浓硫酸中羟基乙酸的游离态含量及其总含量的测定  

Determination of the free state and total content of glycolic acid in concentrated sulfuric acid

作　　者：余维新[1] 贾绘如[1] 周拥华[1] 

机构地区：[1]西南化工研究设计院有限公司,四川成都610225

出　　处：《能源化工》2015年第1期79-82,共4页Energy Chemical Industry

摘　　要：针对水溶液电位滴定法无法将硫酸与羟基乙酸的滴定曲线突跃点分开,无法测定浓硫酸中羟基乙酸的问题,采用非水溶液电位滴定法,使用丙酮作为溶剂,对含有浓硫酸的羟基乙酸样品中的游离态羟基乙酸及其总含量进行了测定。以丙酮为溶剂,可以很好地将2种酸的滴定曲线突跃点区分开来,并能对游离的羟基乙酸做定量分析。此外,羟基乙酸自身容易失水生成二乙交酯和多交酯,通过碱水解,再采用上述方法,可以测定出羟基乙酸盐的含量,即得到羟基乙酸的总含量。试验表明:该方法准确性高、重现性较好、操作简便;但无法有效区分羟基乙酸和其他有机强酸。Because aqueous potentiometric titration method can not distinguish the jump point of titration curve of glycolic acid and sulfuric acid,so the content of glycolic acid in sulfuric acid can not be detected by aqueous potentiometric titration. Using anhydrous potentiometric titration,the free state and total content of glycolic acid in concentrated sulfuric acid are detected by using acetone as a solvent,which can distinguish the jump point of the two kinds of acid well. Furthermore,glycolic acid itself can easily condense to generate dehydration esters and lactide. Through alkaline hydrolysis of the esters,then using the above anhydrous potentiometric titration method,the content of glycolic acetate can be measured,so the total amount of glycolic acid can be detected. The results show that the method has advantages of high accuracy,good reproducibility and simple operation,but can not distinguish glycolic acid from other organic strong acid.

关 键 词：羟基乙酸 非水溶液电位滴定 丙酮 测定 

分 类 号：TQ111.17[化学工程—无机化工] O657.1[理学—分析化学]