乙醇-水体系中熊果酸的溶解度测定和反应结晶  

Solubility and Reaction Crystallization of Ursolic Acid in Ethanol-Water System

作　　者：唐凤翔[1] 朱忠敏[1] 郑磊[1] 郭仲利[1] 郭养浩[1] 

机构地区：[1]福州大学化学化工学院,福建福州350108

出　　处：《过程工程学报》2011年第3期386-390,共5页The Chinese Journal of Process Engineering

基　　金：福建省科技厅资助项目(编号:2006F1006)

摘　　要：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 system was measured in the pH value range of 7-10 and ethanol concentration range of 60%-90%（-） under room temperatures （20 and 30℃） using a dynamic method. It was found that increasing pH value and ethanol concentration resulted in the enhancement of solubility. The ursolic acid solubility increased sharply with pH value only at higher pH range （9-10）, and just in this pH range, the increase of ethanol concentration could significantly raise the solubility. Ursolic acid solubility was more sensitive to pH value than ethanol concentration at room temperatures and hence reaction crystallization by adding acid was suitable to ursolic acid recovery. Based on the variation trend of solubility with pH value and ethanol concentration, empirical equations were used to correlate the relationship between solubility and pH and ethanol concentration with a high relative coefficient of 0.998. In addition, the reaction crystallization metastable zones of ursolic acid in ethanol-water system were determined using laser monitoring technique. The metastable zone width （-pH） decreased, then increased with increasing saturation concentration of ursolic acid and seemed to increase with the increase of temperature. When 80% ursolic acid from loquat leaves was dissolved in 90%（-） ethanol-water at pH 10, a bench-scale reaction crystallization process was carried out at appropriate acid concentration and acid-adding rate, and 98% ursolic acid was obtained with a overall yield of 78%. The ursolic acid crystals were rod-like and white glossy particles.

关 键 词：熊果酸 溶解度 介稳区 乙醇-水 反应结晶 

分 类 号：TQ460.64[化学工程—制药化工]