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.

中文翻译：

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二元脂肪酸混合物的固液相行为。1.油酸/硬脂酸和油酸/山hen酸的混合物。

通过差示扫描量热法（DSC）和傅里叶变换红外光谱（FT-IR）研究了由油酸（OA）和硬脂酸（SA）组成的混合物的二元脂肪酸混合物的固液相行为OA和山hen酸（BA）。DSC结果为这些混合物提供了单晶型TX相图，从中可以看出，无论OA的两种多晶型（即α形式还是γ形式），两种脂肪酸在固相中都是完全不混溶的。通过FT-IR观察证实了固相不溶混性，对于混合物获得的光谱对应于各个组分的两个光谱的叠加。液相线的热力学分析表明，OA和SA在液相中形成理想的混合物，