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evil_lurker
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Glacial acetic acid...
I'm working on a way to get as close to pure acetic acid without having to order it and pay those outrageous hazmat fees.
I know that you can reduce vinegar down to sodium acetate, and mix it with 98% sulfuric acid and get a finished product close to glacial.
However, that is another acid that is hard to come by in high purity, again without paying those ridiculous hazmat fees. I know I can get the stuff as
drain opener, but most brands are only 93% and/or contain numerous buffers that would hinder the process.
I was thinking that I could take the sodium acetate and mix it with some store bought concentrated hydrochloric acid then filter out the salt.
I realize that the potential end product will be far from glacial, but mainly I want to know if the NaOAc will react with the HCI.
Is this doable?
[Edited on 7-7-2005 by evil_lurker]
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Twospoons
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In New Zealand glacial acetic is available OTC from pharmacies. Where are you?
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Magpie
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Yes, it is doable with HCl. I bought some muriatic acid specifically for that purpose. Did you search and read the postings? I believe this is also
covered under Muspratt IIRC.
The single most important condition for a successful synthesis is good mixing - Nicodem
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Simon
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Some photographic shops sell acetic acid at, IIRC, ~900g/L as stop bath. (NB some shops also sell something called "odourless stop".
Obviously this isn't concentrated acetic acid  )
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kclo4
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you could buy some NaHSO4 (sodium bisulfate) and add it to your sodium acetate and distill of the acetic acid. you can get NaHSO4 from Walmart as PH
down in the pool supplies
i don't know how well it would work but because i have not ever tried it but i plan to in the future when i get a distiller. does any one know
how good the yields would be?
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neutrino
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If you live near a pool store, you can probably get sodium bisulfate (NaHSO<sub>4</sub> cheaply. Reflux with sodium acetate and you get GAA:
NaHSO<sub>4</sub> + NaC<sub>2</sub>H<sub>3</sub>O<sub>2</sub> <-->
Na<sub>2</sub>SO<sub>4</sub> + C<sub>2</sub>H<sub>4</sub>O<sub>2</sub>
This equilibrium is driven to the right by your acetic acid boiling off. This was described in another thread here somewhere.
edit: I posted at the same time as kclo4. These subscipts take too long...
[Edited on 8-7-2005 by neutrino]
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chromium
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I do not belive that 93% sulfuric does not give glacial acetic acid when sodium acetate is distilled with it. I think that buffers too cannot stop it
doing so. You should at least try.
Another way is to make it from some vinegar by freesing. Does anyone know what temperature is needed to freese it out from 30% or 10% acetic acid? Is
it possible at all? ( i have tried this @ -10C with no results )
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Magpie
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Check out the "Acetic acid/ sodium hydroxide" thread. Most of this has already been hashed out there.
The single most important condition for a successful synthesis is good mixing - Nicodem
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jimwig
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this is so obvious but i had to say it
i went to a photo supply specialist and there on the shelf were $20 gallons of glacial acetic acid.
does New Zealand have these. it is a photo chemical used to make stop bath.
which is used in goth film and paper chemistry processing to stop the action of the alkaline developers.
try these places.
btw NZ is supposed one of the most beautiful places on Earth - z'that so?
jim
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16MillionEyes
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And where do you live? I'd like to know what store you can find this from.
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evil_lurker
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Well its been a long time since 2005 and I've significantly broadened my horizons.
That said, this is the place to get your glacial acetic acid:
www.hvchemical.com
Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in
beer.
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organometallic
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Is it not possible to fractionally distill or vacuum distill acetic acid from vinegar?
In vials of ivory and coloured glass
Unstoppered, lurked her strange synthetic perfumes,
Unguent, powdered, or liquid - troubled, confused
And drowned the sense in odours.
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Magpie
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Here's a long thread on the topic:
http://www.sciencemadness.org/talk/viewthread.php?tid=2194&a...
The single most important condition for a successful synthesis is good mixing - Nicodem
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evil_lurker
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No.
The acetic acid will form an azeotrope that is just about impossible to break.
The only practical means would be to neutralize the acid with a salt, boil off the water, and add to another acid such as sulfuric and distill.
Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in
beer.
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12AX7
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Isn't the azeotrope at like, 4%, but after that, the seperation between H2O and AcOH is really bad?
Tim
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chromium
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As far as i know there is no azeotrope with acetic acid and water, just evaporation rates are almost equal. It'is quite possible to make GAA by
distillation but you need good hempel column and have to collect maybe only one drop of distillate per minute - or great part of acetic acid comes
over along with H2O.
It is even possible to just boil out water from acetic acid but almost all acetic acid evaporates along with it. Long time ago i did some experiments
with 30% acetic acid. I boiled it until volume decreased to about 1/10th of original volume. IIRC titration showed that residue was 58% AA.
Acetic acid is good example that rule of thumb which tells that remarakble differences in boiling points ensure easy separation, does not always hold.
When all think alike, then no one is thinking. - Walter Lippmann
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16MillionEyes
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I don't remember well where I read this from but you can heat sodium acetate to decomposition giving off acetic acid. Never tried it nor I know if it
works for sure. I don't know how this reaction actually works or what byproducts it gives.
The following section from an MSDS also seems to suggest this reaction does occur:
"Unusual Fire or Explosion Hazard:
THERMAL DECOMPOSITION MAY PRODUCE ACRID SMOKE AND IRRITATING FUMES." (http://www.sefsc.noaa.gov/HTMLdocs/SodiumAcetate.htm)
Also, in this other MSDS clearly states the production of the acetic acid (http://www.ambion.com/techlib/msds/msds_9740.pdf)
Perhaps the reaction goes as follows:
2NaCH3COO ---> CH3COOH + H2O + 2C + Na2O
Any ideas?
[Edited on 25-7-2007 by __________]
[Edited on 25-7-2007 by __________]
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chromium
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| Quote: | Originally posted by __________
I don't remember well where I read this from but you can heat sodium acetate to decomposition giving off acetic acid. Never tried it nor I know if it
works for sure. I don't know how this reaction actually works or what byproducts it gives.
The following section from an MSDS also seems to suggest this reaction does occur:
"Unusual Fire or Explosion Hazard:
THERMAL DECOMPOSITION MAY PRODUCE ACRID SMOKE AND IRRITATING FUMES." (http://www.sefsc.noaa.gov/HTMLdocs/SodiumAcetate.htm)
Also, in this other MSDS clearly states the production of the acetic acid (http://www.ambion.com/techlib/msds/msds_9740.pdf)
Perhaps the reaction goes as follows:
2NaCH3COO ---> CH3COOH + H2O + 2C + Na2O
Any ideas?
[Edited on 25-7-2007 by __________]
[Edited on 25-7-2007 by __________] |
This does not work. Acetates yield acetone on pyrolysis but if i recall correctly sodium acetate complexes with acetic acid and it is somehaw possible
to precipitate this complex. It decomposes on mild heating giving some acetic acid.
When all think alike, then no one is thinking. - Walter Lippmann
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chemrox
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I just posted this in another thread. I shan't retype the citation. For homebake I'd go the benzene/butyl acetate route or maybe try CuSO4 by
itself.
[Edited on 25-7-2007 by chemrox]
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16MillionEyes
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So how would the chemical equation for that reaction go? Besides, why would the last MSDS list "acetic acid" as one of the decomposition products if
it supposedly doesn't do it?
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not_important
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Thermal decomposition of acetates tends to be messy, especially if it is a hydrated salt.
Sodium acetate gives a mixture of stuff, including some acetic acid, methane, acetone, diacetyl, and others. Calcium acetate gives mostly acetone,
but other products as well. Some of the heavy metal acetates will yield a fair amount of acetic acid or (apparently, haven't tried) acetic anhydride.
Just being listed as a decomposition product doesn't mean you'll get a decent yield, or that the products will be easy to separate in pure form.
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16MillionEyes
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Never said they would but saying it will be a low yield is different to "it does not work".
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Pixicious
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Here is a method if you have access to Sulphuric Acid.
NH4Cl + NaOH -> NaCl + NH3 + H2O
You have your salt if you boil away the water.
H2SO4 + NaCl -> Na2SO4 + HCl
Mix the HCl gas with water. Put it aside, you can use it later.
CH3COOH + NaHCO3 -> CO2 + H2O + CH3COONa
Add an slight excess of Vinegar. Boil to but not beyond 320oC. The Sodium Acetate will decompose. The remaining solution if using Tesco's Value
Vinegar is a guey mess (Ammonia Caramel) and a white powder. Cook in an oven at 103oC, chop and grind the powder.
HCl + CH3COONa -> CH3COOH + NaCl + H2O
Use an excess of Sodium Acetate, filter and dry distill.
I haven't tried the last step, I still have Sodium Acetate sitting in my room. I haven't had any time to make any new Sulphuric acid.
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MagicJigPipe
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I have some excess sodium acetate so I'm going to get some bisulfate today and try that method. Many pictures will hopefully insue. Will this thread
be the right place to post a "write-up"?
Also, in my area, 90% of the photographers and photographic stores that I called just straight up said "No!" when I asked for GAA. The other ones
gave an explanation of why I shouldn't use it and/or referred me to a place that had 28% acetic acid for an outrageous price.
"You want what!??", "You don't want to use that, it stinks up the whole place and it burns your skin and nostrils.", "Nobody uses that anymore".
A couple didn't even know what it was.
This chemophobic society is truly pathetic.
"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any
question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and
that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think,
free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
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len1
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Ive tried this, its not really worthwhile because
1) vinegar contains very little CH3COOH, theres a lot of water to be boiled
2) It contains other rubbish such as sugar, which yield acrolein and other unpleasant stuff which foul when you distill the acetic off H2SO4. The
sugar i very hard to be rid off
Using HCl instead of H2SO4 will lead to a huge Cl- content
Using NaHSO4 will lead to excessive decompoition of the acetate and other products
Haloform with acetone is far more economical
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