Maximum density effects in dilute aqueous solutions of alcohols and amines

Abstract

The effect of dipropylamines and dibutylamines on the temperature of the maximum density of water has been determined as a function of amine concentration. These effects have been related to the temperature coefficient of the volume of mixing which for aqueous solutions of both amines and alcohols is negative, giving rise to a positive contribution towards the shift of the temperature of maximum density. This effect is attributed to the stabilization by the solute of residual long-range order present in liquid water, and a comparison is made with the clathrate hydrate structures.