返滴定法测定聚酯浆料中对苯二甲酸含量

在聚酯生产中，需随时对生产聚酯中间产品浆料中的对苯二甲酸（简称PTA）的含量进行准确测量，辽阳石油化纤公司（简称辽化）聚酯厂现仍采用化学方法测量，即以讹咬为溶剂，用NaOH直接滴定PTA，吡啶毒性大，长期使用对人体会造成严重的损害，并且污染环境．现以返滴定方法测定浆料中对苯二甲酸的含量，向浆料中加入过量标准NaOH溶液，然后用盐酸标准溶液滴定过量NaOH溶液，以酚酞为指示剂指示终点．根据所消耗盐酸的量和加入NaOH的量计算出PTA的含量．此法快速、简便、无毒，可用于化工生产监测．

Determination of Content of Benzene Dicarboxylic Acid in Polyester Paste with Titrimetric Method

In polyester production,the determination of PTA in the mmedium product paste isneeded at any time,and Liaohua Polyestor Plant still determine the content of PTA with the traditional chemical method, with pyridine as solvent and NaOH to titrimete PTA directly,while pyridine isvery poisoneous and pollutes the environment. We determine the content of PTA in polyester paste,add a large amount of standard NaOH solution to the paste,with hydrochloric acid standard solution totitriminate the big amount of NaOH solution,and use phenol phthalein as indicator according to theconsumption of hydrochoric acid and the addition of NaOH. We can calculate the content of PTA in thepaste. This is a quick. simple and non poisonous method which can be used in the monitering and determining of chemical production.