The vanadate anion in the presence of pyrazine-2-carboxylic acid (PCA) was found to effectively catalyze the oxidation of isopropanol to acetone with hydrogen peroxide. The electronic spectra of solutions and the kinetics of oxidation were studied. The conclusion was drawn that the rate-determining stage of the reaction was the decomposition of the vanadium(V) diperoxo complex with PCA, and the particle that induced the oxidation of isopropanol was the hydroxyl radical. Supposedly, the HO• radical detached a hydrogen atom from isopropanol, and the Me2 C• (OH) radical formed reacted with HOO• to produce acetone and hydrogen peroxide. The electronic spectra of solutions in isopropanol and acetonitrile and the dependences of the initial rates of isopropanol oxidation without a solvent and cyclohexane oxidation in acetonitrile on the initial concentration of hydrogen peroxide were compared. The conclusion was drawn that hydroxyl radicals appeared in the oxidation of alkanes in acetonitrile in the decomposition of the vanadium diperoxo complex rather than the monoperoxo derivative, as was suggested by us earlier.

This mechanism is supported by isotopic and steric effects. Co-catalytic systems were explored for the oxidation of alcohols using sodium bromide or oxoammonium ions with the H202/MTO system. The molecular oxygen binding rate constant for a variety of Co(II)salen derivatives was explored. The rate constant was determined using flash photolysis to dissociate oxygen from the pre-made CO(III)-02· complex. A new twist to the rate constant determination of these reactions was also explored where in flash photolysis severs a cobalt-carbon bond of a Co(Ill)-alkyl complex, producing the CO(III) complex in the presence Of 02 and a radical scavenger.

Catalysis is a very interesting area of chemistry, which is currently developing at a rapid pace. A great deal of effort is being put forth by both industry and academia to make reactions faster and more productive. One method of accomplishing this is by the development of catalysts. Enzymes are an example of catalysts that are able to perform reactions on a very rapid time scale and also very specifically; a goal for every man-made catalyst. A kinetic study can also be carried out for a reaction to gain a better understanding of its mechanism and to determine what type of catalyst would assist the reaction. Kinetic studies can also help determine other factors, such as the shelf life of a chemical, or the optimum temperature for an industrial scale reaction. An area of catalysis being studied at this time is that of oxygenations. Life on this earth depends on the kinetic barriers for oxygen in its various forms. If it were not for these barriers, molecular oxygen, water, and the oxygenated materials in the land would be in a constant equilibrium. These same barriers must be overcome when performing oxygenation reactions on the laboratory or industrial scale. By performing kinetic studies and developing catalysts for these reactions, a large number of reactions can be made more economical, while making less unwanted byproducts. For this dissertation the activation by transition metal complexes of hydrogen peroxide or molecular oxygen coordination will be discussed.

Keywords. thiol oxidation, cysteine, hydrogen peroxide, nucleophilic substitution, amorphous solid

Allylic alcohols were oxidized using hydrogen peroxide as an oxygen source and methyltrioxorhenium (MTO) as catalyst. Hydrogen peroxide and MTO react to form 1:1 and 2:1 rhenium peroxides, denoted as A and B, respectively. The bisperoxide species, B was the reactive form of the catalyst. The rate constants for the oxidation of the allylic alcohols were evaluated using pseudo-first-order techniques and were slower than the corresponding alkenes. An unexpected dependence of the rate constant on [H202] was found for fast-reacting substrates. A mechanism featuring H-bonding of the allylic alcohol with a peroxidic oxygen of the catalyst is proposed. Kinetic measurements with added pyridine N-oxide showed that the rate constants initially decrease with increasing pyridine N-oxide concentration, reach a minimum, and then increase, finally surpassing that of the experiment without pyridine N-oxide.