Reaction d'oximation des cetones iv.

Lamaty, G.; Roque, J. P.; Natat, A.; Silou, T.

doi:10.1016/s0040-4020(01)90551-4

Cited by 4 publications

(2 citation statements)

References 16 publications

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“…pH 9 [11,12]. Equilibrium constants for the formation of ketone-hydroxylamine adducts and rate constants for the dehydration of the intermediates were measured in H 2 O-MeOH (6:4) at room temperature [13]. Secondary amines were found to catalyze the oximation of acetone [11,12].…”

Section: Introductionmentioning

confidence: 99%

A Study of the pH Dependence of the Two‐Step Oximation of Acetone by in situ Fourier Transform Infrared Spectroscopy

Keglevich¹,

Csontos²,

Szilágyi³

et al. 2008

Chem Eng & Technol

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In situ Fourier transform IR spectroscopy has been found to be an appropriate tool for the evaluation, monitoring and optimization of the pH dependent and two-step oximation of acetone in water. When carrying out the reaction at 5°C, the intermediate formation of the acetone-hydroxylamine adduct (2) was observed at pH 8.5, while at pH 10, the oxime (3) was formed almost instantly. Identification of the intermediate (2) was promoted by the IR spectrum obtained by B3LYP/6-31++G(d,p)//PCM calculations. At pH ∼ 2.5, the protonated form of the oxime (3') developed gradually, but the intermediate (2) could not be observed. The pH dependence of the stability of the intermediate (2) and the (3' → 3) and (3 → 3') interconversions were studied in separate experiments. An equilibrium was observed in the latter case.

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Section: Introductionmentioning

confidence: 99%

A Study of the pH Dependence of the Two‐Step Oximation of Acetone by in situ Fourier Transform Infrared Spectroscopy

Keglevich¹,

Csontos²,

Szilágyi³

et al. 2008

Chem Eng & Technol

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“…When the dehydration is the ratedetermining step, considering that both species of salicylaldehyde (dissociated and non-dissociated) give approximately the same value of their equilibrium constant with the addition intermediate formed with hydroxylamine, the rate law has the form indicated in eqn. (1). and kBKa, are the kcapp (apparent catalytic constants) given in Table 1.…”

Section: Methodsmentioning

confidence: 99%

The effect of boric acid on the dehydration step in the formation of oxime from salicylaldehyde

Simionatto¹,

Yunes²,

Yunes³

1993

J. Chem. Soc., Perkin Trans. 2

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Addition of hydroxylamine to cyclohexanone and bicyclic ketones. Steric, electronic and hydrogen bonding effects on the general mechanism of addition of amines to carbonyl compounds

Brighente

Vottero

Terezani

et al. 1991

J of Physical Organic Chem

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Three different types of pH-rate profiles were observed for the addition of amines to carbonyl compounds, depending on the relative predominance, at weakly acidic pH, of either a concerted or a stepwise mechanism. The predominant mechanism depends on the basicity of the amine and the mutual equilibrium affinity for adduct formation between the carbonyl compound and the amine. The reaction of hydroxylamine with cyclohexanone and bicyclic ketones was studied in order to examine the roles of steric and electronic effects in this mechanism. Cyclohexanone and 3chlorobicyclo [2.2.1] heptan-2-one exhibit the profile expected for a single change in the rate-determining step with increasing pH from uncatalysed attack of the amine on the carbonyl group to hydronium ion-catalysed dehydration of the carbinolamine. In contrast, both bicyclo [2.2.1] heptan-2-one and hicyclo [2.2.2] octan-2-one show an unexpected profile with two negative breaks and five kinetically significant regions. This profile is explained by stabilization of the zwitterionic intermediate T' by intramolecular hydrogen bonding, leading to the formation of the carbinolamine by a stepwise mechanism at weakly acidic pH.

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Reaction d'oximation des cetones iv.

Cited by 4 publications

References 16 publications

A Study of the pH Dependence of the Two‐Step Oximation of Acetone by in situ Fourier Transform Infrared Spectroscopy

A Study of the pH Dependence of the Two‐Step Oximation of Acetone by in situ Fourier Transform Infrared Spectroscopy

The effect of boric acid on the dehydration step in the formation of oxime from salicylaldehyde

Addition of hydroxylamine to cyclohexanone and bicyclic ketones. Steric, electronic and hydrogen bonding effects on the general mechanism of addition of amines to carbonyl compounds

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