The Dissolution Rate of Crystalline Glucose in Water -The Relation between the Dissolution Rate of α-D-Glucose after Saturation and the Rate Constant of Mutarotation-

Abstract

D-Glucose has two anomeric isomers (a- and 8-type). In crystalline state, D-glucose is of a-type. When crystalline D-glucose dissolves in water, part of the dissolved a-D-glucose changes into 8-D-glucose. These properties of D-glucose exhibit an interesting phenomenon concerning the dissolution rate of crystalline D-glucose.
In this study, the author attempted to derive a basic equation for determining the dissolution rate of crystalline D-glucose after the solution has been saturated with a-D-glucose. Experiments were conducted at 10-30° C in order to verify the equation. As a result of the experiments, it was clarified that the dissolution process of crystalline D-glucose has two rate-determining steps of diffusion and mutarotation. With the aid of this basic equation and the results of the experiments, it was made possible to measure the solubility of a-D-glucose. The derived rate equation is as follows:
where
Tg=Total concentration of D-glucose at time t, K=Tan 0 of linearlized mutual solubility curve, Pe=Solubility of 8-D-glucose at equilibrium, 1=Forward rate constant of mutarotation, I=Reverse rate constant of mutarotation, b=intercept of linearlized mutual solubility curve.