A kinetic study of the reactions of sulfate and dihydrogen phosphate radicals with epicatechin,epicatechingallate, and epigalocatechingallate |
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| Authors: | Laura S Villata Mónica C Gonzalez Daniel O Mártire |
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| Institution: | Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4, 1900 La Plata, Argentina |
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| Abstract: | The bimolecular rate constants for the reactions of sulfate radicals with epicatechin (EC), epicatechingallate (ECG), and epigallocatechingallate (EGCG) were found to be (1.46 ± 0.06) × 109, (1.20 ± 0.08) × 109, and (1.04 ± 0.07) × 109, respectively. The activation energy EA = 9 ± 3 kJ mol?1] and preexponential factor A = (4.8 ± 0.6) × 1010] for the reaction of EC with the sulfate radical were measured in the temperature range 288–303 K. The phenoxyl radicals of EC (λmax = 310 nm) were obtained both by the reaction of this flavonoid with the sulfate radicals and by photoionization. The measured bimolecular rate constants for the reactions of the dihydrogen phosphate radicals with EC, ECG, and EGCG were (7.8 ± 0.9) × 108, (8.5 ± 0.4) × 108, and (6.8 ± 0.4) × 108, respectively. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 391–396, 2010 |
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