The purification of 4,4′‐diaminodiphenyl ether (ODA) was investigated. ODA, which contained impurities, was sublimated and anti‐solvent (ethanol)‐crystallized in N‐dimethylformamide (DMF). Fourier transform infrared (FTIR) results revealed that the sublimated crystal was basically identical with the pure ODA sample. The influence of different amounts of ethanol on particle size distribution was analyzed during anti‐solvent crystallization. The morphology of the ODA crystal was examined by scanning electron microscopy (SEM). The color of the sample enhanced from a brown powder to a colorless granular crystal. The purity of the sample could be increased from about 30 % to 87 %. With the operations of sublimation and anti‐solvent crystallization, the purity, crystal morphology, and particle size distribution of ODA were significantly improved.

中文翻译：

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4,4'-二氨基二苯醚的结晶和纯化

研究了4,4'-二氨基二苯醚（ODA）的纯化。将含有杂质的ODA升华并在N中反溶剂（乙醇）结晶-二甲基甲酰胺（DMF）。傅里叶变换红外（FTIR）结果表明，升华后的晶体与纯ODA样品基本相同。在反溶剂结晶过程中分析了不同量的乙醇对粒度分布的影响。通过扫描电子显微镜（SEM）检查ODA晶体的形态。样品的颜色从棕色粉末增强为无色颗粒状晶体。样品的纯度可以从大约30％增加到87％。通过升华和反溶剂结晶操作，ODA的纯度，晶体形态和粒径分布得到了显着改善。