Chemistry Forums for Students > Organic Chemistry Forum

Making glacial acetic acid

(1/1)

Limon:
Hey everyone!

I've begun to produce some acetic acid (vinegar) by culturing some mother of vinegar. I've read that, pure acetic acid can be a potent solvent, however, separating it from water is tricky, since they're both matching azeotropes and not even fractional distillation will work out.

Does anyone know of any cheap(ish) method to accomplish this? (Im not that interested in getting a very pure batch, 50% or more is good enough for me).

billnotgatez:

--- Quote from: Limon on January 26, 2021, 09:28:02 AM ---... separating it from water is tricky, since they're both matching azeotropes and not even fractional distillation will work out.

...(Im not that interested in getting a very pure batch, 50% or more is good enough for me).

--- End quote ---

This is confusing
What is the difference between azeotropes and a not pure batch

billnotgatez:
By the way from
https://www.wolframcloud.com/objects/demonstrations/SeparationOfAceticAcidFromWaterUsingEthylAcetateEntrainer-source.nb#:~:text=The%20binary%20mixture%20of%20acetic,of%20a%20severe%20tangent%20pinch.


The binary mixture of acetic acid and water does not form an azeotrope. Despite this, obtaining pure acetic acid (with boiling point 118.1 °C) from a solution of acetic acid and water by distillation is very difficult because of the presence of a severe tangent pinch.

billnotgatez:
Sometimes I wonder

I look up Azeotrope in WIKI and find this

https://en.wikipedia.org/wiki/Azeotrope#Zeotropy

--- Quote ---Zeotropy[edit]
Combinations of solvents that do not form an azeotrope when mixed in any proportion are said to be zeotropic. Azeotropes are useful in separating zeotropic mixtures. An example is acetic acid and water, which do not form an azeotrope. Despite this, it is very difficult to separate pure acetic acid (boiling point: 118.1 °C) from a solution of acetic acid and water by distillation alone. As progressive distillations produce solutions with less and less water, each further distillation becomes less effective at removing the remaining water. Distilling the solution to dry acetic acid is therefore economically impractical. But ethyl acetate forms an azeotrope with water that boils at 70.4 °C. By adding ethyl acetate as an entrainer, it is possible to distill away the azeotrope and leave nearly pure acetic acid as the residue.
--- End quote ---

I look up Zeotropy in WIKI
https://en.wikipedia.org/wiki/Zeotropic_mixture
and there is no mention of acetic acid

I look up Acetic acid in WIKI
https://en.wikipedia.org/wiki/Acetic_acid
and there is no mention of Zeotropy


As an aside
there is Azeotrope tables in WIKI
https://en.wikipedia.org/wiki/Azeotrope_tables
that lists

--- Quote ---acetic acid 118.1C No azeotrope

--- End quote ---

Navigation

[0] Message Index