Polythermal study of phase behavior and extractive crystallization of salt in the ternary system ammonium sulfate – water – polyethylene glycol-1500

Phase equilibria and solubility have been studied by the visual polythermal method in mixtures of components in nine sections of the composition triangle in the range of 10–70° C in the ternary system ammonium sulfate – water – polyethyleneglycol-1500 (PEG-1500)...

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Main Authors: Karagulova, Madina A., Kirilina, Diana R., Danilina, Veronika V., Tsesarenkova, Victoria M., Cherkasov, Dmitry G.
Format: Article
Language:English
Published: Saratov State University 2025-06-01
Series:Известия Саратовского университета. Новая серия: Серия Химия. Биология. Экология
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Online Access:https://ichbe.sgu.ru/sites/ichbe.sgu.ru/files/text-pdf/2025/07/himiya-2025-2-171-183.pdf
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Summary:Phase equilibria and solubility have been studied by the visual polythermal method in mixtures of components in nine sections of the composition triangle in the range of 10–70° C in the ternary system ammonium sulfate – water – polyethyleneglycol-1500 (PEG-1500). The dependence of the compositions of solutions corresponding to the critical solubility points of the stratifi cation region on temperature has been found using the liquid phase volume ratio method. Isothermal phase diagrams of the studied ternary system have been constructed at 10.0, 20.0, 40.0, 50.0 and 70.0°C, the solubility of the components has been determined. It has been found that in the range of 10.0–40.0° C, a triangle of the eutectic state exists on the isothermal diagrams. At all temperatures of the study range, a monotectic triangle with adjacent fi elds of saturated solutions and stratifi cation is realized on the isotherms. The coeffi cients of PEG-1500 distribution between the equilibrium liquid phases of the monotectic state have been calculated. It has been found that ammonium sulfate eff ectively salts out PEG-1500 in the range of 10.0–70.0° C, while the content of the organic component in the aqueous phase is minimal (0.1–0.2 wt.%). Mixtures of the components of the studied system can be recommended for the extraction of hydrophilic molecules without introducing other compounds. It has been found that PEG-1500 exhibits high effi ciency as an ammonium sulfate antisolvent, which allows this salt to be extracted with high yields from unsaturated aqueous solutions at temperatures close to the standard one. With a decrease in temperature and an increase in the content of PEG-1500 in the water-salt mixture, the yield of salt crystals increases. It has been found that for a 38 wt.% ammonium sulfate solution with the introduction of 60 wt.% PEG-1500, the maximum yield of salt crystals (96.4%) has been observed at 30.0° C.
ISSN:1816-9775
2541-8971