乙醇酸在水中溶解度的测定与关联

采用结晶法分离提纯乙醇酸时,乙醇酸在水中的溶解度数据至关重要,特别是在低温下和高浓度时乙醇酸的溶解度数据目前尚未有系统的研究报道。采用平衡法测定了257.6～313.51 K乙醇酸在水中的溶解度,并用Van’t Hoff方程、Apelblat方程、λh方程、Wilson方程和NRTL方程对实验数据进行关联。结果表明:乙醇酸在水中的溶解度随着温度的升高而增加,上述5种模型对乙醇酸在水中溶解度的关联效果均较好,相关系数(R²)均在0.99以上,平均相对误差(ARD)均小于2.64%,其中,λh方程的关联效果最好,平均相对误差(ARD)约1.06%。实验得到的溶解度数据和关联结果对乙醇酸结晶分离技术的开发具有非常重要的意义。

MEASUREMENT AND CORRELATION OF SOLUBILITY OF GLYCOLIC ACID IN WATER

When glycolic acid is separated and purified by crystallization,the solubility of glycolic acid in water is very important.However,its solubility data at low temperature and high concentration has not been systematically studied.The solubility of glycolic acid in water from 257.6 to 313.51 K(-15.5540.36℃)was measured by equilibrium method,and the experimental data were correlated by Van’t Hoff equation,Apelblat equation,λh equation,Wilson equation and NRTL equation.The results showed that the solubility of glycolic acid in water increased with the increasing temperature.The above five models can be well used to correlate the solubility of glycolic acid in water.The correlation coefficients(R2)are all above 0.99,and the average relative deviation(ARD)are all less than 2.64%.The correlation result ofλh equation is the best and the average relative deviation(ARD)is about 1.06%.The solubility data and correlation results are very useful for the development of glycolic acid crystallization process.