THERMODYNAMICS OF LIQUID BINARY (ALKANENITRILE-ALKANE) MIXTURES .1. EXPERIMENTAL EXCESS MOLAR VOLUME AT 298.15 K AND ITS INTERPRETATION WITH THE PRIGOGINE-FLORY-PATTERSON THEORY

Density measurements have been made by means of a vibrating tube densi tometer, at 298.15 K, over the whole composition range for 25 binary l iquid mixtures of propanenitrile, butanenitrile, pentanenitrile and he xanenitrile with several different hydrocarbons. Values of the molar e xcess volume, V-E, were derived and the results show a regular pattern of behaviour for each of the four sets of binary system. For a given alkanenitrile, the magnitude of V-E increases with the hydrocarbon cha in length and also for a given hydrocarbon, V-E decreases with the cha in length of the nitrile. The Prigogine-Flory-Patterson theory was app lied to analyse the experimental behaviour by calculating three differ ent contributions to V-E, i.e. interactional, free volume and internal pressure. The theory is capable of reproducing the main features of t he experimental V-E results by using a fitted binary interaction param eter.