Oxidation of cyclohexylamine over modified alumina by molecular oxygen

Rakottyay, Karol; Kaszonyi, Alexander

doi:10.1016/j.apcata.2009.07.034

Cited by 14 publications

(10 citation statements)

References 10 publications

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“…These broad bands represent the envelope for different absorption maxima belonging to Al-O and Al-OH bonds, both in tetrahedral and octahedral coordination, with absorption bands expected to occur in this region for amorphous c-alumina [10] (Fig. S2a).…”

Section: Catalyst Characterizationmentioning

confidence: 99%

“…The radical formed on the Schiff base can react with other Schiff base molecule to form a polymer, or by oxygen to form peroxy radical, an initiator of further oxidation or polymerization. The IR spectra of polymers-carbonaceous deposits were discussed recently [10]. Accordingly, the formation of the oligomers or polymers can block the catalysts surface.…”

Section: Extraction Of the Adsorbed Reaction Productsmentioning

confidence: 99%

“…The importance of the acidity of the supported tungsten oxide was recently reported for a non-redox application, in the glycerol carbonate formation, catalyzed by WO 3 [12]. The alumina supported tungsten oxide or silicotungstic acid catalysts were reported to exhibit as high as 70 % selectivity of cyclohexanone oxime formation at around 20 % conversion of cyclohexylamine [10].…”

mentioning

confidence: 99%

“…Further modification of alumina by aminic promoters leads to an increase in its catalytic activity; 60 % selectivity to cyclohexanone oxime at 35 % cyclohexanone conversion was observed. The main reaction products-beside cyclohexanone oxime-were cyclohexanone and a Schiff base formed by the reaction of cyclohexanone and cyclohexyl amine (N-cyclohexylidene-cyclohexylamine) [10].…”

mentioning

confidence: 99%

“…However, oxides of V, Cu, Ag and other transition metals typically occurring in redox catalysts, exhibit only a very low activity in terms of cyclohexanone oxime yields [6]. Along with the redox properties of the supported tungsten-based catalysts, the role of the acidic sites have been reported as crucial in terms of the catalytic activity [10]. On the surface of alumina-, titania-or zirconia-supported tungsten oxide, a dominant occurrence of mono-oxo wolframyl species was reported [11].…”

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confidence: 99%

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Towards the mechanism of the oxidation of cyclohexylamine by molecular oxygen over alumina-based catalysts

Horváth

Kaszonyi

Rakottyay

et al. 2015

Reac Kinet Mech Cat

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The oxidation of cyclohexylamine with molecular oxygen over a heterogeneous catalyst is an attractive one-step route to prepare a commercially important cyclohexanone oxime. The effect of the reaction conditions on the conversion of cyclohexylamine during its oxidation by molecular oxygen and on the selectivity of cyclohexanone and cyclohexanone oxime formation was investigated over heterogeneous catalysts (alumina and alumina supported silicotungstic acid). The present work is aimed at the enhancement of the cyclohexanone oxime yield, for which the optimized conditions were found as: reaction temperature of 180°C, LHSV of cyclohexylamine 1 ml g -1 h -1 , oxidant 33 % O 2 in nitrogen with a total GHSV of 24 ml min -1 . Cyclohexanone, formed from cyclohexylamine, reacts with cyclohexylamine to N-cyclohexylidenecyclohexylamine, their Schiff base. The most intense formation of cyclohexanone was observed in the initial period of the catalytic tests. Carbonaceous deposits, responsible for the catalyst deactivation, are formed mainly from the Schiff base; their amount increases by time on stream, and the rate of their formation correlates with the concentration of oxygen in the reaction mixture, as well as with the formation rate of cyclohexanone and the Schiff base. Injection of water to the reactant stream prolongs the catalyst lifetime and reduces the tar formation. However, it deteriorates the catalysts activity and selectivity. The supposed mechanism of cyclohexylamine oxidation is discussed.Electronic supplementary material The online version of this article (

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Section: Catalyst Characterizationmentioning

confidence: 99%

Section: Extraction Of the Adsorbed Reaction Productsmentioning

confidence: 99%

mentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Towards the mechanism of the oxidation of cyclohexylamine by molecular oxygen over alumina-based catalysts

Horváth

Kaszonyi

Rakottyay

et al. 2015

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SupportedTiO₂/silica gel as an efficient and inexpensive catalyst for nonsolvent liquid‐phase oxidation of cyclohexylamine to cyclohexanone oxime

Liu

Ai-yang

et al. 2022

Can J Chem Eng

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A benign approach is proposed for the highly efficient synthesis of cyclohexanone oxime through nonsolvent liquid-phase oxidation of cyclohexylamine with dioxygen over supported TiO 2 /silica gel. The as-prepared catalyst was characterized by Brunauer-Emmett-Teller (BET), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD) analyses. The results indicate that titanium active sites could be grafted on silica gel supports as catalytic centres. Various parameters such as reaction time and reaction temperature were systematically optimized; the results showed that supported 20%TiO 2 /silica gel exhibited the best catalytic effect with 63.2% of amine conversion and 86.3% of selectivity to CHO. A possible pathway is proposed for cyclohexylamine oxidation over supported TiO 2 /silica gel. The method developed in this study using dioxygen as the oxidant and inexpensive TiO 2 /silica gel as an efficient catalyst has incredible industrial application potential for green synthesis of cyclohexanone oxime.

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Oxidation of amines over alumina based catalysts

Rakottyay¹,

Kaszonyi²,

Vajíček³

2010

Applied Catalysis A: General

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Oxidation of cyclohexylamine over modified alumina by molecular oxygen

Cited by 14 publications

References 10 publications

Towards the mechanism of the oxidation of cyclohexylamine by molecular oxygen over alumina-based catalysts

Towards the mechanism of the oxidation of cyclohexylamine by molecular oxygen over alumina-based catalysts

SupportedTiO₂/silica gel as an efficient and inexpensive catalyst for nonsolvent liquid‐phase oxidation of cyclohexylamine to cyclohexanone oxime

Oxidation of amines over alumina based catalysts

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Oxidation of cyclohexylamine over modified alumina by molecular oxygen

Cited by 14 publications

References 10 publications

Towards the mechanism of the oxidation of cyclohexylamine by molecular oxygen over alumina-based catalysts

Towards the mechanism of the oxidation of cyclohexylamine by molecular oxygen over alumina-based catalysts

SupportedTiO2/silica gel as an efficient and inexpensive catalyst for nonsolvent liquid‐phase oxidation of cyclohexylamine to cyclohexanone oxime

Oxidation of amines over alumina based catalysts

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SupportedTiO₂/silica gel as an efficient and inexpensive catalyst for nonsolvent liquid‐phase oxidation of cyclohexylamine to cyclohexanone oxime