Kinetic studies on the oxidation of ascorbic acid by technetium(VII)

Abstract

The pertechnetate ion oxidizes ascorbic acid in strong acid medium to form red species. A reaction mechanism has been developed which correctly predicts all the experimental facts. The results obtained support the postulate according to which the red species corresponds to a complex formed between Tc(V) and dehydroascorbic acid. The rate constants and Arrhenius parameters have been investigated.

Impairment of ascorbic acid’s anti-oxidant properties in confined media: Inter and intramolecular reactions with air and vanadate at acidic pH

“…The reaction between V(V) and ascorbic acid is pH dependent [85][86][87]. The initial study by Kustin and Toppen of the V(V)-ascorbic acid system was carried out below pH 1 [15].…”

Reduction of Vanadium(V) by l-Ascorbic Acid at Low and Neutral pH: Kinetic, Mechanistic, and Spectroscopic Characterization

“…One successful study was the reaction of pertechnetate with ascorbic acid, which after reduction was shown to produce what is believed to be a technetium(V) dehydroascorbic acid complex. 21 In 1973, Kustin and Toppen 14 reported the first kinetic study of the reduction of vanadium(V) with ascorbic acid. At low pH, vanadium(V) exists as cis-dioxovanadium(V), VO 2 + ; however, as the pH is increased, the most prevalent forms are vanadate, H 2 VO 4 -, or decavanadate, H 3 V 10 O 28 3-.…”

“…Few studies have focused on the spectroscopic characterization of the complexes that form between the oxidant and ascorbate or its corresponding oxidation product. One successful study was the reaction of pertechnetate with ascorbic acid, which after reduction was shown to produce what is believed to be a technetium(V) dehydroascorbic acid complex …”

The different kinetic and mechanistic behaviors of molybdenum and tungsten in the reduction of tris(benzene‐1,2‐dithiolato)Mo(VI) and W(VI) complexes by ascorbic acid in aqueous media

“…The oxidation of ascorbic acid by labile substitution and aquo transition-metal complexes has been widely studied during the past few decades [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Usually, these oxidations have an inner-sphere nature due to the fact that the cations coordinate one of the hydroxyl groups of ascorbic acid, inducing a mono-electronic rate-limiting electron transfer toward the metallic center.…”