The thermochemistry of polyoxides and polyoxy radicals

Francisco, Joseph S.; Williams, Ian H.

doi:10.1002/kin.550200605

Cited by 61 publications

(45 citation statements)

References 45 publications

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“…Reaction 4 in the case of the methylperoxyl radical 3 2 CH O  adding to the oxygen molecule to yield the methyltetraoxyl radical 3 4 CH O  takes place in the gas phase, with heat absorption equal to 110.0 ± 18.6 kJ mol -1 [49] (without the energy of the possible formation of a hydrogen bond taken into account). The exothermic reactions 6 and 7, in which the radical R • or 4 RO  undergoes disproportionation, include the isomerization and decomposition of the 4 RO  radical.…”

Section: Methodsmentioning

confidence: 99%

“…Nonbranched-chain oxidation of hydrogen and changes in enthalpy (ΔН˚2 98 , kJ mol -1 ) for elementary reactions 10 10 According to Francisco and Williams [49], the enthalpy of formation HO radical with a helical structure were carried out using the G2(MP2) method [68]. The stabilization energies of HO were calculated in the same work to be 64.5  0.1, 69.5  0.8, and 88.5  0.8 kJ mol -1 , respectively.…”

Section: Methodsmentioning

confidence: 99%

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Kinetics of Nonbranched-Chain Processes of the Free-Radical Addition to Molecules of Alkenes, Formaldehyde, and Oxygen with Competing Reactions of Resulting 1:1 Adduct Radicals with Saturated and Unsaturated Components of the Binary Reaction System

Silaev¹

2017

IJIREM

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Five reaction schemes are suggested for the initiated nonbranchedchain addition of free radicals to the multiple bonds of the unsaturated compounds. The proposed schemes include the reaction competing with chain propagation reactions through a reactive free radical. The chain evolution stage in these schemes involves three or four types of free radicals. One of them is relatively low-reactive and inhibits the chain process by shortening of the kinetic chain length. Based on the suggested schemes, nine rate equations (containing one to three parameters to be determined directly) are deduced using quasi-steady-state treatment. These equations provide good fits for the nonmonotonic (peaking) dependences of the formation rates of the molecular products (1:1 adducts) on the concentration of the unsaturated component in binary systems consisting of a saturated component (hydrocarbon, alcohol, etc.) and an unsaturated component (alkene, allyl alcohol, formaldehyde, or dioxygen). The unsaturated compound in these systems is both a reactant and an autoinhibitor generating low-reactive free radicals. A similar kinetic description is applicable to the nonbranched-chain process of the free-radical hydrogen oxidation, in which the oxygen with the increase of its concentration begins to act as an oxidation autoingibitor (or an antioxidant). The energetics of the key radicalmolecule reactions is considered.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Kinetics of Nonbranched-Chain Processes of the Free-Radical Addition to Molecules of Alkenes, Formaldehyde, and Oxygen with Competing Reactions of Resulting 1:1 Adduct Radicals with Saturated and Unsaturated Components of the Binary Reaction System

Silaev¹

2017

IJIREM

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“…At later stages of oxidation and at sufficiently high temperatures, the resulting aldehydes can be further oxidized into respective carboxylic acids. They can also react with molecular oxygen so that a C-H bond in the aldehyde molecule breaks to yield two free of the possible intramolecular hydrogen bond Н···О taken into account is ΔНf˚298( [20]. These data were obtained using the group contribution approach.…”

Section: Methodsmentioning

confidence: 99%

“…9 According to Francisco and Williams [20], the enthalpy of formation HO radical with a helical structure were carried out using the G2(MP2) method [39]. The stabilization energies of HO were calculated in the same work to be 64.5  0.1, 69.5  0.8, and 88.5  0.8 kJ mol -1 , respectively.…”

Section: Methodsmentioning

confidence: 99%

A New Mechanism of Free-Radical Nonbranched-Chain Oxidation: Oxygen as an Antioxidant

Silae¹

2017

IJIRCST

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“…At later stages of oxidation and at sufficiently high temperatures, the resulting aldehydes can be further oxidized into respective carboxylic acids. They can also react with molecular oxygen 5 Thermochemical data are available for some polyoxyl free radicals (the enthalpy of formation of the methyltetraoxyl radical without the energy of the possible intramolecular hydrogen bond Н···О taken into account is ) [49]. These data were obtained using the group contribution approach.…”

Section: Romentioning

confidence: 99%

Competition Kinetics of the Non-branched-Chain Processes of Free Radical Addition to the C=C, C=O, and O=O Bonds of Molecules<SUP>1</SUP>

Silaev¹

2012

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The aim of our study was the conclusion of the simple kinetic equations to describe ab initio the initiated non-branched-chain processes of saturated free radical addition to C=C, C=O, and O=O bonds of molecules in the binary systems of saturated and unsaturated components. In the processes of this kind the formation rate of the molecular addition products (1:1 adducts) as a function of concentration of the unsaturated component has a maximum. Five reaction schemes are suggested for addition processes of free radicals to the multiple bonds of molecules. The schemes include reactions competing with chain propagation through a reactive free radical. The chain evolution stage in these schemes involves three or four types of free radicals, of which one is relatively low-reactive and inhibits the chain process by shortening of the kinetic chain length. Based on the suggested schemes, nine rate equations containing one to three parameters to be determined directly are set up using quasi-steady-state treatment. These equations provide good fits for the non-monotonic (peaking) dependences of the formation rates of the molecular 1:1 adducts on the concentration of the unsaturated component in liquid homogeneous binary systems consisting of a saturated component (hydrocarbon, alcohol, etc.) and an unsaturated component (olefin, allyl alcohol, formaldehyde, or dioxygen). The unsaturated compound in these systems is both a reactant and an autoinhibitor generating low-reactive free radicals such as СН 2 =С(СН 3 )ĊН 2 , СН 2 =СНĊНОН, НĊ=O, o-СН 3 С 6 Н 4 СН 2 4 O  , or 4 HO  . A similar kinetic description is applicable to non-branched-chain free-radical hydrogen oxidation. The energetics of the key radical-molecule reactions is considered.

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The thermochemistry of polyoxides and polyoxy radicals

Cited by 61 publications

References 45 publications

Kinetics of Nonbranched-Chain Processes of the Free-Radical Addition to Molecules of Alkenes, Formaldehyde, and Oxygen with Competing Reactions of Resulting 1:1 Adduct Radicals with Saturated and Unsaturated Components of the Binary Reaction System

Kinetics of Nonbranched-Chain Processes of the Free-Radical Addition to Molecules of Alkenes, Formaldehyde, and Oxygen with Competing Reactions of Resulting 1:1 Adduct Radicals with Saturated and Unsaturated Components of the Binary Reaction System

A New Mechanism of Free-Radical Nonbranched-Chain Oxidation: Oxygen as an Antioxidant

Competition Kinetics of the Non-branched-Chain Processes of Free Radical Addition to the C=C, C=O, and O=O Bonds of Molecules<SUP>1</SUP>

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