Glycol Uv Transmittance

Ethylene glycol is an important chemical product. Now a particularly important use of ethylene glycol is in the production of polyester fibers. Ethylene glycol used in the manufacture of polyester fibers generally must be of exceptionally high purity and has to meet a rigid UV transmittance specification. In this paper, impurities were concentrated on an ion-exchange resin, then eluted by hydrochloric acid-methanol solution, and detected by gas chromatography-mass spectrometry. More than ten impurities were detected. The paper pointed out: there are two kinds of impurities which affect commercial ethylene glycol UV transmittance. One kind is organic acids, which contain one or more carbon atoms, and their derivates, the other is aldehyde and ketone which contain one or two carbonyls. In order to improve the UV transmittance of the ethylene glycol, these two kinds of impurities must be removed at the same time.In this paper, a bed of anion exchange resin followed by a bed of cation exchange resin was used to absorbed and catalyzed the aqueous mixture of ethylene glycols, which contain about 15 wt% water, then the product stream which has a reduced UV light absorbance was sent to be distilled. The final monoethylene glycol product has a UV transmittance over 90% at 220nm, 95% at 275nm and 98% at 350nm.