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采用动态法测定了熊果酸在室温范围(20和30℃)、pH7～10、含醇60%～90%(ω)的乙醇-水溶液中的溶解度.溶解度随pH和醇浓度增大而增大,在pH9～10内,随pH升高而快速增大,并随醇浓度升高显著增大.溶解度对pH较敏感,调酸反应结晶为熊果酸较适宜的结晶方式.用经验关联式对每一温度下80组溶解度数据进行了关联,相关系数均达0.998.用激光监测法测定了室温范围内熊果酸在乙醇-水中调酸反应结晶时的介稳区,介稳区宽度随熊果酸饱和浓度增大呈先减小后增大的趋势,且温度越高介稳区越宽.20℃下由枇杷叶得到的80%熊果酸粗品在合适酸浓度和加酸速率下经3次反应结晶可得到纯度98%以上的棒状、白色有光泽的熊果酸晶体粉末,总收率为78%.
The solubility of ursolic acid in ethanol-water solution containing 60% ~ 90% (ω) of alcohol at pH 7 ~ 10 at room temperature (20 and 30 ℃) was determined by the dynamic method. The solubility increased with the increase of pH and alcohol concentration Large, pH9 ~ 10, with the rapid increase of pH, and with the alcohol concentration increased significantly.Pollution is more sensitive to pH, acidification reaction ursolic acid crystallization is the more appropriate way to use empirical correlation The correlation coefficients of the solubility data of 80 groups at each temperature were 0.998. The metastable zone, the metastable zone width of ursolic acid in ethanol-water under the acid reaction were measured by laser monitoring method With the increase of the concentration of ursolic acid, the concentration of ursolic acid firstly decreased and then increased, and the more the temperature, the more stable the metastable region.The crude extract of ursolic acid 80% obtained from loquat leaf at 20 ° C under the appropriate acid concentration and acid addition rate 3 times the reaction crystallization can be obtained more than 98% purity of the rod, white shiny ursolic acid crystal powder, the total yield was 78%.