Predictions with UNIFAC of liquid-solid phase diagrams: application to water-sucrose-glucose, water-sucrose-fructose and water-xylose-mannose

• Published in: Journal of crystal growth Vol. 128; no. 1-4; pp. 1245 - 1249
• Main Authors: Gabas, N., Laguérie, C.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.1993; Elsevier
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Solubility; Solutions
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/S0022-0248(07)80130-8

The objective of this study is to develop a prediction model of solid-liquid equilibria based on the UNIFAC method which is applicable to sugar systems. Three new groups, X, F and G, representing respectively the cyclic structure of D-xylose, D-fructose and D-glucose are introduced and new interaction parameters for these groups are calculated. The use of groups X, F and G permits the identification of mannose as composed of X, OH and CH2 and of sucrose as composed of G, F and -O-. The model is tested on three ternary systems: water-sucrose-D-glucose; water-sucrose-D-fructose; water-D-xylose-D-mannose. The results compare favourably with the experimental data except in the invariant point region, corresponding to saturation with both solutes. A similar technique could be applied in the prediction of the behaviour of other sugar systems containing these basic rings.