Abstract: The bench-scale cooling crystallization for ternary solution of L-ascorbic acid (Vitamin C)
was studied. The solid-liquid phase diagram of Vitamin C-water-ethanol system was obtained
on the basis of differential scanning calorimeter (DSC) curves. The heat of crystallization
of Vitamin C was calculated with the aid of quantitative analysis. According to the
population balance equation under unsteady state, the rates of nucleation and growth were
determined. The parameters of crystallization kinetics equations were estimated by
regression of experimental data. Crystal morphology and size were determined with x-ray
diffraction and TA Ⅱ Coulter Counter.

Key words: Vitamin C, crystallization, thermodynamics, DSC, kinetics

摘要： The bench-scale cooling crystallization for ternary solution of L-ascorbic acid (Vitamin C)
was studied. The solid-liquid phase diagram of Vitamin C-water-ethanol system was obtained
on the basis of differential scanning calorimeter (DSC) curves. The heat of crystallization
of Vitamin C was calculated with the aid of quantitative analysis. According to the
population balance equation under unsteady state, the rates of nucleation and growth were
determined. The parameters of crystallization kinetics equations were estimated by
regression of experimental data. Crystal morphology and size were determined with x-ray
diffraction and TA Ⅱ Coulter Counter.

关键词: Vitamin C;crystallization;thermodynamics;DSC;kinetics