乙醇-水溶剂中阿斯巴甜溶解度及介稳区的研究

在5～60 ℃温度范围内，研究阿斯巴甜在不同比例的乙醇-水混合溶剂中的溶解与超溶解特性，得到了阿斯巴甜的结晶介稳区，并推算出表观成核级数m，给出了成核速率方程。采用λh方程关联6 个体系的溶解度数据，并考察温度、溶剂组成、降温速率以及搅拌速率对结晶介稳区的影响。结果表明：阿斯巴甜的溶解度随着温度和乙醇质量分数的增加而增加，当质量比w=0.5时出现溶解度的协同效应；随着温度和乙醇质量分数的增加，阿斯巴甜结晶介稳区宽度减小；在相同条件下，搅拌速率的降低和降温速率的升高均会增大阿斯巴甜结晶介稳区的宽度。

Solubility and Metastable Zone of Aspartame in Ethanol-Aqueous Mixture

The solubility and super-solubility of aspartame in ethanol-aqueous mixture with different ethanol mass fractions
at 5–60 ℃ were determined, and the apparent nucleation order m was calculated. Meanwhile, the nucleation rate equation
was achieved. The surperstaturation curve and metastable region of aspartame were obtained. It was found that the solubility
data could be described well by the model of λh equation; in addition, the influences of temperature, solvent composition,
cooling rate and agitation rate on the width of metastable zone were explored. The results showed that the solubility of
aspartame in the selected solvents increased with an increase in temperature and ethanol mass fraction, and a synergistic
effect on solubility was observed at w = 0.5 (m/m). Contrary to the solubility, the width of metastable zone decreased with
increasing temperature and ethanol mass fraction; under the same experimental conditions, either decreasing agitation rate or
increasing cooling rate may broaden the width of metastable zone.