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Kinetics and mechanism of the addition of trichloromethyl radicals to chloroethylenes. The addition to CIS ‐C 2 Cl 2 H 2 , trans ‐C 2 Cl 2 H 2 , and C 2 Cl 3 H
Author(s) -
Horowitz A.,
Baruch G.
Publication year - 1980
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550121107
Subject(s) - chemistry , radical , reactivity (psychology) , cyclohexane , electrophile , adduct , arrhenius equation , medicinal chemistry , kinetics , addition reaction , photochemistry , activation energy , organic chemistry , catalysis , medicine , physics , pathology , quantum mechanics , alternative medicine
The addition reactions of CCl 3 radicals with cis ‐C 2 Cl 2 H 2 , trans ‐C 2 Cl 2 H 2 , and C 2 Cl 3 H in liquid cyclohexane–CCl 4 mixtures were studied between 323 and 448 K. The Arrhenius parameters of these reactions were competitively determined versus H‐atom transfer from cyclohexane and addition to C 2 Cl 4 . The present data and the data obtained in previous liquid and gas phase studies show that the reactivities displayed in addition reactions of different radicals with chloroethylenes reflect primarily variations in activation energies rather than in A factors. The activation energies for the addition of CCl 3 , CF 3 , and CH 3 radicals to chloroethylenes appear, to a large extent, to be determinedby the stability of the adduct radicals. Comparison of the reactivity trends in the addition reactions of chloro‐ and fluoro‐substitutedethylenes indicates that these two electron‐withdrawing substituentshave a converse effect on the reactivity of electrophilic radicals. This behavior is ascribed to the strong mesomeric effect of vinylic chlorosubstituents.