ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The autoxidation of CuI in aqueous MeCN has been studied using a Clark oxygen electrode in the presence and absence of Cu11. The reaction is inhibited by Cu11 in the pH range of 0.5 to 5.0, reaching a lower limiting value at the highest concentrations. The reaction order changes from 1 to 2 with respect to CuI under the influence of Cu2+ ion. Detailed kinetics analysis of a total of 275 measurements has shown that an unstable primary adduct CuO+2 decomoses to give .O2- or HO2., depnding on pH, and also reacts directly with a second Cu+ ion, avoiding one-electrton reduction of O2 by this path. Reaction of HO2. is faster with CuI than with Cu11 by a factor of 20, and single-electron transfer within CuO+2 to Cu2+ and .O2- predominates over reaction with a second copper ion for [CuItot] 〈 2. 10-3M in the absence of Cu2+. The most likely value for the reaction of .O2- with CuI is 5.3 · 108 M-1S-1, but even this high rate constant is at the limit of significance. All secondary reactions followinfg the initial formation of CuO+2 are shown to be very fast, a fact that should be properly considered in the discussion of mechanisms of copper-catalyzed oxidations and oxygenations.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19910740808
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