Volume 48, Issue 6 e70040
Research Article

Ethanol Antisolvent Effects on Solid–Liquid Equilibrium and Nucleation of Ammonium Magnesium Sulfate Hexahydrate

Tam Minh Le

Corresponding Author

Tam Minh Le

Department of Chemical Technology, Ho Chi Minh City University of Technology and Education, 1 Vo Van Ngan, Thu Duc, Ho Chi Minh City, 700000 Vietnam

E-mail: [email protected]

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Duc Hong Ta

Duc Hong Ta

Department of Chemical Process Equipment, Hanoi University of Science and Technology, 1 Dai Co Viet, Hanoi, 10000 Vietnam

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Binh Phuc Pham

Binh Phuc Pham

Department of Chemical Technology, Ho Chi Minh City University of Technology and Education, 1 Vo Van Ngan, Thu Duc, Ho Chi Minh City, 700000 Vietnam

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Son Loc Hua

Son Loc Hua

Department of Chemical Technology, Ho Chi Minh City University of Technology and Education, 1 Vo Van Ngan, Thu Duc, Ho Chi Minh City, 700000 Vietnam

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First published: 13 May 2025

Abstract

The characterization of a double salt synthesized from aqueous solutions of ammonium sulfate and magnesium sulfate is reported. Thermal analysis indicates that the resulting crystals incorporate six water molecules, yielding a compound with the composition (NH4)2Mg(SO4)2·6H2O. X-ray diffraction confirms the structural stability of the crystals in both water and ethanol–water mixtures. Two key aspects were investigated, including the thermodynamics of the solid–liquid equilibrium (SLE) and the kinetics of primary nucleation. SLE measurements reveal that ethanol acts as an antisolvent. The dissolution process is endothermic, with the enthalpy of dissolution increasing with ethanol content. The enthalpy of dissolution in a solvent containing 10 % (w/w) of ethanol is +21.92 kJ mol−1, compared to +17.14 kJ mol−1 in water. Furthermore, the nucleation process follows second-order kinetics, with the nucleation rate constant exhibiting a strong dependence on solvent composition.

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