Identification of impurities affecting commercial ethylene glycol UV transmittance.
As a raw material for making polyesters, ethylene glycol has a special specification of UV transmittance. At present, ethylene glycol produced by some plants still has low UV transmittance rendering it unsuitable for use in polyester production. In this paper, a method was developed for the identification of the impurities that cause commercial ethylene glycol to have low UV transmittance, using solid-phase extraction (SPE) and some analytical techniques such as high-performance liquid chromatography, gas chromatography-mass spectrometry and gas chromatography-Fourier transform infrared spectroscopy. The major UV-absorbing impurities were identified as some alkyl homologues of 2-hydroxycyclopent-2-en-1-one, including 2-hydroxy-3,5-dimethylcyclopent-2-en-1-one, 2-hydroxy-3-methylcyclopent-2-en-1-one, 2-hydroxy-3,4-dimethylcyclopent-2-en-1-one, 2-hydroxy-3-ethyl-4-methylcyclopent-2-en-1-one and 2-hydroxy-3-ethylcyclopent-2-en-1-one. Their concentrations were estimated to be less than 2 microg ml(-1). It is believed that with the above results, ethylene glycol-producing plants might make process improvements to remove these impurities more effectively and more easily.
Zhang
Y
Y
Shanghai Research Institute of Petrochemical Technology, China Petrochemical Group Corporation.
Feng
Y
Y
Lu
W
W
D002851:Chromatography, High Pressure Liquid; D005026:Ethylene Glycols / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D012015:Reference Standards; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared
D005026:Ethylene Glycols