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.

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A flow solid/liquid intermolecular transfer (SLIT) ¹H dynamic nuclear polarization (DNP) experiment is described. The SLIT ¹H DNP results are reported for the case of flowing benzene over silica gel surfaces prepared with stable immobilized nitroxide and phenoxy spin labels. The advantages of the flow SLIT DNP experiment in comparison with the recently reported flow liquid/liquid intermolecular transfer (LLIT) ¹H DNP experiment are discussed. The results suggest that the flow SLIT DNP experiment provides a new method for monitoring liquid/surface intermolecular interactions, since the reporter group (flowing benzene) reflects properties of the surface. Potential applications such as: 1) observation of enhanced NMR signals without detrimental line broadening due to the presence of stable free radicals in the NMR detection region, and 2) independent optimization of the "EPR" and "NMR" portions of the DNP experiment, are discussed. The thrust of this thesis was twofold: 1) to synthesize immobilized free radical systems appropriate for the SLIT DNP measurements, and 2) to establish the factors influencing DNP mechanism(s) for these systems. The resulting ¹H DNP line shapes imply that both Overhauser effect and solid- state effect are effective mechanisms for the DNP enhancements. The results suggest that the relatively low magnitude of the enhancements can be attributed to the longer molecular correlation times of the solid/liquid systems studied. Also, the EPR spectra and the corresponding number of unpaired spins were measured for these immobilized systems. / M.S.

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The following investigation was undertaken to find a method for the oxidative cleavage of the double bond, using oleic acid. The primary purpose of this investigation was to find a cheap method of splitting the double bond in oleic acid and obtaining the saturated fatty acids formed therefrom. The procedure used in the attempt to accomplish these results was the auto-oxidation of the oleic acid. This was carried out with and without a catalyst, and also, in the presence of a chemical oxidizing agent. The results from the runs, with and without a catalyst, were poor in that no split of the double bond took place, but in most cases more favorable results were obtained in the presence of catalysts. The results were positive in the one case in which the chemical oxidizing agent was used with the catalyst. This run gave a split of the double bond and warrants further investigation. 1. No split of the double linkage in oleic acid was obtained from its autoxidation over a period of four hundred twenty-five hours, with or without a catalyst. 2. The ozonide of oleic acid was not formed, although the presence of peroxide oxygen was detected. 3. Iron oxide (Fe₃O₄) was a positive autoxidation catalyst, whereas, vanadium pentoxide was a negative catalyst. 4. Cleavage of the double linkage was obtained when concentrated nitric acid was used as the oxidizing agent in presence of vanadium pentoxide as the catalyst. The split was very slight, as only 0.4 gram of suberic acid was isolated from 89.5 grams of oleic acid. / M.S.

The purpose of this investigation may be summarized as follows: (1) Search for new colorimetric organic reagents. (2) Discovery of any organic compound that shows properties of an indicator. (3) Discovery of any organic compound that shows properties of an oxidizing or reducing agent. (4) Discovery of any other information that may be of analytical importance. / M.S.

On the basis of the present data it would seem that there is no marked relationship between the surface tension and the degree of polymerization of nitrocellulose solutions of normal butyl acetate as determined by the Du Nouy method. It should be noted that no great precision is present in the recorded data. A slight change in surface tension due to a difference in the degree of polymerization could easily be more than offset by errors in measurement. The solutions become much more viscous with increased concentration. This limited the range over which the surface tension could be measured with any degree of accuracy. For with highly viscous solutions the ring would be pulled slowly from the surface making it extremely difficult to determine the exact force required for the break. A second effect was that with increasing concentration a film of the solution adhered across the ring. The data indicates that there is no great change in the surface tension with varying concentration within the range studied. / M.S.