摘要
采用pH值电位滴定法测定了扁桃酸的离解常数,采用高效液相色谱法考察了扁桃酸在不同溶剂中的溶解度曲线和在苯-水体系中于不同pH值条件时的分配率,建立了热苯萃取和冷却结晶的扁桃酸纯化工艺.研究结果显示,扁桃酸的离解常数pKa值为5.28;扁桃酸在水和苯中的溶解度曲线可分别表示为:S=38.756e0.0354t和S=0.2746e0.0649t;扁桃酸在水和苯中的溶解度差值曲线可分别表示为:ΔS/S1=0.1196t-2.712和ΔS/S1=0.3688e0.0723t;苯是最适合用于冷却结晶的溶剂;热苯萃取扁桃酸的苯水比例可选为1∶1;降低pH值有利于扁桃酸在苯中的分配.
A new method for the separation and purification of chiral mandelic acid by heated benzene extraction and refrigeration crystal was established. The ionization constant of mandelic acid was mensurated by pH potentiometer titration. The solubility curve of mandelic acid in different solvent and the distribute ratio of mandelic acid in benzene-water system in different pH condition were determine by HPLC. The results showed that the ionization constant pK_a of mandelic acid was 5.28, the solubility of mandelic acid in water and benzene could be respectively denoted with S=38.756e^(0.0354t) and S=(0.274?6e)^(0.064?9t), and the difference of solubility of mandelic acid in water and benzene could be respectively denoted with ΔS/S_1= 0.119?6t-2.712 and ΔS/S_1=0.368?8e^(0.072?3t). The ratio of benzene to water was chosed 1∶1 in the technology of heated benzene extraction, less pH value was propitious to the distribution of mandelic acid in benzene solvent, and benzene solvent was optimum solvent for refrigeration crystal of mandelic acid.
出处
《福州大学学报（自然科学版）》
CAS
CSCD
北大核心
2005年第3期395-399,共5页
Journal of Fuzhou University(Natural Science Edition)
基金
福建省自然科学基金计划资助项目(项目编号:E0310019)
福建省科委重点项目(项目编号:2003H023)
关键词
手性药物
扁桃酸
离解常数
溶解度
测定
chiral drugs
mandelic acid
ionization constant
solubility
mensuration
