THE EFFECT OF CERTAIN ADDITION AGENTS ON THE PHYSICAL STATES OF SODIUM SOAPS

Abstract

The effect of glycerol and of polar and non-polar mineral oils on the density–temperature relations of sodium stearate and sodium oleate have been measured. A non-polar solvent such as a high V.I. oil has no effect, and may be regarded as an inert diluent. Glycerol and low V.I. oils have similar effects on the physical states of the soap. Up to the unidimensional melting point of the soap, the polar solvents have no effect. Above this point, however, an increasing effect is obtained both with increase in temperature and with amount of solvent. The effect is particularly marked above the plasticity point but may be large also in the region of the bidimensional melting point of the soap. The orienting effect of the non-polar hydrocarbon chain on the polar grouping of the soap in the presence of a polar solvent is discussed. The influence of excess acid and alkali in the soap is described.