Additivity of the partial molar volumes of organic compounds

Abstract

A critical test of additivity for partial molar volume has been made at 25 °C in CCl4 with polyethylene glycol dimethyl ethers, crown ethers, cycloalkanes, n-alkanes, and others. Plots of partial molar volume at infinite dilution [Formula: see text] against the properly chosen number of repeating unit (n) are linear except for small cyclic molecules, and the slopes of homologous straight chain and ring compounds are the same. The values of [Formula: see text] extrapolated to n = 0 for cycloalkanes and crown ethers support the validity of the contribution due to the translational kinetic energy that has been predicted recently on a theoretical basis. The importance of packing efficiencies around the solute molecules has been examined by means of simple models.