Solubilities of tetracosane in hydrocarbon solvents

Abstract

The solubilities of tetracosane (n-C[sub 24]H[sub 50]) in heptane (n-C[sub 7]H[sub 16]), dodecane (n-C[sub 12]H[sub 26]), a mixture of isomers of decahydronaphthalene (C[sub 10]H[sub 18]), and m and p-xylene (C[sub 8]H[sub 10]) have been determined over the temperature range 279.3--305.8 K. These solvents were chosen as being representative of the types of molecules present in fuel oils. The results are well described by the equation ln x[sub 2] = [minus]([Delta]H[sup d]/RT) + ([Delta]S[sup d]/R) for which the parameters [Delta]H[sup d] and [Delta]S[sup d] are given. The liquid-phase activity coefficients for the solid at 293.2 K have been derived from the measured solubilities and compared with values calculated from the Scatchard-Hildebrand equation and the UNIFAC group contribution method. Relatively good agreement is obtained using the Scatchard-Hildebrand equation, especially in the case of normal hydrocarbon solvents.