Name: Javier A.
Why does the Glacial Acetic Acid is called like that? (The GLACIAL terminology is the
This is a quote from the referenced web site below. It could be fact or fiction. I do
not know. But I always wondered that too so here is our answer. Everything in quotes
below was a direct copy from the URL below:
"Synthesis: Acetic acid is available as an OTC chemical in the form of vinegar, a
dilute solution of acetic acid. Vinegar should be available from any grocery story in
3%-5% concentrations or so. Acetic acid is a chemical that I consider to plentiful to
bother synthesizing yourself since it is a cheap, abundant OTC chemical. It can be done,
and it may be cheaper in the long run to make it on your own, but I do not have the
information handy. A trip to the library, or a web search will yield much info on the
topic. Acetic acid is more useful in concentrated, or glacial, form. Only acetic acid is
referred to as glacial rather than concentrated acid. This is because the ancients liked
how much frozen acetic acid looked, it reminded them of an ice glacier, so the term
glacial stuck. Glacial acetic acid is very corrosive and slightly flammable."
** Scroll down to 'acetic acid' **
(Glacial) 99.8 % minimum acetic acid has a rather high freezing point ==> 16.6 C. When
frozen, it looks quite like ice crystals. Thus, the term, "glacial."
Pure 100% acetic acid is sometimes called glacial acetic because when cold, it will
solidify into layered crystals similar in appearance to a glacier. I hope this answers
Good question, I do not really know. But 100% acetic acid melts at 16.7 C = 62 F. I
suspect that once upon a time when labs were not well heated that acetic acid crystallized
when the temperature was low. Acetic anhydride melts at -73 C. Since the freezing point of
water is 0 C. then slightly "wet" pure acetic acid would crystallize the pure acetic acid
(i.e. "glacial" acetic)
leaving the water in the liquid phase or the acetic anhydride also in the liquid phase. If
the crystallized acetic were separated from the liquid it would be purified. So I am
guessing the tag "glacial" referred to acetic acid that had been purified of residual water
or acetic anhydride.
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Update: June 2012