Trace metal-ion catalysis: kinetics and mechanism of oxidation of l-ascorbic acid by chromium(VI) in phosphate buffers |
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Authors: | Amita Agrawal Indu Rao Prem D Sharma |
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Institution: | (1) Department of Chemistry, University of Rajasthan, 302 004 Jaipur, India |
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Abstract: | Summary The kinetics of oxidation of l-ascorbic acid (H2A) by CrVI with and without added CuII conforms to the stoichiometry represented by the equation: 2CrVI + 3H2A 2CrIII + 3A + 6H+ where A is dehydroascorbic acid. The mode of the electron transfer from H2A to CrVI is suggested to involve oxidative decomposition of an intermediate complex. Catalysis by CuII is indicated via complexation of the catalyst and substrate. The inhibitory effects of Cl–, NO
f3
p–
and SO
f4
p2–
ions indirectly support complexation between CrVI and H2A. |
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Keywords: | |
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