Absolute rate constants for the reactions of primary alkyl radicals with aromatic amines
- Univ. of St. Andrews, Fife (United Kingdom)
Hydrogen abstraction from diarylamines (4-X-C{sub 6}H{sub 4}) [X = H, CH{sub 3}, C{sub 8}H{sub 17}, CH{sub 3}O, and Br] by the 2-methyl-2-phenylpropyl radical in n-dodecane solution was investigated by thermolysis of 3-methyl-3-phenylbutanoyl peroxide in the presence of various concentrations of the amines. The reaction is a non-chain process in which the 2-methyl-2-phenylpropyl radical and its rearrangement product, the 2-benzylpropan-2-yl radical, abstract hydrogen from both the solvent and the amine. Cross-disproportionation reactions of the rearranged radical led to the formation of significant amounts of {beta}, {beta}-dimethylstyrene. Rate constants for hydrogen abstraction by the unrearranged, primary alkyl radical form n-dodecane (k{sup 373K}= 3.5 x 10{sup 3} M{sup {minus}1} s{sup {minus}1}), diphenylamine (k{sup 373K} = 1.3 x 10{sup 6} M{sup {minus}1} s{sup {minus}1}), and the substituted diarylamines were determined from the product yields and the known rate constant for the radical rearrangement. From kinetic experiments with N-deuteriodiphenylamine and deuterium kinetic isotope effect, k{sub NH}/k{sub ND}, was found to be 2.3 at 373 K. 28 refs., 1 fig., 1 tab.
- OSTI ID:
- 494234
- Journal Information:
- Journal of Organic Chemistry, Journal Name: Journal of Organic Chemistry Journal Issue: 11 Vol. 61; ISSN 0022-3263; ISSN JOCEAH
- Country of Publication:
- United States
- Language:
- English
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