Solid-Liquid Equilibrium in the System 2-Keto-L-Gulonic Acid + L-Ascorbic Acid + Water

Area of Science:

• Physical Chemistry
• Chemical Engineering
• Materials Science

Background:

• Understanding solid-liquid equilibrium (SLE) is crucial for industrial processes involving chemical mixtures.
• Ascorbic acid (vitamin C) and 2-keto-L-gulonic acid (HKGA) are important compounds with potential industrial applications.
• Accurate phase diagrams and solubility data are essential for process design and optimization.

Purpose of the Study:

• To experimentally investigate the solid-liquid equilibrium (SLE) in the ternary system of HKGA, vitamin C, and water.
• To determine the dissociation and solubility constants of vitamin C as a function of temperature.
• To develop and validate a physicochemical model for predicting SLE in this system.

Main Methods:

• Experimental determination of solid-liquid equilibrium data at various temperatures (276 K to 308 K) and ambient pressure.
• Phase diagram construction for the ternary system, identifying eutonic points.
• Application of an extended Debye-Hückel theory to develop a physicochemical model.

Main Results:

• Phase diagrams with a single eutonic point were successfully obtained for all investigated temperatures.
• The dissociation and solubility constants of vitamin C were determined across the temperature range.
• The developed physicochemical model demonstrated excellent agreement with experimental SLE data.

Conclusions:

• The study provides valuable experimental data and a predictive model for the HKGA + vitamin C + water system.
• The findings are relevant for optimizing industrial processes involving these compounds.
• The physicochemical model offers a robust tool for understanding and predicting solubility behavior.