Solid-liquid phase behavior of binary fatty acid mixtures. 1. Oleic acid/stearic acid and oleic acid/behenic acid mixtures.
Solid-liquid phase behavior of binary fatty acid mixtures was investigated by means of differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) for the mixture composed of oleic acid (OA) and stearic acid (SA) and that composed of OA and behenic acid (BA). The DSC results provided a monotectic type T-X phase diagram for these mixtures, from which it was suggested that the two fatty acid species are completely immiscible in a solid phase regardless of the two polymorphs of OA, i.e., alpha-form or gamma-form. The solid phase immiscibility was confirmed by the FT-IR observation that the spectra obtained for the mixtures correspond to the superposition of the two spectra for respective components. Thermodynamic analysis of liquidus line demonstrated that OA and SA form an ideal mixture in a liquid phase, whereas the mixing of OA and BA in a liquid phase is slightly non-ideal.
Inoue
Tohru
T
Department of Chemistry, Faculty of Science, Fukuoka University, Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan. inouetr@fukuoka-u.ac.jp
Hisatsugu
Yusuke
Y
Yamamoto
Reiri
R
Suzuki
Masao
M
D002152:Calorimetry, Differential Scanning; D005227:Fatty Acids / Q000737:chemistry*; D019301:Oleic Acid / Q000737:chemistry*; D044367:Phase Transition; D017550:Spectroscopy, Fourier Transform Infrared; D013229:Stearic Acids / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
D005227:Fatty Acids; D013229:Stearic Acids; D019301:Oleic Acid; C031183:stearic acid; C007547:behenic acid