The solubility of quercetin and its thermal degradation was studied in CO2-expanded ethanol and ethyl lactate. An equipment setup was constructed that enabled the separation of the products of degradation while quantifying the solubility of quercetin. Three different conditions of temperature were analyzed (308, 323, and 343 K) at 10 MPa. Higher solubility and thermal degradation of quercetin were observed for CO2-expanded ethyl lactate in comparison with CO2-expanded ethanol. At the same time, as the amount of CO2 was increased in the CO2-expanded liquids mixtures, the thermal degradation of quercetin decreased for almost all the conditions of temperature considered in this work. The importance of considering thermal degradation while performing solubility measurements of compounds that are thermally unstable such as quercetin was highlighted.

中文翻译：

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槲皮素在 CO2 膨胀液体中的溶解度和热降解

研究了槲皮素在 CO2 膨胀乙醇和乳酸乙酯中的溶解度及其热降解。构建的设备设置能够在量化槲皮素溶解度的同时分离降解产物。在 10 MPa 下分析了三种不同的温度条件（308、323 和 343 K）。与 CO2 膨胀的乙醇相比，CO2 膨胀的乳酸乙酯的槲皮素具有更高的溶解度和热降解性。同时，随着 CO2 膨胀液体混合物中 CO2 量的增加，槲皮素的热降解在本工作中考虑的几乎所有温度条件下都会降低。强调了在对热不稳定的化合物（如槲皮素）进行溶解度测量时考虑热降解的重要性。