Title

Kinetics and Mechanism of Chromate Reduction with Hydrogen Peroxide in Base

ACS Citation

Vander Griend, D. A.; Golden, J. S.; Arrington, C. A. Kinetics and Mechanism of Chromate Reduction with Hydrogen Peroxide in Base. Inorg. Chem. 2002, 41, 7042-7048.

Abstract

CrVIO4]2- is reduced to CrV(O2)4]3- by hydrogen peroxide in strongly basic media where the acid dissociation of H2O2 (pKa = 11.65) is appreciable. The reaction is first order in chromium(VI) and inhibited by hydroxide. The hydrogen peroxide dependence is defined by the form of the effective pseudo-first-order rate constant:? keff = H2O2]3/(K1 + K2H2O2] + K3HO2-]) with K1 = 175(43) s·M3, K2 = 403(18) s·M2, and K3 = 1422(34) s·M2. Hydrogen peroxide anion initially attacks chromate, and subsequent equilibrium steps that exchange oxo groups for three peroxo groups precede a rate-determining, one-electron, intramolecular reduction step. CrVIO4]2- is reduced to CrV(O2)4]3- by hydrogen peroxide in strongly basic media where the acid dissociation of H2O2 (pKa = 11.65) is appreciable. The reaction is first order in chromium(VI) and inhibited by hydroxide. The hydrogen peroxide dependence is defined by the form of the effective pseudo-first-order rate constant:? keff = H2O2]3/(K1 + K2H2O2] + K3HO2-]) with K1 = 175(43) s·M3, K2 = 403(18) s·M2, and K3 = 1422(34) s·M2. Hydrogen peroxide anion initially attacks chromate, and subsequent equilibrium steps that exchange oxo groups for three peroxo groups precede a rate-determining, one-electron, intramolecular reduction step.

Source Name

Inorganic Chemistry

Publication Date

1-1-2002

Volume

41

Issue

26

Page(s)

12249-12257

Document Type

Citation

Citation Type

Article