An Irregularity in the Solvent Powers of Paraffins

Abstract

The solubility relations of n‐heptane with f‐heptane, iodine, sulfur, stannic iodide, and phosphorus are all accounted for within the usual limits of accuracy for regular solution theory by a solubility parameter 8.1 instead of the value 7.45 derived from its energy of vaporization per cc. Solutions of 2,2,4‐trimethyl pentane with f‐heptane and with iodine are similarly accounted for by the empirical value 7.45 instead of 6.85. Such an adjustment for paraffins is a practical alternative to the treatment used by Simons and Dunlap for the system n‐pentane, ``pentforane,'' which they recently reported upon, and is, at the same time, consistent with their assumption that the exceptional behavior of paraffins is to be attributed to an irregularity in their mutual repulsions.