Solid–Liquid Phase Equilibrium and Diagram of a l-Phenylalanine–Hydrogen Peroxide–Water Ternary System

Abstract

The equilibrium solubility data of L-phenylalanine (C 9 H 11 NO 2 ) dissolved in hydrogen peroxide solutions with different concentrations were obtained at 273.15 and 283.15 K by the use of a static method under ambient pressure (p = 101.2 kPa), and the ternary phase diagrams of the C 9 H 11 NO 2 − H 2 O 2 −H 2 O system were constructed according to the determined solubility. At 273.15 and 283.15 K, two neat solid phases were generated in the ternary C 9 H 11 NO 2 −H 2 O 2 −H 2 O system, which corresponded to C 9 H 11 NO 2 and Lphenylalanine perhydrate C 9 H 11 NO 2 •H 2 O 2 •0.5H 2 O. The adduct C 9 H 11 NO 2 • H 2 O 2 •0.5H 2 O was identified by the traditional method of Schreinemaker's wet residue. The solubilities of C 9 H 11 NO 2 and C 9 H 11 NO 2 •H 2 O 2 •0.5H 2 O in water slightly increased with a rise in temperature. The crystalline region of the adduct of C 9 H 11 NO 2 •H 2 O 2 •0.5H 2 O shrunk as the experimentation temperature increased, indicating a little effect of temperature on the yield of C 9 H 11 NO 2Finally, the effect of ethanol and sodium chloride on the phase equilibrium was studied. Adding a certain amount of ethanol and sodium chloride can reduce the solubility of L-phenylalanine.

Study on the solid–liquid equilibrium and thermodynamic model of the l-phenylalanine + l-tryptophan + water system

“…In addition, the conclusion was further verified by comparing with the existing literature. 29,41,42 This observation was consistent with the finding obtained by Schreinemaker's wet residue method. In addition, according to the results of XRD analysis, the characteristic peaks only exist between 10 and 40 degrees, so the XRD pattern between 10 and 40 degrees is only shown in Fig.…”

Ternary Phase Equilibrium of Adenine + Hydrogen Peroxide + Water and Characterization of the Adduct of Adenine with Hydrogen Peroxide

“…As the temperature increases, the co-saturated point shifts upward, the solubility increases slightly, and the crystallization zone of the C 5 H 5 N 5 ·H 2 O 2 adduct diminishes. Compared to the l -phenylalanine–hydrogen peroxide–water ternary system, due to poor aqueous solubility of adenine, the crystalline region of C 5 H 5 N 5 ·H 2 O 2 is larger than that of the adduct of l -phenylalanine with hydrogen peroxide …”

“…After establishing the equilibrium conditions, the solution systems were constructed by combining at least two or three components to provide an appropriate mass of the solid phase and solutions. The equilibrium of adenine in different concentrations of hydrogen peroxide solutions at 283.15 and 293.15 K under local pressure (about 101.1 kPa) was established by means of the isothermal saturation technique, which has been widely employed in previous studies. ,,− Initial solution systems were prepared by combining an excessive amount of adenine and aqueous hydrogen peroxide solutions with various concentrations of hydrogen peroxide ranging from 0 to 50 wt %. The stirring speed was set to around 200 rpm.…”

“…Here, Schreinemakers’ wet residue method − is introduced briefly. At least one liquid and one solid are present in a solid–liquid equilibrium system.…”

Cocrystal Phase Diagrams for Systems Formed by Succinic Acid, Fumaric Acid, and Benzoic Acid in Ethanol with Tebuconazole

“…The liquid–solid equilibrium for the ternary tebuconazole + succinic acid + ethanol, tebuconazole + fumaric acid + ethanol, and tebuconazole + benzoic acid + ethanol systems was constructed using the isothermal saturation method, which was used in previous work. − The experimental apparatus is given in Figure . The atmospheric pressure was approximately 101.2 kPa in all experiments.…”