Kinetic Isotope Effect for Hydrogen Abstraction by <sup>•</sup>OH Radicals from Normal and Carbon-Deuterated Ethyl Alcohol and Methylamine in Aqueous Solutions
作者:Marija Bonifačić、David A. Armstrong、Igor Štefanić、Klaus-Dieter Asmus
DOI:10.1021/jp027790e
日期:2003.7.1
Selective H/D kineticisotopeeffects (KIEs) have been determined for the various routes by which •OH radicals react with ethanol (CH3CH2OH and CD3CD2OH) and methylamine (CH3NH2 and CD3NH2) in H2O solutions. The KIEs have been evaluated from overall rate constants and the yields in which the individual primary radicals were generated in the •OH reaction with these compounds. The analytical method applied
Free energy hydride affinities of quinones in dimethyl sulfoxide solution
作者:Jinpei Cheng、Kishan L. Handoo、Jieyou Xue、Vernon D. Parker
DOI:10.1021/jo00071a011
日期:1993.9
Free energy hydride affinities in solution defined by reaction i [(i) Q(s) + H-s reversible (QH-)s, DELTAG(hydride)(Q)s] were evaluated for a number of quinones (Q) in dimethyl sulfoxide solution using reaction ii [(ii) -DELTAG(hydride)(Q)s = 2.303RTpK(a)(QH-)s + FDELTAE-degrees(NHE)[(Q.-/Q2-)s + (Q/Q.-)s] + C] derived from a thermochemical cycle. The constant C corresponds to -FE-degrees(NHE)[(H+/H.)s + (H./H-)s] which is equal to 69.9 kcal/mol in dimethyl sulfoxide. The pK(a) of hydroquinone monoanions (QH-) were determined by the overlapping indicator method. Reversible electrode potentials for both the first and second charge transfers to Q were determined by cyclic voltammetry. Values of DELTAG(hydride)(Q)DMSO ranging from -58 to -101 kcal/mol were observed. Hydride affinities of substituted benzoquinones (BQ) were found to be linearly correlated with the corresponding electron affinities in solution. Equilibrium constants for the reactions of BQ with the NADH model compound 10-methylacridan were estimated, and the thermochemical results are discussed in terms of the one- and the two-step mechanisms of hydride-transfer reactions.
Substituent effects on rates of one-electron oxidation of phenols by the radicals chlorine dioxide, nitrogen dioxide, and trioxosulfate(1-)
作者:Zeev B. Alfassi、Robert E. Huie、P. Neta
DOI:10.1021/j100408a063
日期:1986.8
Parker, Vernon D.; Cheng, Jin-Pei; Handoo, Kishan L., Acta Chemica Scandinavica, 1993, vol. 47, # 11, p. 1144 - 1145
作者:Parker, Vernon D.、Cheng, Jin-Pei、Handoo, Kishan L.