PART I: THE OXIDATION OF PROPANE AT A CATALYST-COATED ION-EXCHANGE MEMBRANE SOLVATED WITH TRIFLUOROMETHANE SULFONIC ACID MONOHYDRATE. PART II: THE USE OF LEAD AS AN ELECTRODE MATERIAL FOR ANALYTICAL PURPOSES. PART III: THE EFFECT OF BENZIL RADICAL ANION INTERMEDIATES ON THE ELECTROREDUCTION OF BENZIL.

摘要

In Part I, a study of propane electrooxidation on a platinum-coated ion-exchange membrane was conducted in both 85% phosphoric acid and trifluoromethanesulfonic acid monhydrate (TFMSA). The phosphoric acid system's propane electrooxidation currents were characterized with respect to temperature, propane flow rate and oxidation potential. The propane electrooxidation currents of the TFMSA system were determined and compared to the phosphoric acid system.; Steady-state current measurements were made for hydrogen oxidation in both solvents.; Two problems inherent in the TFMSA system were uncovered during these experiments. The conductance of the TFMSA solvent was about one-tenth of the conductance of the phosphoric acid solvent and platinum, the electrocatalyst for propane electrooxidation was found to dissolve under conditions that may occur in a propane fuel cell.; In Part II, the possibility of using lead as an electrode material for analytical purposes was examined. The hydrogen overvoltage characteristics for lead were studied and found to be similar to the hydrogen overvoltage characteristics of mercury.; Several model compounds were studied using the lead electrode. Cadmium and thallous cations both gave the expected current-potential responses. The diffusion coefficient of thallous in 1.0 M H(,2)SO(,4) at 25(DEGREES)C was determined. While 1.08 (mu)M thallous could not be detected using the conventional rotating disk technique, a well defined reduction wave using the modulation technique was recorded.; P-nitroaniline was shown to be reducible at both the lead and gold RDE's. The reduction appears to be a diffusion controlled process and a limit of detection was calculated.; In Part III, the reduction of benzil was studied using lead and gold RDE's. First, the products of the electron transfer step were shown to be the same at the solid electrodes as those at the DME. The reactins that followed were also shown to be the same at these electrodes.; It was determined that radical anions were produced in relatively large amounts by the redox reaction between benzil and stilbenediolate. Both cis and trans conformations of the radical are present in alkaline aqueous-ethanol solutions. It also appears that the radicals are not oxidized or reduced at gold and lead electrodes.