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Author: Subject: Vinegar to Glacial Acetic Acid Via Charcoal
neutrino
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[*] posted on 23-3-2006 at 03:19


Any residual sodium bicarbonate would have become the slightly basic sodium carbonate. I still don't see where the impurities would come from. Such a weak base would have a hard time attacking steel.



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[*] posted on 23-3-2006 at 04:48


Yes that would explain it being basic quite well, adding a bit more vinegar(fizzing) got it back to neutral. The stainless steel pot doesn't look like it has reacted in anyway. The vinegar I started with(8litres) was distilled and very clear with that crystal clear sparkle that good clean vinegar has, it got yellower as the water boiled off and now down to 2litres has the colour of yellow printer ink in a bottle but still has that sparkle that white vinegar has and looks clean despite being yellow . I also might note that this is my second attempt, the first time I used Cleaning vinegar which is just high acetic acid content vinegar and had similar allthough darker results, but put it down to possibly the fact that I boiled it off outside on a grill over a wood fire and thought that smoke might have adulterated it. This second time Standard distilled vinegar and boiled off inside on the gas stovetop, but similar results allthough lighter. The stainless steel pot is in common for both times. I had read to do it in a glass or iron pot but having nothing that size just went with the stainless steel pot I allready had. I'll finish evapotating it tomorrow and post the colour of the crystals I end up with.

[Edited on 23-3-2006 by learner]

[Edited on 23-3-2006 by learner]
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[*] posted on 23-3-2006 at 11:12


Its probably the heat at the bottom of the pot causing slight thermal decomposition.
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[*] posted on 23-3-2006 at 12:14


Loss of residual CO2 perhaps?
Since vinegar is made from fermented stuff it's quite possible that some sugars etc get carried over in the distilled product. These would caramelise when boiled in weak base.

"Just because an azeotrope isn't listed in a particular edition of CRC or Perry's Handbook doesn't mean it can't exist in our universe". True, but that fact that someone distilled the acid to better than the reported azeotrope does and, unless I missed the point that's what this means.
"Couple months ago , I prepared about 2.3 kg of acetic acid containing about 1-2 percent water. You can distill out water over a glass helices column (1 inch wide * 6 feet tall) then distill out acetic acid. The temperature change is drastic from 100 to 115 degC when the water is gone"

(The azeotrope seems only to be listed in the older versions- I think it was a mistake and has been remove from later versions of the CRC book.)
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[*] posted on 23-3-2006 at 12:42


Whether or not there is an azeotrope was also hashed out in the 5 page thread "acetic acid/sodium hydroxide."

Here is one of my posts from that thread that may be of use:

"Vinegar at 5wt% acetic acid is 1.6 mole% in acid. According to the vapor-liquid equilibrium data I found at the library the liquid and vapor composition at this liquid concentration are very nearly equal. This I believe makes concentration of the acid by distillation impossible or at least impractical.

I also checked "Azeotropic Data" by Gmehling et al (1994). There were 52 citations! Pressures ranged from 1.07 kPa to 5864.7 kPa with 31 citations at 101.7 kPa (atmospheric pressure). All of the references indicated "none" for existence of an azeotrope.

Needless to say I'm giving up on distillation of vinegar. "

I did made some 65% acetic acid (from vinegar) via calcium acetate distillation with hydrochloric acid.




The single most important condition for a successful synthesis is good mixing - Nicodem
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[*] posted on 24-1-2019 at 21:25
@ OP


I couldn't find his books / words, but I think I've found the process.

https://www.sciencemadness.org/talk/viewthread.php?tid=10545

https://books.google.com/books?id=d8lCAAAAYAAJ&pg=PA372&...

Basically, the chemical process of adsorption was discovered by Lowitz and he went charcoal mad as a result, I would too. He found that some of the acetic acid is being absorbed into the charcoal (adsorption) where it can become much more concentrated than it can easily become in/with water. By continually dripping / soaking and swirling the vinegar over the charcoal powder (with or without distillation / heating from below causing ultimately plain water to distill over) you end up with concentrated acetic acid in the charcoal that you can extract out again with another solvent. According to the sciencemaddness link above, the concentration can go as high as maybe 30% with no distillation/heat and maybe more like 40% with distillation. Those numbers seem to be contradicted by the book I linked to above, which suggests that by alternating between freezing the high percentage vinegar and seperating the solids, then continuing to distill with more charcoal powder that GAA can indeed be obtained.

The way he (and others from the time) describe it, it sounds as if there may actually be small GAA crystals inside / with the charcoal powder..... My understanding is that if you could just get a few seed crystals, just slowly dripping regular vinegar over it will slowly build the crystal bigger.
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[*] posted on 1-2-2019 at 17:35


I was impressed by an older post. 2006..Garage Chemist:
-------------------------------------------------------------------------------------------------------------
In Germany, pharmacies only carry pre- made stuff too.
If you want a chemical, they will always have to order it for you.
The catch is that pharmacies can order it (since they are authorised to do so) and are also authorised to sell chhemicals to the public if they have no reason for being suspicious of illegal use of the chemical. The worst they can do is to decline the request.
If you are old enough and don't order stupid shit like e.g. KNO3 (no pharmacy is going to sell you that! They know exactly that most people who want chemicals are trying to make illegal fireworks) chances are good that you will get what you want.

It is advantageous to tell the pharmacy from which supplier they should order, because it can get very expensive otherwise (they don't search for the cheapest supplier).
-------------------------------------------------------------------------------------------------------

It's a big world, and regulations are wildly inconsistent.

In the U.S., ordering KNO3 in order to make fireworks, or whatever.... Would probably be considered innocuous.

Well, I checked. Pyrotechnics suppliers limit you to 1lb per year w/o a license. Other folks may be less restrictive.

GAA we can buy without restriction, but it isn't cheap.


[Edited on 2-2-2019 by zed]

[Edited on 2-2-2019 by zed]
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