Efficient Oxidation of Cyclohexane over Bulk Nickel Oxide under Mild Conditions

Abstract

Nickel oxide powder was prepared by simple calcination of nickel nitrate hexahydrate at 500 °C for 5 h and used as a catalyst for the oxidation of cyclohexane to produce the cyclohexanone and cyclohexanol—KA oil. Molecular oxygen (O2), hydrogen peroxide (H2O2), t-butyl hydrogen peroxide (TBHP) and meta-chloroperoxybenzoic acid (m-CPBA) were evaluated as oxidizing agents under different conditions. m-CPBA exhibited higher catalytic activity compared to other oxidants. Using 1.5 equivalent of m-CPBA as an oxygen donor agent for 24 h at 70 °C, in acetonitrile as a solvent, NiO powder showed exceptional catalytic activity for the oxidation of cyclohexane to produce KA oil. Compared to different catalytic systems reported in the literature, for the first time, about 85% of cyclohexane was converted to products, with 99% KA oil selectivity, including around 87% and 13% selectivity toward cyclohexanone and cyclohexanol, respectively. The reusability of NiO catalyst was also investigated. During four successive cycles, the conversion of cyclohexane and the selectivity toward cyclohexanone were decreased progressively to 63% and 60%, respectively, while the selectivity toward cyclohexanol was increased gradually to 40%.

Monodispersed NiO Nanoparticles into SBA-15: An Efficient Nanocatalyst to Produce Ketone-Alcohol (KA) Oil by the Oxidation of Cyclohexane in Mild Conditions

“…In order to find the optimal conditions for the oxidation reaction of CXN over SBA-15 supported NiO NPs nanocatalyst (NiOi@SBA-15), and for comparison purposes, unsupported bulk NiO (prepared by calcination of nickel nitrate 5 h at 500 °C) was used as a catalyst for the optimization study. The obtained results were reported recently by Abboud et al [48]. The highest conversion of cyclohexane and highest selectivity toward KA…”

“…It should also be noted that the CXK and CXA selectivity was also slightly affected. The selectivity of CXK decreased from 73% to 68%, while the selec- In this study, NiO Ac @SBA-15 exhibited high stability after four successive runs compared to 5 mg (Figure S6) and 50 mg [48] of bulk NiO. After four cycles, the CXN slightly decreased from 99% to 88%.…”

“…The obtained results are plotted in Figure 10. In this study, NiOAc@SBA-15 exhibited high stability after four successive runs compared to 5 mg (Figure S6) and 50 mg [48] of bulk NiO. After four cycles, the CXN slightly decreased from 99% to 88%.…”

“…The obtained results are presented in Figure 9. Compared to results obtained with similar amounts of bulk NiO (i.e., 5 and 15 mg of bulk NiO) [48], the conversion of CXN over SBA-15-supported NiO NPs was much higher than that obtained with bulk NiO. A total of 99%, 85%, 75%, and 90% of CXN was converted to KA oil using NiO Ac @SBA-15 (Ni: 7.26%), NiO Nt @SBA-15 (Ni: 3.66%), NiO Cl @SBA-15 (Ni: 4.03%), and NiO Sl @SBA-15 (Ni: 5.55%) respectively, compared to 17% and 21% over 5 mg and 15 mg of bulk NiO, respectively.…”

“…The oxidation of cyclohexane over bulk NiO using H 2 O 2 was performed according to a method described previously by Abboud et al [48]. 2 mL (18.5 mmol) of CXN and 4.2 mL (18.5 mmol) of dodecane (internal reference) and 10 mL of acetic acid were added to a mixture of 50 mg of NiO dispersed in 10 mL of acetic acid.…”