Hello, I have an old (5 yr) sample of Ethylene glycol(EG) that I have used as a plasticizer, but it is cloudy. I have already purchase new material and this new material is completely transparent. I have sent to FTIR and TGA. FTIR shows almost complete match to EG. and TGA in cloudy sample shows a 0.16% wt consentration of somting other than EG by comparing boiling points. Transparent sample has 100% wt loss at ~193C.
What could be the cause of this cloudy material? how could I determine what it is?
Whilst not a precise answer, ethylene glycol is known to undergo free radical oxidation reactions - Dow corning literature and other literature references report compounds formed. Those reported would generally be water soluble your extended storage period may lead to the formation of other compounds. If the sample is cloudy then perhaps your products are more polymeric in nature. At such an estimated low level FTIR is probably unlikely to be able to give any indication of the identity of the impurity. Suggested methods would be dissolution in a solvent and GC/MS analysis or if sufficient bulk liquid is available centrifuge or filter the EG to obtain a sample of the suspended material for analysis.
Hi I think with ethylene glycol being liquid it is best to measure characteristics of the physical chemistry of ethylene glycol to ensure the purity of ethylene glycol.
Because FT-IR and TGA analysis are better for solid compounds. I suggest that you measure the density, viscosity, or Refractive index of ethylene glycol and compare it with the standard sample.
Hi, ethylene glycol may be slightly acidified or polymerized with oxygen.
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