Quaternary ammonium salts as colloidal electrolytes

Abstract

1. 1. Freezing point depressions in solutions of dodecylbenzyldimethylammonium chloride and sulfamate have been measured. The osmotic coefficients of the chloride fall midway between the generalized curves of McBain and Brady for straight and branched chain compounds. The sulfamate is less associated in dilute solutions than the chloride. 2. 2. The activity of hydrochloric acid has been measured electrometrically in mixtures of the above quaternary chloride and hydrochloric acid having constant total molality. 3. 3. Activity coefficients of hydrochloric acid have been measured at 3 temperatures in solutions of dodecylbenzyldimethylammonium chloride and its hexadecyl homologue containing a small proportion of added hydrochloric acid. 4. 4. The effect of simple salts on the activity of hydrochloric acid in such solutions has been investigated. 5. 5. From the data it is concluded that, in the concentration range where micelles are fully established, about 60% of the chloride ions are combined in the micelles of the dodecyl salt. It also appears that the concentration of simple quaternary cations falls as the quaternary salt concentration rises in this range.