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Author: Subject: Vinegar to Glacial Acetic Acid Via Charcoal
learner
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[*] posted on 21-3-2006 at 05:48
Vinegar to Glacial Acetic Acid Via Charcoal


Trying to Find Info On Johann Tobias Lowitz's 1789 method of concentrating Dilute acetic acid by repeatedly passing over charcoal. I can find very little info other than that he obtained GAA in this manner.
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[*] posted on 21-3-2006 at 18:12


Just buy the stuff... its not worth the hassle to make it.

Find the right photo chemistry store and have them order you a coupla gallons for around $35 or so each.
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[*] posted on 21-3-2006 at 18:48


Maybe it's not worth the hassel, but maybe it would be fun? Way to shoot someone down right off the bat. Personally I would be interested in this method. But I don't get how it would work. I really don't know that much about activated carbon, 'one of nature's mysteries' I would explain if pressed but my first impression is that it would work to remove the acetic acid from the water considering it sucks up all the other oganic stuff you usually use it to get rid of. So how would it concentrate it, does it absorb water appreciably, I never noticed.



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[*] posted on 21-3-2006 at 18:48


Couldn't you distill pickeling vinegar to an extremely high concentrations of acetic acid?



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BromicAcid
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[*] posted on 21-3-2006 at 18:53


Now there is a huge thread on that somewhere around here, I think at least three pages on if you can distill OTC vinegar to get concentrated acetic acid, we got hung up on if there was an azeotrope or not and I don't know if anyone came to a consensus on the issue.



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[*] posted on 21-3-2006 at 19:38


CRC's Handbook of Chemistry and Physics lists an azeotrope of acetic acid and water as boiling at 76.6 degrees Centrigrade and being composed of 97% water and 3% acetic acid. The industrial method for the preparation of glacial acetic acid is distillation using sulfuric acid as a drying agent. An old post, unfortunately currently unavailable:


lugh
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No 382358
References
(Rated as: excellent)

A calculated amount of potassium or sodium bisulfate may bee used instead of concentrated sulfuric acid, in producing the so called "soda acid" :) Prior to the introduction of synthetic acetic acid, this was the most anhydrous form of glacial acetic acid available. Some patented methods of distillation are DE220705, US1463209, FR612595, FR449035 and US1196329 :) Electrolytic purification methods can bee found in US1104978 and US1210792 :) Some methods of concentration by distillation of acetic acid are GB218271, GB218272, FR594925, GB204196, GB187603, US1477076, GB230447, GB296794, GB3000923, GB356741 and GB298137 :) Some non patent references are Chem Ztg 55 881 (1931), Chem and Met Eng 36 657 (1929), Ind Eng Chem 24 722 (1932) & 23 482 (1931) and Z Agnew Chem 20 148 (1916) :) Concentration of acetic acid by adsorption is disclosed in GB332983 and Z Physikal Chem 29 326 (1925) :) Removal of water by selective adsorption is patented in GB314913, US1492717, US1492718, US1817993, GB338187, DE230171, DE282263 and DE292959 :) Concentration of acetic acid by freezing is the subject of GB378463 and GB378463 :) Some more applicable references are US2275802, JACS 54 1429 (1932), 53 2881 (1931) & 58 2585 (1936), JCS 1751 (1910) and Ind Eng Chem 20 1379 (1928) :) Probably the most effective drying agent available to most bees would be anhydrous copper sulfate

:D

[Edited on 22-3-2006 by leu]




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[*] posted on 21-3-2006 at 22:47


Wow, azeotrope at 97% water and 3% acetic acid? That's surprising, considering that household vinegar is already 5% acetic acid :D
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[*] posted on 22-3-2006 at 01:57


Is the real aim of the exercise then to produce acetic anhydride, for acetylation reactions on alcohols and phenols? That would involve a dehydration, probably either by reaction with acetyl choride in the presence of pyridine (which forms the hydrochloride), or by (on a solid substrate like AlPO4) dehydration at 700ºC to ketene which can then react with further acetic cid to form the anhydride.

BTW Perry's Chemical Engineers' Handbook, ch.13, does not seem to list a water-acetic acid azeotrope, although it lists a water-propionic acid one with 94.7% propionic acid.
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[*] posted on 22-3-2006 at 02:17
Desiccants


What about other desiccants ? Aren't there other materials that would be suitable in extracting
the H2O out of the mix ? I found that dried out rock salt works well in dehydrating ethanol.
Just a few thoughts.




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[*] posted on 22-3-2006 at 03:09


This azeotrope only seems to exist in certain CRC's and nowhere else. I don't think that there are any azeotrope tables in my (23rd, 1939) edition.

Simple distillation of acetic acid of any concentration gives a weaker distillate and a stronger residue, it's that simple.

Anyone with access to the RSC archive can take a look for themselves, this is the article that I referred to in the earlier thread: http://dx.doi.org/10.1039/JS8621500270
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[*] posted on 22-3-2006 at 03:20


I didn't mean to intentially shoot down learner this one, but I have BTDT. Sure it can be prepared in the lab, but it just so happens that acetic acid is one of many chemicals that for all intents and purposes is better left to large scale industrial production. The reason why is because acetic acid just totally violates the ideal gas law or whatever its called... it can be distilled feasibly, but only when there is a high enough concentration of acetic acid to begin with... all the water is azeotropically removed first leaving only pure acid remaining.

The only practical home method I used to know of for concentrating vinegar is to add in a alkaline metal carbonate, boil off the water, and then add that to concentrated sulfuric acid and distill. The catch to that is your basically exchanging one acid for another and it takes forever to boil off all the water and distill the final product.

However after looking at the US1492718 patent, I think that this might be a much more viable method. You start off with anhydrous sodium sulfate (which just happens to be cheaper than dog poop) and adding it to vinegar over 38C then cooling it to form Glauber's salt (sodium sulfate decahydrate) and filtering off the acid. That is good, because anhydrous sodium sulfate can absorb 1.2 times its own weight in water then crystalize out of solution. I also did not know this, but according to the patent, if Glauber's salt is heated above its crystalization point of 38 degrees, then supposedly near anhydrous sodium sulfate is precipitated... that means that you could simply heat things up a bit, then filter off the sodium sulfate and you would be good to go for another round saving massive amounts of time.

Still though it would require over 20 gallons of vinegar to make 1 gallon of GAA once losses are factored in and eat up a lot of time.
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[*] posted on 22-3-2006 at 05:02


What's up with all the people trying to use vinegar?
Vinegar is possibly the worst precursor to GAA you can use, with about 5% acetic acid content.

There is a product sold for descaling, cleaning and for food use (after dilution of course) that consists of 25% acetic acid and nothing else but water (it says so on the back). It carries a warning sign saying "Irritant" and "Caution: Do not consume undiluted".
It is called "Essigessenz" in germany, and the appropriate english name for it would most likely be "spirits of vinegar" or "essence of vinegar".
I use this product all the time when aqueous acetic acid is required. Perfect for making sodium acetate by adding Na2CO3, which happens to be sold as "washing soda" for about 1€ per 500g.

I have heard that a product consisting of 60% acetic acid is sold for use in commercial kitchens, though apparently it is only sold to commercial users.

If you need GAA, go to the pharmacy and let them order a liter for you. It is absolutely not worth the effort to make it yourself, even when you have 25 or 60% acetic acid.

I tried to distill the 25% AcOH through a column once, and the boiling point remained constant at 100°C. The distillate contained as much acetic acid as the residue!
I think it was due to my column being ineficient, since the liquid didn't wet the glass but condensed as small droplets inside it. I think it was contaminated with silicone oil, I heard that silicone oil does this and renders the column ineffective for fractionation of watery liquids.
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[*] posted on 22-3-2006 at 05:49


1) 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. I did not check however if the distilled water contained acetic acid because GC columns dont like water. If you have a little bit of water in acetic acid, there is no problem to remove it.

2) Darkblade48 : Household vinegar is simply made from diluting industrial glacial acetic acid which is produced by the Monsanto process consisting in the carbonylation of methanol.

3) Evil_lurker : I would be afraid that sodium sulfate would also trap the acetic acid in the crystalline clusters and you would lose a considerable amount of it.




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[*] posted on 22-3-2006 at 07:02


Re: 2) -- you sure of that? I think most products have to be as natural as possible, i.e., why they don't allow industrial ethanol in alcoholic drinks -- legally has to be fermented. Vinegar is a fermented product, too. Seems to me there's a faint odor of ethanol in vinegar, too (despite being distilled?) although I might be remembering wrong or confusing the smell.

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[*] posted on 22-3-2006 at 07:31


I would not put my hand in the fire but the Monsanto process is THE cheapest way to make bulk acetic acid. You get methanol from the water-syngas process which is a cheap process too. The fermentation process seems to be a long one which is limited by the scaleup possibility. Acetic acid is one of the most mass produced chemical in the world. You need a fast and efficient way to generate huge quantities. I would think that it is the best source to make 5% aa solution for domestic market. By the way, Eastman offers food grade, Kosher glacial acetic acid !!!

look here http://www.eastman.com/Product_Information/ProductHome.asp?P...

In the case of ethanol, there are a lot of process to make it. In alcoholic drinks, it always come from the fermentation of natural sugars which generates also other flavors along with alcohol. Making a drink with absolute ethanol and fruit juice is a anti-gastronomic way to get hungover. :o

By the way, "natural" is a very confusing word because people tends to forget that there are no differences between natural and artificial chemicals when isolated in a pure form. Fermentation produced ethanol or synthetic ethanol is the same molecule. If it is pure, there are no possible distinctions. Same thing for vanilla, vitamin C or sodium bicarbonate.




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[*] posted on 22-3-2006 at 12:10


Unfortunately here in the USA, most phamacies only carry only pre-made stuff and compounding phamacies don't want to fool around with amateur chemists. Thats the reason why ppl want to use vinegar is because it is the most readily available acetic acid source there is.... the 20%+ stuff can be fairly difficult to find and if you had to order it would cost just as much to ship as the glacial due to extra water weight.

IIRC, the clear vinegar in the stores is actually the dark stuff that has been filtered over activated charcoal to remove impurities.
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[*] posted on 22-3-2006 at 13:30


No studur, all vinegar (by definition) is made by fermentation.

[Edited on 22-3-2006 by S.C. Wack]
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[*] posted on 22-3-2006 at 13:44
SC Wack is right


SC Wack : You are right. I went on the Heinz website and they state that their distilled white vinegar comes from corn. Which is known source of ethanol.
http://www.heinz.com/jsp/consumer_faq.jsp

In wikipedia, they state another process :

Quote:
Most vinegar today is made in submerged tank culture, first described in 1949 by Otto Hromatka and Heinrich Ebner. In this method, alcohol is fermented to vinegar in a continuously stirred tank, and oxygen is supplied by bubbling air through the solution. Using this method, vinegar of 15% acetic acid can be prepared in only 2–3 days.


http://en.wikipedia.org/wiki/Acetic_acid

The Monsanto process is for the industrial glacial acetic acid




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[*] posted on 22-3-2006 at 14:38


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).




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[*] posted on 22-3-2006 at 15:59


Quote:
Originally posted by evil_lurker
You start off with anhydrous sodium sulfate (which just happens to be cheaper than dog poop) and adding it to vinegar over 38C then cooling it to form Glauber's salt (sodium sulfate decahydrate) and filtering off the acid. That is good, because anhydrous sodium sulfate can absorb 1.2 times its own weight in water then crystalize out of solution.


I once did similar thing with magnesium sulfate. It works but almost all acetic acid gets absorbed by drying agent. You probably need some special device to press acetic acid out of that powder. I did not find a way to do this. So i gave up and decided to use sulfuric acid and sodium acetate route.
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[*] posted on 22-3-2006 at 18:38


Unless one is unable to obtain GAA, there's no reason to consider purifying vinegar by such means, it's just too expensive in terms of time and energy :( 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 :o Many combinations of compounds exhibit azeotropic behavior even though Lecat or Horsley don't list them, let alone such abbreviated lists as are in the Handbooks :P According to Kushner, Tatsievskaya, Babich & Serafimov Zh Fiz Khim 40 3010 (1966); CA 66 39364b; acetic acid and water don't form an azeotrope at 50 mm Hg :cool:



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[*] posted on 22-3-2006 at 20:21


Reacting vinegar with sodium bicarbonate and boiling off the water to get sodium acetate. What does it typically look like as it boils down, It started of quite clear but as it is getting less and less it is getting darker and darker and I can't imagine it leaving white crystals of sodium acetate. The vinegar was distilled cane sugar variety, very clear, and the boiling vessel is large stainless steal pot.
Edit, its not as dark as I thought just looked dark in dark kitchen, but it is quite yellow is that normal.

[Edited on 23-3-2006 by learner]
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[*] posted on 22-3-2006 at 20:49


Are you sure of the neutrality of the solution? If the solution was acidic the steel might have been attacked slightly.



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[*] posted on 22-3-2006 at 23:34


It was neutral but has become slightly on the basic side as it has become concentrated.
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[*] posted on 23-3-2006 at 01:16


Wait, why would it be basic? What is it that have caused this increase in pH?
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