DISSOLUTION OF SOME NORMAL-ALKANES IN ETHYLBENZENE - DEDUCTION OF THEENTHALPY OF MIXING 2 N-ALKANES IN THE SOLID-STATE

Drop calorimetry has been used to measure the heat changes occurring u pon the dissolution of some single n-alkanes (octadecane to tetracosan e) or their binary mixtures (C22H46-C24H50 and C23H48-C24H50), in ethy lbenzene, at 311.45 K. The enthalpy changes measured show the even-odd alternation effect known for n-alkanes. The binary mixtures show pron ounced non-ideality. Their enthalpies of formation at 293.15 K were de duced from the measurement of their heats of dissolution in ethylbenze ne and found to depend on the crystal type. It is shown that these mix tures may consist of several phases of solid solutions. (C) 1997 Elsev ier Science B.V.