Molal volumes of some<i>n</i>‐Fatty acids and their methyl and ethyl esters

Abstract

The densities of some pure methyl and ethyl esters of n ‐fatty acids were determined at temperatures between 10° to 80°C. The molal volumes of these esters and the long‐chain fatty acids were correlated with temperature and chainlength. The reciprocals of the average methylene contribution at long‐chain and the end group contribution to the molal volumes were found to be linear functions of the temperature. With the introduction of a correction term to account for mutual interaction of the end groups, three equations, one for each of the esters and the acids, were developed. These equations were used to calculate the molal values of the acids with carbon numbers up to 30 and up to 20 for the esters at temperatures ranging from 10° to 100°C. Excellent agreements were obtained between the molal volumes calculated by the equations and those obtained from the literature and experimental data.