Coulometric titrations of bases in propylene carbonate using hydrogenpalladium and deuteriumpalladium generator electrodes.

The application of hydrogen and deuterium ions obtained by anodic oxidation of hydrogen and deuterium dissolved in palladium, for the coulometric determination of bases (both individual and in mixtures) in propylene carbonate, is described. The current-potential curves at a palladium anode for supporting electrolyte indicator, titrated bases, hydrogen dissolved in palladium and deuterium dissolved in palladium showed that hydrogen and deuterium are oxidized at much less positive potentials than the oxidation potentials of other substances present in the solution. The generated H(+) and D(+) ions were used for the titration of bases (pyridine, quinoline, triethylamine, n-butylaniline, 2,2'-dipiridyl and aminopyrine) with visual and potentiometric detection. The oxidation of hydrogen and deuterium proceeded with 100% current efficiency. Two-component mixtures of bases (aliphatic + aromatic amine) were titrated successfully by using two indicators, Eosin and Crystal Violet. The relative error of the determination with respect to each individual base determination, was less than 2.5% for quantities of bases ranging from 1 to 3 mg.

Coulometric generation of H(+) and D(+) ions in aqueous media by anodic oxidation of hydrogen and deuterium dissolved in palladium.

Coulometric generation of H(+) and D(+) ions in aqueous media by the oxidation of hydrogen and deuterium dissolved in palladium, is described. Hydrogen and deuterium dissolved in palladium were found to be oxidized at more negative potentials than the oxidation potentials of water and other components present. The H(+) and D(+) ions generated were used for the titration of tris(hydroxymethyl) aminomethane, piperidine, triethylamine and sodium tetraborate, the end-point being determined potentiometrically with a glass electrode and an SCE. In titrations of 0.001-0.1M solutions of the bases, the current efficiency was 100%.

Coulometric generation of protons by oxidation of hydrogen dissolved in palladium, in non-aqueous media.

Coulometric generation of H(+) ions by the oxidation of hydrogen dissolved in palladium, in media such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, acetic anhydride and acetic acid-acetic anhydride mixture, for use in titration of bases, has been investigated. The hydrogen is oxidized at potentials which are much more negative than those of the bases and other components present in the solution. Titrations of numerous bases have established that the oxidation is quantitative and proceeds with 100% current efficiency.