[zuriel]

Hi folks,

Just wondering has anyone here experience/suggestions on how to dry bulk acetic acid?

[discodermolide]

What do you mean by bulk acetic acid?

[discodermolide]

In the chemist's companion, it says use triacetyl borate, form boric acid and acetic anhydride (1:5) at 60°C.
Cool and filter to get crystals.
Add crystals to acetic acid and heat. Guestimate the amount of water and add 2 to 3 times the amount of triacetylborate with respect to water and then distill the acid.

[clarkstill]

Armarego and Chai says:

"Usual impurities are traces of acetaldehyde and other oxidisable substances and water. (Glacial
acetic acid is very hygroscopic. The presence of 0.1% water lowers its m by 0.2O.) Purified by adding some
acetic anhydride to react with water present, heating for lh to just below boiling in the presence of 2g CrO3 per
lOOmL and then fractionally distilling [Orton and Bradfield J Chem SOC 960 1924,983 1927. Instead of CrO3,
2-5% (w/w) of KMn04, with boiling under reflux for 2-6h, has been used.
Traces of water have been removed by refluxing with tetraacetyl diborate (prepared by warming 1 part of boric
acid with 5 parts (w/w) of acetic anhydride at 600, cooling, and filtering off), followed by distn [Eichelberger and
La Mer J Am Chem Soc 55 3633 19331.
Refluxing with acetic anhydride in the presence of 0.2g % of 2-naphthalenesulfonic acid as catalyst has also been
used [Orton and Bradfield J Chem Soc 983 1927. Other suitable drying agents include CuSO4 and chromium
triacetate: P2O5 converts some acetic acid to the anhydride. Azeotropic removal of water by distn with
thiophene-free *benzene or with butyl acetate has been used [Birdwhistell and Griswold J Am Chem Soc 77 873
1953. An alternative purification uses fractional freezing.
Rapid procedure: Add 5% acetic anhydride, and 2% of CrO3. Reflux and fractionally distil.'