Reactions of Methyl Radicals with Substrates Acting as Hydrogen Donors and as Methyl Radical Acceptors

Buckley, R. P.; Leavitt, F.; Szwarc, M.

doi:10.1021/ja01602a025

Cited by 36 publications

(11 citation statements)

References 1 publication

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“…We have compiled the limited data available in Table 8•13. [25][26][27][28][29][30][31][32][33][34][35][36][37][38] The data do indeed suggest that the polar character of the radical determines its abstraction/addition ratio; the table shows the following trend for the rate constant ratio fcadd/fcH.abstract: P'N02Ph b The hydrogen atom reacts with both benzene and toluenes at rapid rates. c The yield of the addition product is approximated by the deficit in the yield of CH"; the yield of abstraction is obtained from the CH" yields.…”

Section: Resultsmentioning

confidence: 99%

Chemistry of the tert-butyl radical: polar character, .rho. value for reaction with toluenes, and the effect of radical polarity on the ratio of benzylic hydrogen abstraction to addition to aromatic rings

Pryor¹,

Tang²,

Tang³

et al. 1982

J. Am. Chem. Soc.

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We have reexamined the reactions of tert-butyl radicals with toluenes and have obtained a p value of 0.49 f 0.04 at 80 O C . The new, independent system involves the quantification of all of the principal products from the reaction of tert-butyl radicals with mixtures of toluene and a substituted toluene. Five major products contain benzyl fragments and are formed in significant yields: two symmetrical bibenzyls, the cross bibenzyl, and the two neopentylbenzenes that result from combination of tert-butyl and the two benzyl radicals. Attack on the side chain is a major reaction of free tert-butyl radicals and is the only significant reaction that they undergo other than cage and termination reactions. tert-Butyl radicals do not add to the ring of toluenes. Data on the relative rates of addition to benzenes and hydrogen abstraction from toluenes are collected for a series of radicals including hydrogen atoms; methyl, isopropyl, and tert-butyl radicals; and p-nitrophenyl, p-bromophenyl, and phenyl radicals. The data demonstrate that more electrophilic radicals have a larger tendency to add to rings whereas more nucleophilic radicals have a larger tendency to abstract benzylic hydrogens.

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Section: Resultsmentioning

confidence: 99%

Chemistry of the tert-butyl radical: polar character, .rho. value for reaction with toluenes, and the effect of radical polarity on the ratio of benzylic hydrogen abstraction to addition to aromatic rings

Pryor¹,

Tang²,

Tang³

et al. 1982

J. Am. Chem. Soc.

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“…The methyl radical formation in the p-xylene oxidation process is evidenced by the presence of CH4 in the off-gases and of methanol and methyl acetate in the mother liquor. This radical has much chance of adding to an aromatic nucleus yielding trialkylbenzenes, since its addition to the benzene ring is only 3 or 4 times slower than hydrogen abstraction from a CH3 group of an aromatic compound (Buckley et al, 1956;Heiba et al, 1968). The acetic acid decomposition caused by manganese(III), the other component of the catalytic system, has been found to produce the • 2 radical (Finkbeiner and Bush, 1968; Van der Ploeg et al, 1968).…”

Section: B*[fex3br]mentioning

confidence: 99%

Byproduct identification in the terephthalic acid production process and possible mechanisms of their formation

Roffia¹,

Calini²,

Motta³

et al. 1984

Ind. Eng. Chem. Prod. Res. Dev.

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Ind. Eng. Chem. Prod. Res. Dev. 1984, 23, 629-634 629 cyclo[2.2.2]octane, 1449-91-8; trans-2-chloro-5-(chloromethyl)-5methyl-2-oxo-l,3,2-dioxaphosphorinane, 21071-81-8; cis-2-methoxy-5-(chloromethyl)-5-methyl-2-oxo-l,3,2-dioxaphosphorinane, 28097-12-3; trans-2-methoxy-5-(chloromethyl)-5-methyl-2-oxo-1,3,2-dioxaphosphorinane, 36912-27-3; cis-2-hydroxy-5-(chloromethyl)-5-methyl-2-oxo-1,3,2-dioxaphosphorinane, 36912-29-5; cis-2-phenoxy-5-(chloromethyl)-5-methyl-2-oxo-1,3,2-dioxaphosphorinane, 36912-30-8; trans-2-phenoxy-5-(chloromethyl)-5methyl-2-oxo-1,3,2-dioxaphosphorinane, 36895-18-8; cis-2-(4methoxyphenoxy)-5-(chloromethyl)-5-methyl-2-oxo-l,3,2-dioxaphosphorinane, 36912-31-9; trans-2-(4-methoxyphenoxy)-5-(chloromethyl)-5-methyl-2-oxo-1,3,2-dioxaphosphorinane, 36912-32-0; cis-2-(4-methylphenoxy)-5-(chloromethyl)-5methyl-2-oxo-1,3,2-dioxaphosphorinane, 36912-33-1; trans-2-(4methylphenoxy)-5-(chloromethyl)-5-methyl-2-oxo-1,3,2-dioxaphosphorinane, 36912-34-2; cis-2-(4-bromophenoxy)-5-(chloromethyl)-5-methyl-2-oxo-1,3,2-dioxaphosporinane, 36912-35-3; trans-2-(4-bromophenoxy)-5-(chloromethyl)-5-methyl-2-oxo-1,3,2-dioxaphosphorinane, 36912-36-4; cis-2-(4-nitrophenoxy)-5-(chloromethyl)-5-methyl-2-oxo-l,3,2-dioxaphosphorinane, 36912-37-5; trans-2-(4-nitrophenoxy)-5-(chloromethyl)-5methyl-2-oxo-1,3,2-dioxaphosphorinane, 36912-38-6; cis-2-(2,4dinitrophenoxy)-5-(chloromethyl)-5-methyl-2-oxo-1,3,2-dioxaphosphorinane, 36912-39-7; trans-2-(2,4-dinitrophenoxy)-5-(chloromethyl)-5-methyl-2-oxo-l,3,2-dioxaphosphorinane, 36912-40-0; cis-2-benzoyloxy-5-(chloromethyl)-5-methyl-2-oxo-1,3,2-dioxaphosphosphorinane, 36912-41-1; trans-2-benzoyloxy-5-(chloromethyl)-5-methyl-2-oxo-1,3,2-dioxaphosphorinane, 36912-42-2; cis-2-thiophenoxy-5-(chloromethyl)-5-methyl-2-oxo-1,3,2-dioxaphosphorinane, 36912-43-3; trans-2-thiophenoxy-5-(chloromethyl)-5-methyl-2-oxo-l,3,2-dioxaphosphorinane, 36912-44-4; cis-2-(pentylamino)-5-(chloromethyl)-5-methyl-2oxo-1,3,2-dioxaphosphorinane, 92366-30-8; trans-2-(pentylamino)-5-(chloromethyl)-5-methyl-2-oxo-1,3,2-dioxaphosphorinane, 92366-31-9; trans-2-(4-acetylphenoxy)-5-(chloromethyl)-5methyl-2-oxo-1,3,2-dioxaphosphorinane, 92366-32-0. Literature Cited Bauman, M.; Wadsworth, W. S., Jr. J . Am. Chem. SOC. 1978, 100, 6380. Gillespie, P.; Ramirez, F.; Ugi, 1.; Marquarding, D. Angew. Chem., Int. Ed. Engl. 1973, 12, 91. Rajan, S.; Kang, S.; Gutowsky, H.; Oidfield, E. J . 8/01,

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“…It has been proposed (1 1, 12) for radical addition reactions to olefins addition of methyl radicals to olefins (14)(15)(16)(17)(18) correlate quite well with eq. 9 and fit the expression…”

Section: Chc(r)(cn)oo' > Ch3c(r)(oc(0)ch3)oo' > Ch3-' C(r) (C(o)ochmentioning

confidence: 71%

Absolute Rate Constants for Hydrocarbon Autoxidation. XXII. The Autoxidation of some Vinyl Compounds

Howard¹

1972

Can. J. Chem.

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Absolute propagation and termination rate constants have been determined for the autoxidation of some vinyl compounds at 30' . Rates of propagation depend on the structure of both the peroxy radical and the vinyl compound. The reactivity of peroxy radicals towards addition increases as the electron-withdrawing capacity of the a-substituent increases. Rate constants for addition of I-butylperoxy radicals to vinyl compounds, kt;FO, fit the equationwhere E, is the estimated stabilization energy of the j-peroxyalkyl radical (in kcal/mol) formed in the addition reaction.Les constantes absolues de vitesse de propagation et de terminaison ont kt6 determinees pour l'autoxydation de quelques composes vinyliques a 30' . Les vitesses de propagation dependent a la fois de la structure du radical pkroxy et du compose vinylique. La reactivite des radicaux peroxy pour l'addition croit avec le pouvoir electroattracteur du substituant en a. Les constantes de vitesse de l'addition des radicaux t-butylperoxy aux composes vinyliques, kt;io0, satisfont l'equationod E, est l'energie de stabilisation mesuree du radical 8-peroxyalkyl (en kcal/mol) forme dans la reaction d'addition.

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Reactions of Methyl Radicals with Substrates Acting as Hydrogen Donors and as Methyl Radical Acceptors

Cited by 36 publications

References 1 publication

Chemistry of the tert-butyl radical: polar character, .rho. value for reaction with toluenes, and the effect of radical polarity on the ratio of benzylic hydrogen abstraction to addition to aromatic rings

Chemistry of the tert-butyl radical: polar character, .rho. value for reaction with toluenes, and the effect of radical polarity on the ratio of benzylic hydrogen abstraction to addition to aromatic rings

Byproduct identification in the terephthalic acid production process and possible mechanisms of their formation

Absolute Rate Constants for Hydrocarbon Autoxidation. XXII. The Autoxidation of some Vinyl Compounds

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