基于拉曼光谱的聚酯过程酯化反应中清晰点的在线检测

现有的人工采样分析方法如折光指数法、色谱法等操作复杂,存在时间上的滞后和人为误差,无法实时评估聚酯生产中的酯化反应过程,确定反应的清晰点。为此,该文搭建了以1064 nm为激光波长的在线拉曼分析系统,对对苯二甲酸(PTA)和1,3-丙二醇(PDO)生成聚对苯二甲酸丙二醇酯(PTT)的酯化反应过程进行光谱连续采集和处理。利用主成分分析法提取光谱信息,并结合酯化反应原理,利用位于1604 cm^-1附近的苯环基团和位于1720 cm^-1处的芳酯基团的拉曼特征峰面积比,建立了一种用于确定清晰点的定性分析方法。结果表明:拉曼光谱分析法可以准确反映聚酯过程酯化反应中的清晰点,且具有实时性好、操作方便、分析速度快的优势,可为聚酯生产的工艺控制和产品品质控制提供参考。

Online Detection of Clear Point in Esterification Process of Polyester Production Based on Raman Spectroscopy

Current manual sampling and analysis methods,such as refractive index measurement,chromatography,etc.,have complex operations,time lags and human errors.Therefore,they cannot be used to evaluate the esterification process in polyester production in real time and determine the clear point of the reaction.In this article,an online Raman analysis system with 1 064 nm as the laser wavelength was set up to collect continuously the spectra of the esterification reaction between terephthalic acid(PTA) and 1,3-propanediol(PDO) to create poly(tri methylene terephthalate)(PTT),while using Savitzky-Golay algorithm to make baseline correction on the collected spectra.The principal component analysis was used to extract the spectral information.Based on the principle of esterification process,a qualitative analysis method was established to determine the clear point by using the area ratio for Raman characteristic peaks of benzene loop located near 1 604 cm-1 and ester group located at 1 720 cm-1.Results showed that the developed Raman spectroscopy could accurately reflect the clear point in the esterification process of polyester prodction,With the advantages of good real time performance,simple operation and rapid analysis,it provides a reference for the process control and product quality control of polyester production.