Radicals and scavengers. 7. Diffusion controlled scavenging of phenyl radicals and absolute rate constants of several phenyl radical reactions

KRYGER, R. G.; Lorand, John P.; STEVENS, N. R.; Herron, Nelson R.

doi:10.1021/ja00465a030

Cited by 104 publications

(46 citation statements)

References 5 publications

(6 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Phenylazotriphenylmethane (PAT) was prepared as described previously. [21] 2,4,6-Trimethylbenzoyl diphenylphosphonyloxide (TMDPO; BASF) was recrystallized twice from ethanol/diethyl ether.…”

Section: Methodsmentioning

confidence: 99%

The Effect of the Heteroatom Moiety of Allylic Salts on the Addition Fragmentation Initiation of Cationic Polymerization

Önen¹,

Yaǧcı²

2001

Macromol. Chem. Phys.

View full text Add to dashboard Cite

Thermally and photoinduced cationic polymerizations of cyclohexene oxide (CHO) initiated by allylthiophenium, allylpyridinium, allylalkoxypyridinium and allylphosphonium salts with non‐nucleophilic counter anion hexafluoroantimonate and with an ethoxy carbonyl substituent at the allylic moiety were studied. The catalytic activities in the polymerization were examined and compared to those measured in both the absence and presence of added radical initiators.

show abstract

Section: Methodsmentioning

confidence: 99%

The Effect of the Heteroatom Moiety of Allylic Salts on the Addition Fragmentation Initiation of Cationic Polymerization

Önen¹,

Yaǧcı²

2001

Macromol. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…A recent study (1) gave k&TC = 3.4 X lo5 M-' s -' for the reaction of the methyl radical with BrCC13 in the gas phase. Much larger values were reported recently for corresponding reactions of phenyl (2) and of cyclopropyl radicals (3) in solution, rate constants having values 1.7 x lo9 (45°C) and (2.8-3.7) x lo9 (25°C) M-Is-', respectively. In abstraction of C1 from CC14 at about 298 K, the phenyl radical (2, 4) reacts 6.5 X lo2, 1.3 x lo2, and 1.4 x lo3 times faster than the neophyl radical (5), the butyl radical (6), and the 5-hexenyl radical (7) respectively.2 Cyclopropyl radical is also more reactive toward CC14 (3a) than the above mentioned primary radicals; corresponding rate factors '~u t h o r to whom correspondence may be addressed.…”

Section: Introductionmentioning

confidence: 62%

“…[2], the symbols [5]- [9] represent the relative yields, the fact that Ph and cpm are, within experimental error, equally reactive toward BrCC13. A similar argument can be used to [BrCC13] is the initial concentration of that reagent, and k, is the accommodate the apparently higher reactivity (kby = 2.8 x rate constant for ring opening of cyclopropylmethyl, calculated lo9 M-' s-') at 25°C of cyclopropyl radicals (cp) (3b) relative from the equation (10) log ( k l l s ' ) = 13.9-7.618 where 0 = to that of phenyl radicals, toward BrCC13.…”

Section: Rate Corlstarltsmentioning

confidence: 99%

Rate constants for abstraction of bromine from bromotrichloromethane by butyl, cyclopropylmethyl, and phenyl radicals in solution

Mathew¹,

Warkentin²

1988

Can. J. Chem.

View full text Add to dashboard Cite

LUKOSE MATHEW and JOHN WARKENTIN. Can. J. Chem. 66, l l (1988).The radical chain decomposition of cyclopropylmethyl (I-hydroxy-1-mcthylethy1)-diazcnc ((CH3)2C(OH)N=NCHI--<1 1) at 253-341 K in hexafluorobenzene or in dichloromethane solution containing brornotrichloromethane affords cyclopropylmethyl bromide, 4-bromo-I-butene, I-bromo-5,5,5-trichloro-2-pentene, and 3,5-dibromo-I, I, I-trichloropcntane from the cyclopropylmethyl portion of 1. Other major products are nitrogen, acetone, and chloroform. The rate constant for formation of cyclopropylmethyl bromide by attack of cyclopropylmethyl free radicals from 1 at bromine of BrCCI, (kyy) was calculated from the product composition using the known rate constant for rearrangement of cyclopropylmethyl radicals to 3-buten-I-yl radicals. At 25"C, kTF = 6.5 X lo8 M-I s-I and the temperature dependence is given by log (ksm/M-I s-) = ( 10.6 5 0.3) -(2.4 C 0.4)/0, where 0 = 2.3R~kcal/mol-l. Non-chain decompositionof (CH3),C(OH)N=N-R(2, R = Bu, and3, R = Ph) in the presence of excess 1 ,I ,3,3-tetramethylisoindolin-2-yloxyl (4) and bromotrichloromethane afforded BuBr and PhBr, respectively, in yields determined by the relative concentrations of 4 and BrCCI3. Rate constants for coupling ( k c ) of Bu. and Ph. with 4 were assumed to be proportional to rate constants for diffusion controlled reactions, kd, which were estimated from measured viscosities. Values of k ! : and k; : , calculated from kc and product yields for reactions at 80°C, are 0.26 X lo9 and 1.55 X lo9 M-' s-l, respectively. The relative radical reactivities toward BrCC13 at 80°C are Ph, 6; cpm, 5; Bu, 1.LUKOSE MATHEW et JOHN WARKENTIN. Can. J. Chem. 66, 1 1 (1988).La dCcomposition radicalaire en chaine du cyclopropylmCthy1 (hydroxy-l methyl-1 Cthyl) diazkne ((CH3)2C(OH)N= NCH2CH(CH2),, I), a des tempkratures allant de 253 2 341 K, dans des solutions d'hexafluorobenzkne ou de dichloromCthane contenant du bromotrichloromtthane, conduit au bromure de cyclopropylmCthyle, au bromo-4 butkne-I, au bromo-l trichloro-5,5,5 pentkne-2 et au dibromo-3,5 trichloro-l ,I , l pentane qui dtrivent tous de la portion cyclopropylmCthyle du compost 1. Les autres produits importants sont l'azote, I'acCtone et le chloroforme. On a calculi2 la constante de vitesse pour la formation du bromure de cyclopropylmtthyle par attaque des radicaux libres cyclopropylmCthyles, provenant du compost 1, au niveau du brome du BrCC13 (kTF); pour ce faire, on afait appel a lacomposition des produits-et on a utilisC la constante de vitesse connue pour la transposition des radicaux cyclopropylmCthyles en radicaux butkne-3 yles. A 25"C, kgm = 6.5 X lo8 M-' s-I et lavariation avec la tempkratureest donnte parl'iquation suivante : log (kxm/M-I s-I) = (10,6 C 0,3) -(2,4 -C 0,4)/0, dans laquelle 0 = 2,3R~kcal/rnol-'. Les dCcompositions des composCs (CH3)?C(OH)N=N-R (2, R = Bu, et 3, R = Ph) par un processus qui n'implique pas de chaines, en presence d'un excks de tCtramCthyl-1,1,3,3 isoindolinyl-2 oxyl (4) et de bromotrichloromCthane, fournissent respect...

show abstract

“…Reaction (1) appears to be very fast and selective since neither hydrogen abstraction from the solvent nor phenylation of quinoline were observed. The absolute rate constants of these latter reactions are in the range 10 5 -10 6 M À1 s À1 [2,6,7], so that the rate constant >10 7 M À1 s À1 can be evaluated for reaction (1). Such a high rate is mainly justified by enthalpic factors, since the bond dissociation enthalpy (BDE) is higher for the Ph-I bond compared to the R f -I bond.…”

Section: Resultsmentioning

confidence: 99%

Enthalpic and polar effects in the reactions of perfluoroalkyl radicals

Antonietti

Minisci

Punta

et al. 2004

Journal of Fluorine Chemistry

View full text Add to dashboard Cite

Radicals and scavengers. 7. Diffusion controlled scavenging of phenyl radicals and absolute rate constants of several phenyl radical reactions

Cited by 104 publications

References 5 publications

The Effect of the Heteroatom Moiety of Allylic Salts on the Addition Fragmentation Initiation of Cationic Polymerization

The Effect of the Heteroatom Moiety of Allylic Salts on the Addition Fragmentation Initiation of Cationic Polymerization

Rate constants for abstraction of bromine from bromotrichloromethane by butyl, cyclopropylmethyl, and phenyl radicals in solution

Enthalpic and polar effects in the reactions of perfluoroalkyl radicals

Contact Info

Product

Resources

About