ISSN:
1572-901X
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract A detailed investigation of the oxidation of L-ascorbic acid (H2A) by the title complex has been carried out using conventional spectrophotometry at 510 nm, over the ranges: 0.010 ≤ [ascorbate] T ≤ 0.045 mol dm−3, 3.62 ≤ pH ≤ 5.34, and 12.0 ≤ θ ≤ 30.0 °C, 0.50 ≤ I ≤ 1.00 mol dm−3, and at ionic strength 0.60 mol dm−3 (NaClO4). The main reaction products are the bis(pyridine-2,6-dicarboxylate)cobaltate(II) ion and l-dehydroascorbic acid. The reaction rate is dependent on pH and the total ascorbate concentration in a complex manner, i.e., k obs = (k 1 K 1)[ascorbate] T /(K 1 + [H+]). The second order rate constant, k 1 [rate constant for the reaction of the cobalt(III) complex and HA−] at 25.0 °C is 2.31 ± 0.13 mol−1 dm3 s−1. ΔH
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1007046125017