The binary (solid + liquid) phase diagrams of (caprylic or capric acid) + (1-octanol or 1-decanol)

•SLE of mixtures of caprylic acid, (capric acid + 1-octanol), 1-decanol were studied.•Experimental data were obtained through DSC and Stepscan DSC.•Systems presented eutectic and peritectic points.•Liquidus line was modeled using Margules and NRTL models.•Solid phase was modeled using the Slaughter and Doherty approach.

In the present study the phase diagrams of four (fatty acid + fatty alcohol) binary mixtures composed of caprylic (C8O2) or capric acid (C10O2) + 1-octanol (C8OH) or 1-decanol (C10OH) were obtained by differential scanning calorimetry (DSC). Eutectic and peritectic reactions occurred in the systems. In standard DSC analyses of the (C8O2 + C10OH) and (C10O2 + C8OH) systems, an exothermic transition occurs in association with the melting of a metastable phase. A Stepscan DSC method was used in order to avoid the formation of this metastable phase during the heating of the mixtures. The approach suggested by Slaughter and Doherty (1995) [24] was used for modeling the solid phase, and the Margules 2-suffix, Margules 3-suffix and NRTL models were applied for calculating the activity coefficients of the liquid phase. The best modeling results were obtained using the Margules-3-suffix with an average deviation between experimental and calculated values ranging from T = (0.3 to 0.9) K.