Hello,
I have a question of the melting temperature of the triethylene glycol. On MSDS, the melting temperature of the triethylene glycol is ~-7C. however, I put this liquid material in freezer (-18C) overnight, it still liquid.
Then, I use the DSC to see the crystal peak, but didn't find it to -40C.
Does anyone know triethylene glycol? Could you please explain why this doesnot become solid?
Thanks!
Junhua
Triethylene glycol is very hygroscopic and its freezing point decreases steeply with its humidity content; by about -1.6 ºC / wt% H2O for nearly pure glycol. Considerably uncertainty seemingly affects some published freezing or melting points for this glycol. You may possibly consider to dry it over anhydrous CaSO4, for a week or so, hereafter slowly distilling it fractionally under vacuum, preferably more than once. The water content can be rather accurately determined based on the refractive index.
Viscosity prevents freezing. In a high speed mixer It will freeze at the published temperature. Maybe 13 degrees Celsius by one reference.
http://www.chemicalland21.com/petrochemical/TEG.htm
do you know the concentration of TEG in vol or wt%? if it is pure, it should freeze at -7C if it is diluted at 60 wt%, the freezing point is -35 C. Check the freezing curve of TEG!
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