The oxidation of arsenic (III) by chromium (VI) has been studied in pyridine - pyridinium buffers with and without added oxalate ion.
The rate law at pH 4.6 for the reactions without oxalate is best described as
- d[Cr(VI)]/dt = (0.535 [As(III)]² [Cr(VI)])/(1+187 [As(III)])
This is in accord with the general mechanism for chromium (VI) oxidation proposed by Beattie and Haight. The behavior in pyridine - pyridinium buffers is different from that observed in acetic acid acetate buffers of the same pH.
In the presence of oxalate, the observed rate law is
- d[Cr(VI)]/dt = (310 [As(III)] [C₂O₄²⁻] [Cr(VI)])/(1+31.0 [As(III)])
In each case the reaction stoichiometry was found to be 3As(III) + 2Cr(VI) = 3As(V) + 2Cr(III). The role of oxalate was found to be catalytic although it was incorporated in the final Cr(III) product.
Complex kinetic behavior was observed as a function of pH, [AsIII], and buffer composition. / M.S.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/104524 |
| Date | January 1985 |
| Creators | O'Neal, Stephen Vernon |
| Contributors | Chemistry |
| Publisher | Virginia Polytechnic Institute and State University |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Thesis, Text |
| Format | x, 74 leaves, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 12749074 |
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