Electronic structure and chemical trans-formations of peroxides

Kokorev, V. N.; Vyshinskii, N. N.; Maslennikov, V. P.; Abronin, I. A.; Zhidomirov, G. M.; Aleksandrov, Yu. A.

doi:10.1007/bf00784076

Cited by 7 publications

(5 citation statements)

References 20 publications

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“…Francisco and Williams 19 used semiempirical MNDO calculations to derive a group additivity value of 55 ( 6 kJ mol -1 (13.1 kcal mol -1 ) for the O/O 2 group, and they used this value to calculate the enthalpy of formation of CH 3 OOOOCH 3 to be -3.8 kcal mol -1 . Using MINDO/3 semiempirical calculations, Kokorev et al 20 calculated the enthalpy of formation of CH 3 OOOOCH 3 as 6.3 kcal mol -1 , which agrees relatively well with the values suggested by Benson 15 and Nangia and Benson. 16 The radicals derived from dimethyl tetraoxide are of importance to atmospheric and combustion chemistry in their own right, and detailed thermochemistry for these species is of much usefulness.…”

Section: Introductionsupporting

confidence: 68%

“…From Table 12, we find that the best-performed functionals for enthalpies of formation from atomization reactions with the 6-31G(d) basis set are BMK, B1B95, PBE0, and B98, while with the larger basis set the most successful methods are B1B95, TPSSh, X3LYP, and PBE0. In general, the DFT methods designed to O/O2 enthalpy Benson 15 17.5 Nangia and Benson 16 16.3 Kokorev et al 20 17.7 Francisco and Williams 19 13.1 Lay and Bozzelli 17 9 study reaction kinetics outperformed those that are not. Furthermore, there is in general no significant improvement obtained by moving to the larger 6-311++G(3df,3pd) basis set.…”

Section: Resultsmentioning

confidence: 99%

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Thermochemistry, Bond Energies, and Internal Rotor Potentials of Dimethyl Tetraoxide

Silva

Bozzelli

2007

J. Phys. Chem. A

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Thermochemical properties of dimethyl tetraoxide (CH(3)OOOOCH(3)), the dimer of the methylperoxy radical, are studied using ab initio and density functional theory methods. Methylperoxy radicals are known to be important intermediates in the tropospheric ozone cycle, and the self-reaction of methylperoxy radicals, which is thought to proceed via dimethyl tetraoxide, leads to significant chain radical termination in this process. Dimethyl tetraoxide has five internal rotors, three of them unique; the potential energy profiles are calculated for these rotors, as well as for those in the CH(3)OO, CH(3)OOO, and CH(3)OOOO radicals. The dimethyl tetraoxide internal rotor profiles show barriers to rotation of 2-8 kcal mol(-1). Using B3LYP/6-31(d) geometries, frequencies, internal rotor potentials, and moments of inertia, we determine entropy and heat capacity values for dimethyl tetraoxide and its radicals. Isodesmic work reactions with the G3B3 and CBS-APNO methods are used; we calculate this enthalpy as -9.8 kcal mol(-1). Bond dissociation energies (BDEs) are calculated for all C-O and O-O bonds in dimethyl tetraoxide, again with the G3B3 and CBS-APNO theoretical methods, and we suggest the following BDEs: 46.0 kcal mol(-1) for CH(3)-OOOOCH(3), 20.0 kcal mol(-1) for CH(3)O-OOOCH(3), and 13.9 kcal mol(-1) for CH(3)OO-OOCH(3). From the BDE calculations and the isodesmic enthalpy of formation for dimethyl tetraoxide, we suggest enthalpies of 2.1, 5.8, and 1.4 kcal mol(-1) for the CH(3)OO, CH(3)OOO, and CH(3)OOOO radicals, respectively. We evaluate the suitability of 10 different density functional theory (DFT) methods for calculating thermochemical properties of dimethyl tetraoxide and its radicals with the 6-31G(d) and 6-311++G(3df,3pd) basis sets, using a variety of work reaction schemes. Overall, the best-performed DFT methods of those tested were TPSSh, BMK, and B1B95. Significant improvements in accuracy were made by moving from atomization to isodesmic work reactions, with most DFT methods yielding errors of less than 2 kcal mol(-1) with the 6-311++G(3df,3pd) basis set for isodesmic calculations on the dimethyl tetraoxide enthalpy. These isodesmic calculations were basis set consistent, with a considerable reduction in error found by using the 6-311++G(3df,3pd) basis set over the 6-31G(d) basis set. This was not the case, however, for atomization and bond dissociation work reactions, where the two basis sets returned similar results. Improved group additivity terms for the O-O-O moiety (O/O2 central atom group) are also determined.

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Section: Introductionsupporting

confidence: 68%

Section: Resultsmentioning

confidence: 99%

Thermochemistry, Bond Energies, and Internal Rotor Potentials of Dimethyl Tetraoxide

Silva

Bozzelli

2007

J. Phys. Chem. A

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“…These data were obtained using the group contribution approach. Some physicochemical and geometric parameters were calculated for the methyl hydrotetraoxide molecule as a model compound [21,22,23]. The IR spectra of dimethyl tetraoxide with isotopically labeled groups in Ar-O2 matrices were also reported [24].…”

Section: Romentioning

confidence: 99%

Kinetics of Nonbranched-Chain Oxidation Involving 1:2 Adduct Radicals <img src=image/tit1.png></img> and <img src=image/tit2.png></img>

Silaev¹

2014

CES

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New reaction scheme is suggested for the initiated nonbranched-chain addition of free radicals to the multiple bond of the molecular oxygen. The scheme includes the reaction competing with chain propagation reactions through a reactive free radical. The chain evolution stage in this scheme involves a few of free radicals, one of which (tetraoxyl) is relatively low-reactive and inhibits the chain process by shortening of the kinetic chain length. Based on the proposed scheme rate equations (containing one to three parameters to be determined directly) are deduced using quasi-steady-state treatment. The kinetic description with use the obtained rate equations is applied to the γ-induced nonbranched-chain processes of the free-radical oxidation of liquid o-xylene at 373 K and hydrogen dissolved in water containing different amounts of oxygen at 296 K. In these processes the oxygen with the increase of its concentration begins to act as an oxidation autoingibitor (or an antioxidant), and the rate of peroxide formation as a function of the dissolved oxygen concentration has a maximum. The heat effects are compared for the overall reactions of dissociation of simple alkylperoxyl (exothermic) and alkoxyl (endothermic) free radicals in the gas phase. Possible nonchain pathways of the free-radical oxidation of hydrogen and the routes of ozone decay from the energetic standpoint via the reaction with the hydroxyl free radical in the upper atmosphere (including the addition yielding the hydrotetraoxyl free radical, which can be an intermediate in the sequence of conversions of biologically hazardous UV radiation energy) were examined. The energetics of the key radical-molecule reactions is considered.

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“…Orbital consideration and quantum-chemical calculations 2,84 allow the conclusion that the directing influence of a hydroxy group is due to the interaction of the leaving anion of the acid with the hydrogen atom of the hydroxy group during decomposition of the activated complex 90 (Fig. 3).…”

Section: Hooocrmentioning

confidence: 99%

Mechanism of the directing influence of functional groups and the geometry of reactant molecules on peroxide epoxidation of alkenes

Dryuk¹,

Карцев²

1999

Russ. Chem. Rev.

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The influence of steric and electronic factors on the reactivity and the stereochemical outcome of epoxidation of cycloalkenes and prochiral alkenes by alkyl hydroperoxides, peroxy acids, oxaziridines, dioxiranes and dimethyl-a-peroxy lactone is analysed comparatively and generalised. The distinctive features of the directing influence of functional groups on the stereochemistry of the epoxide ring closure in the series of ionic, radical and molecular reactions are demonstrated. Some variants alternative to known reaction mechanisms are proposed. The bibliography includes 114 references.

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Electronic structure and chemical trans-formations of peroxides

Cited by 7 publications

References 20 publications

Thermochemistry, Bond Energies, and Internal Rotor Potentials of Dimethyl Tetraoxide

Thermochemistry, Bond Energies, and Internal Rotor Potentials of Dimethyl Tetraoxide

Kinetics of Nonbranched-Chain Oxidation Involving 1:2 Adduct Radicals <img src=image/tit1.png></img> and <img src=image/tit2.png></img>

Mechanism of the directing influence of functional groups and the geometry of reactant molecules on peroxide epoxidation of alkenes

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