Mechanism of direct oxidation of cyclohexene to cyclohexanone with nitrous oxide. Theoretical analysis by DFT method

Abstract

New very effective results on the liquid-phase oxidation of cyclohexene to cyclohexanone by nitrous oxide are analyzed using the B3LYP/6-31G* approximation to predict a two-step reaction mechanism correlated with the experimental data.

Nitrous oxide in oxidation chemistry and catalysis: application and production

“…The oxygen transfer is assumed to occur via the 1,3-dipolar cycloaddition mechanism. This mechanism has been convincingly substantiated by both experimental [89][90][91][92][93] and theoretical studies [94,95] and implies the formation of an intermediate 1,2,3-oxadiazoline complex:…”

Liquid Phase Oxidation of Alkenes with Nitrous Oxide to Carbonyl Compounds

“…1 H and 13 C NMR spectra were recorded at 400.13 and 100.61 MHz, respectively, using a Bruker MSL-400 spectrometer. The following operating conditions were used: sweep width 6 kHz ( 1 H) or 25 kHz ( 13 C), 10 ± 208 pulse of 1 ± 2 ms ( 1 H), 458 pulse of 12 ms ( 13 C), relaxation delay 5 ± 60 s. To provide an increased accuracy of measurements, large scan numbers were collected, in the range of 10 2 À 10 4 scans depending on the composition and concentration of the products.…”

“…Quantitative 13 C NMR relative intensity measurements were made with inverse gated proton decoupling (to avoid the nuclear Overhauser effect) and long relaxation delays. These results, together with the GC data, were used for calculating alkene conversions and reaction selectivities.…”

“…The following equation for the case of cyclohexene oxidation is an example: 2 This mechanism well explains the experimental data [8±11] and was supported by recent quantum-chemical calculations. [12,13] But the authors [9,10] presented no numbers for selectivity, conversion, or yield. The selectivities in refs.…”

Kinetic Studies of Catalytic Oxidation of Cyclohexene Using Chromium VI Oxide in Acetic Acid Medium

“…Ziqiang (2000) reported selective oxidation of cyclohexene to 2-cyclohexen-1-ol and 2-cyclohexen-1-one by molecular oxygen at atmospheric pressure and a temperature of 70 o C in the presence of ruthenium catalyst. N 2 O was equally reported to effectively oxidize cyclohexene in gaseous phase to cyclohexanone with nearly 100% selectivity (Avdeev et al, 2003). The kinetics of the reaction by which thallium(III) acetate oxidizes cyclohexene in glacial acetic acid medium at 30°C, was studied and reported by Leon et al, (2004).…”