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An EMS study of the adsorbable and electrooxidizable impurities in our electrochemical system was undertaken. The source of most of the impurities was found and corrected. The adsorbtion and oxidative desorbtion of methylcyclohexane and isobutane was studied. Steady state and time dependent results are presented. A new digital data acquisition and experimental control system was developed and interfaced to the EMS system. This system made possible the acquisition of much more useful data from a single experiment rather than depending upon very high reproducibility between experiments., See also report dated Dec 73, AD-A009 017.

Elucidation of the mechanism of propane electrooxidation on platinum is complicated by the presence of several partially oxidized carbonaceous adsorbates. In this work techniques of 'Electrochemical Mass Spectrometry' (EMS) have been developed and applied to simplify analytical characterization of species present at the propane anode. EMS is based on interfacing a non-wetting porous electrode to the inlet system of a mass spectrometer. The preparation of a suitable porous electrode is described. Transport across the gas-liquid interface is characterized using a rotating porous disk. A diffusion model is developed for the porous electrode. Steady state and nonsteady state collection phenomena are investigated. A novel technique for the determination of diffusion coefficients is presented. Labelled carbon studies were carried out using propane-2-13C. Observations on the open circuit behavior of the propane anode are included., See also report dated Dec 73, AD/A-006 550.

The properties of propane and propane-2-C13 adsorbates formed at 0.25 V vs. the polarized hydrogen electrode (0.274 vs. RHE) were examined using electrochemical mass spectrometry (EMS). Experimental results indicate the presence of adsorbable organic impurities which compete with propane for adsorption sites. Based on the time dependence of inhibition of hydrogen adsorption, the impurity level appears comparable to that of earlier workers. All of the C(13)C2H8 adsorbed can be accounted for on the basis of products desorbed at either 0.05 V (propane and ethane) or at large anodic potentials (carbon dioxide). The results support the view that (1) propane formed on cathodic desorption arises from the original carbon skeleton of the absorbable propane and (2) methane produced at 0.25 V is produced with equal probability from all carbons in the original propane. (Modified author abstract), See also report dated Jun 72, AD-755 254.

Electrochemical Mass Spectrometry was used to determine the absolute amounts of desorbable C-1, C-2 and C-3 species from propane adsorbed on a platinum electrode at 0.3V. The construction of porous electrodes as well as a brief presentation of their theory and application is given. A method for synthesizing propane-2-(13)C from acetic acid-1-(13)C is presented. (Author)

A reproducible procedure of seeded growth in stable supersaturated solutions was successfully applied to the growth and dissolution of dicalcium phosphate (DCP) and to the growth of synthetic hydroxyapatite (HAP) crystals. The influence of a number of added substances, known to be effective inhibitors of caries production, upon these processes was investigated both chemically and microscopically. (Author)

Iminium cations can be generated by ionization of oxime polyphosphates of rigid ketones incapable of rearrangement and fragmentation. This report summarizes a research effort to determine whether singlet or triplet ions are involved as intermediates in appropriate compounds when they react to produce C-H insertion and non-stereospecific rearrangement products. Another goal of this research was to find substrates where remote intramolecular nucleophilic attack at nitrogen would supersede the conventional Beckmann isomerization. (Author)

A brief review of the author's research is presented. Part of the investigation studied the chemical response to ultraviolet radiation of several small ring heterocyclic systems. The phototransformations of beta, gamma-epoxy ketones, dibenzoylstilbene episulfides, arylaroylazetidines, cyclopentyl phenyl ketone, and alpha-diazoacetophenone were examined in mechanistic detail. Photosensitization, quenching, and emission studies were performed in order to describe the excited states involved in these photoreactions as well as to provide for a better understanding of the mechanism of these transformations. (Author)