The subject of this thesis was chosen originally as a result of a suggestion made by a manufacturer of lactic acid. Lactic acid is made by a fermentation process from molasses and the acid is extracted from the fermentation liquors as calcium lactate. The conversion of the calcium lactate back to lactic acid is a tedious process from an industrial point of view. It was therefore suggested that the conversion may be more easily accomplished by electrolysis. The first experimental work was conducted with this object in view, but it soon became apparent that it was unlikely that lactic acid could be produced in suitable quantities for industrial purposes by this means. There was no reference in the literature to the electrolysis of calcium lactate, and little reference to the electrolysis of lactates in general, and what there was appeared to be conflicting, so it was decided to continue the investigation into the subject in order to determine what are the products of the anodic oxidation of calcium lactate. Intro., p.1.

The effect of stress on the electrode potential of copper in aerated cupric sulphate and in aerated cupric chloride solutions was studied. The influence of the variables time, temperature, concentration, magnitude of stress, mechanical condition of the metal, and pH was considered. The potential difference between two size #22B&S copper wires was continuously recorded on a type G speedomax automatic recorder. Weights were added to one of the wires and the change in the potential difference between the two wires from the pre-stress potential difference value was taken as the strain potential. At least six runs, using fresh pairs of wire for each run, were carried out to illustrate each specific point and to show the results have statistical significance and are reproducible. The following results were obtained: (A) Electronegative strain potentials have been obtained for copper metal in copper sulfate solution; these changes achieve a maximum at the instants of stressing and then decay with time. The magnitude of the electronegative strain potential for a given stress increased exponentially with the absolute temperature and decreased significantly for concentration changes from 0.0005 N to 0.500 N. (B) Experimental evidences were obtained to support the postulate that strain potentials of copper metal in copper sulfate solution and their time dependence parallel film rupture and repair. (C) Both electronegative and electropositive strain.potentials were obtained with size #22B&S soft copper wire in cupric chloride solution; the sign of the strain potential was negative for a concentration of 0.500 N and the sign of the strain potential was positive for concentrations of 0.100, 0.050, and 0.005. The magnitude of the strain potential did not vary with concentration as for the case of copper wire in copper sulfate solution. The electronegative change, obtained in 0.500 N cupric chloride lasted for less than three seconds whereupon the change in the potential difference between the two wires shifted rapidly to a positive value. An attempt was made to explain these results on the basis of the stability of Cu₂O and CuCl films using potential-pH diagrams. The magnitude of the strain potential for a given stress was found to vary exponentially with the absolute temperature between the range 298°K to 338°K. / Science, Faculty of / Chemistry, Department of / Graduate

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references.

published_or_final_version / Chemistry / Master / Master of Philosophy

Thesis (Ph.D.)--Murdoch University, 2006. / Thesis submitted to the Division of Science and Engineering. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1982. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 320-333).

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 163-172).

Thesis (M.S.)--Northern Michigan University, 2007. / Includes bibliographical references (leaves 82-83).

The oxidation of artificial cuprous sulphide electrodes (Cu/S ratio = 1.93) was studied in acidified copper sulphate solutions in the temperature range 20 to 35° C. Rest potential measurements gave V° = 0.490 volts for the electrode or half cell potential. This is within the limits of accuracy of V° for: Cu₂S —CuS + Cu⁺⁺ + 2e V° = 0.535 + 0.13 volts The discrepancy was thought to be related to the large Cu deficien in the sulphide. In solutions with pH>4, the rest potential measurements were consistent with the following reaction: Cu₂S + 2H₂0 —CuS + Cu(OH)₂ + 2H⁺ + 2e Polarization measurements at low overpotential gave values for the following kinetic parameters: β, the symmetry factor = 1/2 λ, the number of electrons involved in each act of the rate determining step = 2 i₀, the exchange current ≈ 2 x 10-⁵ A/cm² ΔH₀*, the standard heat of activation = 26.5 kcal/mole CuS was tentatively identified as one of the reaction products. A reaction mechanism was discussed. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate

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