Mechanisms of the formation of carboxylic acids and their anhydrides during the liquid-phase oxidation of cyclohexane

Perkel, A. L.; Voronina, S. G.

doi:10.1007/s11172-019-2582-4

Cited by 9 publications

(6 citation statements)

References 45 publications

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“…Peroxyl radical (6), which is formed upon oxidation of the ester acyl moiety at the β-СН bond, isomerizes into carbon-centered radical 8 via transition state 7 (Scheme 3). 40…”

Section: Methodsmentioning

confidence: 99%

“…In particular, α-benzoyloxibenzyl peroxyl (PhC (O)-OCH(OO • )Ph) and α-carboxy-tert-butylbenzyl peroxyl (PhCH(OO • )C(O)OBu t ) radicals are 306 and respectively 27 times as active in the reactions with corresponding esters at 303 K, than tert-butyl peroxyl radicals (Bu t OO • ) (Table 1). [54][55][56] Peroxyl radicals (1) with suffi ciently long aliphatic chains in the ester acyl or alkoxyl moieties can isomerize via a six-or seven-membered transition state into radicals of type 2 (Scheme 2, reaction (6)). These radicals are transformed into β-and γ-dihydroperoxides of type 4 (Scheme 2, reaction (7)) or hydroperoxy ketones of type 5 (Scheme 2, reacion ( 8)) via hydroperoxyperoxyl radicals 3.…”

Section: Elementary Steps and Kinetics Of Radical-chain Oxidation Of Estersmentioning

confidence: 99%

“…Esters of secondary and primary alcohols are formed as side products of the liquid-phase oxidation of cyclo-hexane, other saturated hydrocarbons, and their oxygencontaining derivatives. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Monocarboxylic, dicarboxylic acids, and ω-hydroxycarboxylic acids, aldehydes, and diols can be obtained by a direct oxidation of esters. 11,16 The use of esters as solvents, softeners, and components of lubricating oils is accompanied by a loss of operational properties due to thermal oxidative destruction of these compounds.…”

Section: Introductionmentioning

confidence: 99%

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The specific features of the liquid-phase oxidation of saturated esters. Kinetics, reactivity and mechanisms of formation of destruction products

Perkel

Voronina

2020

Russ Chem Bull

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Data on kinetics, reactivity, and mechanisms of formation of destruction products of the liquid-phase oxidation of saturated esters by molecular oxygen have been systematized and discussed. The ester group has both an activating and deactivating eff ects on the reactivity of the СН bonds of the alkoxyl (α´-, β´-, γ´-, and δ´-) and acyl (α-, β-, and γ-) groups. The activating eff ect in esters is weaker than in alcohols, ketones, and ethers and extends to the αand α´-CH bonds. The reactivity of the β-, β´-, and γ´-СН bonds is signifi cantly lower than that of the secondary СН bonds of hydrocarbons. Oxidation of the β-СН bonds of the acyl moieties of esters leads to НОО • radical, α,β-epoxy-, α,β-dihydroxy-, and α,β-unsaturated esters, but not to hydroperoxides. Upon the oxidation of esters, the highly active α-carboxyalkylperoxy-, α-acyloxyperoxy-, and НОО • -radicals are formed. The recombination reactions involving these radicals occur both with and without chain termination. The specifi city of the decomposition of ester hydroperoxides are due to intra-and intermolecular interactions of the hydroperoxide groups with the ester groups. Labile peroxide intermediates (α-hydroxyperoxyesters, peroxyesters, and peroxylactones) are formed through the corresponding tetrahedral intermediates and decay predominantly by the non-radical pathway. The recombination of the peroxyl radicals and the decay of labile peroxides result in the parallel accumulation of per oxide and non-peroxide products during the oxidation of esters.

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“…Peroxyl radical (6), which is formed upon oxidation of the ester acyl moiety at the β-СН bond, isomerizes into carbon-centered radical 8 via transition state 7 (Scheme 3). 40…”

Section: Methodsmentioning

confidence: 99%

Section: Elementary Steps and Kinetics Of Radical-chain Oxidation Of Estersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The specific features of the liquid-phase oxidation of saturated esters. Kinetics, reactivity and mechanisms of formation of destruction products

Perkel

Voronina

2020

Russ Chem Bull

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“…Циклогексанон -важнейший полупродукт промышленного органического синтеза, получаемый жидкофазным окислением циклогексана [1][2][3][4].…”

Section: ключевые слова: циклогексанон конформации «кресло» «ванна» к...unclassified

“…Вместе с тем наименьшая энергия этой конформации является причиной ее наименьшей реакционной способности из всех конформаций циклогексанона в реакциях окисления [9]. Так как окисление циклогексанона в процессе окисления циклогексана -основная причина снижения селективности [1][2][3][4][10][11][12][13][14], исследование закономерностей переходов циклогексанона в более реакционноспособные конформации представляется достаточно актуальным. Поскольку наиболее вероятен переход циклогексанона из конформации «кресло» в конформацию «ванна», обладающую меньшей энергией из всех прочих конформаций кетона [5][6][7][8][9], в настоящей работе были изучены закономерности конформационного перехода «кресло»-«ванна».…”

Section: ключевые слова: циклогексанон конформации «кресло» «ванна» к...unclassified

About Formation and Structure of Transition State During "Chair" to "Boat" Transition of Cyclohexanone

Пучков

Nepomnyashchikh

2022

Vestn. Kuzbasskogo gos. teh. univ.

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By the density functional theory (DFT) method of with hybrid functional B3LYP in the basis 6-31G for the cyclohexanone molecule, a scan was carried out on the coordinate of the conformational transition "chair"-"boat". It has been shown that such a "chair"-" boat" transition energetically more preferably proceeds through a change in the geometric parameters of the "carbonyl" fragment of the ketone molecule. By the QST2 and QST3 methods (Quadratic Synchronous Transit Approach) the transition state of the conformational transition "chair"-"boat" of the cyclohexanone molecule is localized. There was confirmed that all structures are stationary points on the surface of potential energy. Geometric characteristics of the transition state of the conformational transition "chair"-"boat" of the cyclohexanone molecule are determined: bond lengths and valence angles. The geometry of the transition state of the conformational transition "chair"-"boat" was close to the geometry of the conformation "sofa" of the cyclohexanone molecule. The total energies of the transition state of the conformational transition "chair"-"boat" and the conformations "chair" and "boat" of cyclohexanone are calculated. The activation energies of the direct and reverse reactions of the conformational transition "chair" -"boat" are calculated. It is shown that the transition "chair"-"boat" is an endothermic reaction, and the return transition "boat"-"chair" is exothermic. The conformation energy of the cyclohexanone "boat" is 16.3 kJ/mol higher than the conformation energy of the "chair".For citation Puchkov S.V., Nepomnyashchikh Yu.V. About formation and structure of transition state during "chair" to "boat" transition of cyclohexanone.

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Mechanisms for the formation of ester compounds in the liquid-phase oxidation of cyclohexane

Perkel

Voronina

2019

Russ Chem Bull

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Mechanisms of the formation of carboxylic acids and their anhydrides during the liquid-phase oxidation of cyclohexane

Cited by 9 publications

References 45 publications

The specific features of the liquid-phase oxidation of saturated esters. Kinetics, reactivity and mechanisms of formation of destruction products

The specific features of the liquid-phase oxidation of saturated esters. Kinetics, reactivity and mechanisms of formation of destruction products

About Formation and Structure of Transition State During "Chair" to "Boat" Transition of Cyclohexanone

Mechanisms for the formation of ester compounds in the liquid-phase oxidation of cyclohexane

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