Coulometric titration of acids in non-aqueous solvents.

Coulometric titrations of mineral acids, sulphonic acids, carboxylic acids, enols, imides and phenols have been carried out in t-butanol or in acetone with electrically generated tetrabutylammonium hydroxide. Either a potentiometric titration or a visual indicator end-point may be used. The amount of acid titrated ranges from 10 to 60 muequiv, and the precision and accuracy of the method are excellent.

Acid-base indicator transition ranges in pyridine.

The transition ranges of thirteen acid-base indicators in pyridine have been measured by visual and by photometric means. The transition ranges are given in terms of potentials measured with a glass - modified calomel electrode system. These data permit the selection of a suitable indicator for the titration in pyridine of any acid or acid mixture which does not give highly coloured products and has a good potentiometric break at the equivalence point.