanone; CHHP, cyclohexylhydroperoxide; Acid, mainly adipic acid; Ester, mainly dicyclohexyl adipate; K-A oil, A and K.^b Results from Chen et al. [19] under the same reaction conditions.