Triethanolamine crystallization

I found a gallon of triethanolamine in one of my storage closet and while holding it I realized that it had gone though crystallization.  I checked the smell and it is definitely TEA.  Can it heat it up in a bath to "melt" the  crystallization and if so, will it be usable?  Thanks for your help! 


  • PharmaPharma Member, Pharmacist
    TEA doesn't crystallise. If there's crystals inside, it's not TEA but probably a degradation product or something else entirely.
  • Here's a picture of an example of triethanolamine solidifying.  It certainly looks like crystallization.

    "Triethanolamine appears as colorless oily liquid with the smell of ammonia. It is easy to absorb water and will turn into brown color when being exposed to the air and the light. At low temperature, it will become colorless or pale yellow cubic crystal."

    This was stored in my unheated garage several years ago...
  • PharmaPharma Member, Pharmacist
    Ups, sorry, my bad. I was mentally at triethylamine instead of triethanolamine.
    The latter has (I did have to look it up, I admit) a melting point around room temperature and simply heating it a little bit will re-liquefy everything and you're good to go. Even taking the supernatant would work but is likely to contain more impurities than the crystals. Re-crystallisation cycles are used to purify different things ;) .
    Is it still useful after all this years? Running some purity tests would help...
  • Pharma, thanks for getting back to me on this.  I should have remembered another time when triethylamine and triethanolamine were confused with each other... no problem!  I have a half gallon I'm using and another 2 gallons I found after posting this which are fine but I'll probably experiment with it to see what happens with it!  Thanks for your input!
  • VnnilVnnil Member
    You can add 10-15% of water to lower the freeze point.
  • Vnnil said:
    You can add 10-15% of water to lower the freeze point.
    Good to know!

    Thanks everyone!  I put the plastic gallon container in a water bath and in no time it was liquid again!
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