Thermochemistry and kinetics of ozonation reactions

Nangia, Prakash S.; Benson, Sidney W.

doi:10.1021/ja00529a037

Cited by 105 publications

(59 citation statements)

References 9 publications

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“…From IIa and IIIb with the stabilization of hydration in Table 7, the ground-electronic structures of unsymmetrical oxygenated dipoles with polar substituents are probably ZW in polar solution, compatible with Crigee's proposal [1]. Other theoretical studies (Harding and Goddard [25], Houk et al [27], Nangia and Benson [28], and Cremer et al [17e] indicate similar tendencies. The closed-shell RHF results provide reasonable descriptions of the ZW states of the species since the RHF solutions converge to the states.…”

Section: Figure 2 a Plot Of The Energy Difference Between Zw And Br supporting

confidence: 75%

“…Namely, it exists even in water. The same situation appears in the case of the second and third steps of the ozonolysis reactions discussed by Nangia and Benson [28], and Fliszar and Carles [3]. Thus solvation effects are important when accounting for the various aspects of ozonolysis reactions in the solution phases and will be discussed in detail elsewhere.…”

Section: Figure 2 a Plot Of The Energy Difference Between Zw And Br mentioning

confidence: 67%

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Theoretical study on electronic structures of oxygenated dipoles and mechanisms of ozonolysis reactions

Yoshioka

Yamaki

Kubo

et al. 1997

Elect J Theoret Chem

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SUMMARYThe different orbitals for different spins molecular orbital and complete active space SCF studies of ozone and carbonyl oxide and related ozonolysis reactions were carried out. The RHF, UHF, approximately spin-projected (AP) UHF and CASSCF calculations were performed to elucidate the covalent bond instability of the oxygenated dipoles. The correlation energies were calculated by RMP4, UMP4, APUMP4 and CASPT2 methods. The locations of concerted transition structures for ozonolysis reactions and the full geometry optimizations of 1,5 biradicals formed by the O-O cleavage of first ozonide were carried out. The implications of these results are discussed in relation to concerted and biradical mechanisms of 1,3-dipolar additions and ozonolyses in gas phases.

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Section: Figure 2 a Plot Of The Energy Difference Between Zw And Br supporting

confidence: 75%

Section: Figure 2 a Plot Of The Energy Difference Between Zw And Br mentioning

confidence: 67%

Theoretical study on electronic structures of oxygenated dipoles and mechanisms of ozonolysis reactions

Yoshioka

Yamaki

Kubo

et al. 1997

Elect J Theoret Chem

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“…There appear to be no steric or energetic impediments to the formation of 2: all the available evidence indicates that the reaction between ozone and 12 forms the molozonide; the methoxy group is considered to be less sterically demanding than the methyl group (17,18); and the reaction to form 2 can be calculated, using group additivity values (18)(19)(20), to be exothermic by 71 kcal/mol. Thus, there must be another reaction that intervenes as the molecules of ozone and 1 approach each other.…”

Section: Initial Electron Transfermentioning

confidence: 99%

“…The reaction of eq. [4] has been calculated to be endothermic by 11 kcal/mol, while the corresponding, spin forbidden, reaction to form triplet oxygen is exothermic by 11 kcal/mol (19). The energetics of the fragmentation of 21 to 15 and oxygen should be similar.…”

Section: Initial Electron Transfermentioning

confidence: 99%

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Ozonolysis of tetramethoxyethene

Kopecky¹,

Molina²,

Rico³

1988

Can. J. Chem.

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. Can. J. Chem. 66, 2234Chem. 66, (1988. Ozonolysis of tetramethoxyethene 1 produces 20-40% of dimethyl carbonate 3, 35-60% of methyl trimethoxyacetate 7, and 20-35% of the dioxetane 8 of 1. Yields vary with initial concentration of 1, temperature, and solvent. Singlet oxygen is produced, which reacts with 1 to form 8 and can be trapped with 2,5-dimethylfuran. No evidence for the formation of the molozonide of 1 was obtained. Up to 2.5 moles of 1 are consumed per mole of ozone. Ozonolysis of a mixture of 1 and 2,3-dimethyl-2-butene 12 gave the epoxide of 12 and three times the expected amount of the allylic hydroperoxide of 12. A competing radical chain oxidation reaction is proposed to account for these products and the stoichiometry of the ozonolysis. The initial reaction in the ozonolysis of 1 is proposed to be an electron transfer reaction that is calculated to be exothermic by >35 kcal/mol. The resulting radical ions initiate the radical chain oxidation and combine to form the oxygenated epoxide 9 of 1. Loss of singlet oxygen from 9 forms the epoxide 10, which rearranges to 7. At -95'C the zwitterion from 10 is trapped by CD30D to produce a mixture of 7 with one a 0CD3 group and pentamethoxyethanol with one P 0CD3 group from which a CH30D group is lost at --10°C to form more deuterated ester. L'ozonolyse du tCtramCthoxyCthkne (1) foumit de 20 40% de carbonate de dimdthyle (3), de 35 a 60% de trimCthoxyacCtate de mtthyle (7) et de 20 a 35% du dioxCtane 8 du compost5 1. Les rendements varient avec la concentration initiale du composC 1, avec la temperature et avec le solvant. I1 se produit de I'oxygkne singulet qui rCagit avec le compost 1 pour donner du produit 8; on peut le pitger avec du dimithyl-2,5 furanne. On n'a pas obtenu de rCsultats suggCrant qu'il se forme du molozonide du composC 1. Pour chaque molCcule d'ozone, il y a 2,5 moles du composC 1 qui sont consommCes. L'ozonolyse d'un mClange du composC 1 et du dimethyl-2,3 butkne-2 (12) fournit 1'Cpoxyde 12 ainsi que de I'hydroperoxyde allylique de 12 qui se forme en quantitts trois fois plus grandes que ce qu'on avait prCvu. On suggkre I'existence d'une reaction competitive d'oxydation radicalaire en chaine pour expliquer la formation de ces produits ainsi que la stoechiomttrie de l'ozonolyse. On suggkre que la rtaction initiale, lors de l'ozonolyse du composC 1, est une rCaction de transfert Clectronique qui, d'aprks nos calculs, serait exothermique par >35 kcal/mol. Les ions radicaux qui en rCsultent initient la reaction d70xydation radicalaire en chaine et se combinent pour former l'tpoxyde oxygCne 9 du composC 1. Par perte d'oxygkne singulet, le composC 9 foumit 1'Cpoxyde 10 qui se transpose en composC 7. A -95"C, le zwitterion provenant du compost 10 est piCgC par le CD30D pour conduire a un mClange du composC 7 portant un groupement 0CD3 en a et de pentamCthoxyCthano1 portant un groupement 0CD3 en P qui, par perte de CH30D a --1O0C, forme d'autre ester deutCrC.[Traduit par la revue] IntroductionA general synthesis of tetraalkoxy-1,2,4,5-tetrox...

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Formation of hydrotrioxides during ozonation of hydrocarbons on silica gel. Decomposition of hydrotrioxides

Avzyanova

Timerghazin

Khalizov

et al. 2000

J. Phys. Org. Chem.

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Hydrotrioxides (HT), ROOOH, from isopentane, 1,4-dimethylcyclohexane, 1,3-dimethylcyclohexane, decalin and triphenylmethane were synthesized for the first time by low-temperature ozonation of the corresponding hydrocarbons on a silica surface. Thermal decomposition of hydrotrioxides is accompanied by the formation of radicals and by infrared and visible chemiluminescence (CL). In solution the HTs form self-associates and react reversibly with the solvent (acetone) producing Bayer-Villiger type intermediates (unsymmetrical dialkyl trioxides). These reactions cause a complex character of the decomposition kinetics of HTs, as evidenced by monitoring the dependence of CL intensity on time. Activation parameters of thermal decomposition of HTs show a compensation effect (logA vs E A ) which describes well the available experimental and theoretical data for the homolysis of organic trioxides.

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Thermochemistry and kinetics of ozonation reactions

Cited by 105 publications

References 9 publications

Theoretical study on electronic structures of oxygenated dipoles and mechanisms of ozonolysis reactions

Theoretical study on electronic structures of oxygenated dipoles and mechanisms of ozonolysis reactions

Ozonolysis of tetramethoxyethene

Formation of hydrotrioxides during ozonation of hydrocarbons on silica gel. Decomposition of hydrotrioxides

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