Crystallization is widely utilized as a purification technique in industries. Frequently in the course of crystallization, oiling-out, or termed liquid–liquid phase separation (LLPS), occurs and strongly influences the morphology of crystals. To research how to control and optimize the crystal habits when there is oiling-out, we investigated the β-alanine–water–isopropanol ternary system. Four ternary phase diagrams at 25, 30, 35, and 40 °C were constructed to provide a thermodynamic basis and guidance for the crystallization process. Moreover, to fully analyze the LLPS nucleation mechanism of β-alanine, the tie lines of the ternary diagram were constructed, and the site of nucleation was determined. Besides, on the basis of the phase diagram, evaporative crystallization was performed to investigate oiling-out crystallization. Furthermore, tabular crystals, octahedron shaped crystals, and spherical crystals were obtained respectively from normal crystallization, oiling-out crystallization, and quasi emulsion solvent diffusion crystallization.

中文翻译：

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基于三元相图的β-丙氨酸注油研究与形貌控制

结晶被广泛用作工业中的纯化技术。在结晶过程中，经常会出现上油现象或所谓的液相-液相分离（LLPS），并严重影响晶体的形态。为了研究出油时如何控制和优化晶体习惯，我们研究了β-丙氨酸-水-异丙醇三元体系。分别在25、30、35和40°C下构建了四个三元相图，为结晶过程提供了热力学基础和指导。此外，为了充分分析β-丙氨酸的LLPS成核机理，构建了三元图的联系线，并确定了成核位置。此外，根据相图，进行蒸发结晶以研究油析出结晶。此外，