Kinetics and mechanism of oxidation of D-glucose by chromium(VI) in perchloric acid

The oxidation of D-glucose with Cr(VI) in aqueous perchloric acid proceeds via formation of a 1:1 complex which is considered to be chromium (VI) bond ed to anomeric-OH group. The complex is formed within the time of mixing an d remains stable for greater than or equal to 24 h in the absence of perchl oric acid. The reaction products are D-1,4-glucolactone and Cr(III). Format ion of CO2 has not been observed during the course of reaction under the ex perimental kinetic conditions. The reaction rate increases with [HClO4] and no acid-independent path has been observed. Manganese(II) inhibits the rea ction rate and the order is found to be zero in [manganese(II)]. The kineti cs of electron-transfer reactions to yield Cr(III) have been investigated s pectrophotometrically and, on the basis of experimental data, mechanisms ar e presented and discussed.