EXCESS ENTHALPY OF 4 PARTIALLY MISCIBLE BINARY-LIQUID MIXTURES NEAR THEIR CRITICAL SOLUTION TEMPERATURES

Heats of mixing for the n-hexane + methanol, 2-methylpropanolc acid + water, nitroethane + 2,2,4-trimethylpentane, and nHromethane + 1-butanol systems were measured as a function of composition at from six to eight temperatures bracketing each system's critical solution temperature. The estimated uncertainty in the results is less than 1.0%. Heats of mixing were endothermlc In all four systems. Above the critical solution temperature, heat of mixing curves plotted vs mole fraction of the first component were everywhere convex. Below the critical solution temperature, Intersections of the straight (two-phase) and curved (one-phase) heat of mixing lines were used to provide a calorlmetrlc estimate of the blnodal compositions. © 1990, American Chemical Society. All rights reserved.