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Title: Reduction of dimensionality in radical decay kinetics induced by micellar systems. [Electron pulse radiolysis; cetyltrimethylammonium bromide; examination and separation of bulk vs surface diffusion]

Journal Article · · J. Am. Chem. Soc.; (United States)
DOI:https://doi.org/10.1021/ja00427a044· OSTI ID:7185322

The dismutation reaction of Br/sub 2//sup -/ ion radicals in aqueous solution was studied in the presence of micellar cetyltrimethylammonium bromide (CTAB) by pulse radiolysis technique. Two kinetic processes involving the Br/sub 2//sup -/ radicals were identified: two-dimensional intramicellar surface diffusion and three-dimensional intermicellar (or solution bulk type) diffusion with respective rate constants of 2.1 x 10/sup 6/ s/sup -1/ and 1.46 x 10/sup 9/ M/sup -1/ s/sup -1/. The CTAB/Br/sub 2//sup -/ system represents the first example in which two kinetic components of a diffusion-controlled reaction differing in dimensionality of reaction space can be distinguished. Reduction of dimensionality dramatically increases the probability of reaction. Random-walk theory for two- and three-dimensional lattices with traps is invoked to explain these results.

Research Organization:
Univ. of Notre Dame, IN
OSTI ID:
7185322
Journal Information:
J. Am. Chem. Soc.; (United States), Vol. 98:11
Country of Publication:
United States
Language:
English