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guaguanco
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| Quote: | Originally posted by unionised
My (1991) edition still says it doesn't.
Old CRC good; new CRC better (because they have removed some of the mistakes).
It doesn't matter how many times you check it if it's wrong.
Has anyone out there got a still, a thermometer and some vinegar? That way we can get can experimental verification one way or the other.
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Interesting. I have always heard it forms an azeotrope! In fact, I thought that was how 'distilled white vinegar' is formed. Odd that it
took so long to overturn; I'd still like to read something that definitively settles the issue...
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Hermes_Trismegistus
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acetic acid production
Acetic acid, CH3COOH, is a colourless, waterlike liquid that has a piercingly sharp, vinegary odour and a burning taste, vinegar is its dilute aqueous
sol'n and was used in the earliest languages of antiquity. Theophrastus (372-287 BC) presented a definitive study of vinegar's use in the
production of white lead and verdigris manufacture. His work was closely followed by the encyclopediast Pliny(23-79 AD).
The term "Acetic Acid" was first coined by Libavious (1540-1600 BC). Many attempts to prepare "icy" acetic acid by repeated
distillation were made, but the subsequent failures prompted Lavoisier to make a distinction between "acetous and acetic acid". Shortly
after Lavoisier's death, the connection was proven by Adet and others. Final proof was obtained when Kolbe first prepared acetic acid from its
elements in 1847.
Acetic acid (glacial) is commonly prepared from the distillation of wood in the Soviet Union, however only the credits from the distillation
byproducts makes this process economic, one can imagine that the byproducts must be so great as to make this an entirely impractical process for the
amateur chemist.
The historical preperation of acetic acid by dry distillation of metal acetate salts seems most practical. Many acetate salts are commonly available
OTC. The most common of which is sodium acetate. If one wanted to prepare acetic acid from common household vinegar, the logical step would be to
prepare an acetate salt of a commonly available powdered metal (like copper), react with the vinegar to form the corresponding acetate, evaporate the
excess water, dry the salt, and then dry distill (decompose) to form the concetrated acid. The powdered metal could probably be reused indefinitely.
Much thanks to the Kirk-Othmer encyclopedia of chemical technology, third edition.
Arguing on the internet is like running in the special olympics; even if you win: you\'re still retarded.
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Mumbles
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The heating of the salt can also form Acetone. Calcium Acetate specifically comes to mind. I don't know exactly what happens with +1 metal ions
or transition elements. The Hydroxide and Ketene might be possible. Well, the formula works anyway. I've always been under the impression that
to go from metal salt to coresponding acid you needed to add another strong acid and distill/precipitate/filter whatever the case may be.
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KABOOOM(pyrojustforfun)
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copper acetate monohydrate melts @ 115°C and decomposes @ 240°C. I couldn't find at which T it loses its water but it certainly much lower than
its dec T. maybe by destructive distilling you first collect water and then acetic anhydride which react ...
so MAYBE:
Cu(OOCCH<sub>3</sub> <sub>2</sub>.H<sub>2</sub>O
<s> ></s> Cu(OOCCH<sub>3</sub><sub>2</sub> + H<sub>2</sub>O
Cu(OOCCH<sub>3</sub><sub>2</sub>
<s> ></s> CuO + (CH<sub>3</sub>CO)<sub>2</sub>O( )
(CH<sub>3</sub>CO)<sub>2</sub>O + H<sub>2</sub>O <s> ></s>
2CH<sub>3</sub>COOH
wow if this really makes acetic anhydride it'll be one of the best methods (requires low temps, is simple and recyclable)
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Theoretic
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Maybe it will form acetone and copper carbonate (like the calcium salt) and then the carbonate will decompose. I hope this happens at lower
temperatures than with calcium acetate, would be a very nice acetone production!
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Chemtastic
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Acetic Acid
Can vinegar (5% acetic acid) be distilled to 100% glacial acetic acid, or is there an acetic acid-water azeotrope? I haven't found anything on
such an azeotrope, so I'd appreciate any information anyone might have.
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BromicAcid
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There may or may not be an azeotrope, it was the subject of discussion in this thread.
[Edited on 6/20/2004 by BromicAcid]
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S.C. Wack
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Chemists who have been dead for almost a hundred years say that acetic acid of any strength can give some glacial acid on distillation. You'll
need a lot of it, because some of it will distill before you get to that point. The old references all point to Henry Enfield Roscoe and a J. Chem.
Soc. article of his. Note that I said glacial and not 100%.
Given the energy needed, and the ease of other methods, this is not done, and I guess that it never was, industrially. Thus little info.
Finally took a minute (literally) to go to rsc.org to find the vol/page of the mentioned article: Roscoe, JCS, 15, 270-276 (1862)
[Edited on 21-6-2004 by S.C. Wack]
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tom haggen
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I'm going to try and concentrate acetic acid at very low temperatures and see if that works. Kind of like how some people say they concentrate
H2O2. I just haven't gotten around to it yet.
N/A
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thunderfvck
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Acetic acid boils pretty close to water, no? Like, a 15 degree difference...I don't know if that will make a difference, but perhaps your boiling
water vapour would be tainted with acetic acid...
I always thought that it was better to form sodium acetate and then collect this salt and react it with H2SO4 while heating and collecting the acetic
acid that boils off..
There must be better ways.
Even hydrolysing aspirin gives off acetic acid, and maybe that would be cheaper and more efficient for you...
Anyways, haven't put a lot of effort into making this chemical so I suggest you check out that thread..
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Esplosivo
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Glacial acetic acid (which is of very high conc, ie 99.8% - nothing is ever 100%  ) has a boiling point of approx 118 deg celcius. The solution of the ethanoic acid in water as found in vinegar assumes the physical properties of
water, such that the boiling point falls to 100 deg celcius. I think the best method if one wants to produce conc. ethanoic acid is either oxidation
of conc. ethanol with KMnO4/H+ or else the method mentioned by thunderfvck which I think is best:
| Quote: |
I always thought that it was better to form sodium acetate and then collect this salt and react it with H2SO4 while heating and collecting the acetic
acid that boils off..
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Theory guides, experiment decides.
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Chemtastic
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Will only H2SO4 work properly here, or will other acids work too?
2NaC2H3O2 + H2SO4 --> 2HC2H3O2 + Na2SO4, right?
So, NaC2H3O2 + HCl --> HC2H3O2 + NaCl?
On a sidenote:
For the production of sodium acetate, an excess of vinegar is better than an excess of baking soda, right? The vinegar remaining after all baking
soda is gone should just boil off...
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vulture
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Please search before posting & continue the discussion in the existing threads.
I'm merging them.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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darkflame89
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acetic acid and sodium hydroxide could be produced via electrolysis if you had all the time in the world and quick electricity at your disposal..
Just dump the salt into 2 bowl, dissolve them, get a salt brodge to connect the two bowls. Then, insert graphite rod to each of the bowl. You might
get acid at the anode, and the hydroxide in question at the cathode. But like i said, you need lots of electricity to use, and you might have to
electrolyse a few days..
Ignis ubique latet, naturam amplectitur omnem.
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TheBear
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I had one of those moments today, maybe it's genious or perhaps it's just stupid:
Anhydrous citric acid melt at 153°C and decomposes below its boiling point at 175°C. Acetic acid boils at 118°C.
Citric acids pKa's:
pKa1
3.15
pKa2
4.77
pKa3
5.19
Acetic acid's pKa: 4.78
What about mixing anhydous NaOOCCH3 and citric acid and heating to ~160°C and then condense the CH3COOH?
Is this method possible? If so: is citric acid bought in food stores anhydous (I'm guessing it's the monohydrate).
[Edited on 1-7-2004 by TheBear]
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TheBear
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Had another thought:
What about using ammonium acetate which has a melting point of 114C? Heating NH4OOCCH3 together with stochiometric amount of citric acid? If noone can
see any problems with this procedure I will try to make some glacial acetic acid with it soon.
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unionised
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You might start to produce acetamide.
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Mumbles
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If you use acetic acid you will definatly produce acetamide. What you are describing is almost a direct excerpt from Vogel. Check out page 401. The
only thing different is the reaction time. You might not allow for the full conversion with your time.
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TheBear
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Ahh I see.. Well when I want acetamid I will try that.. but for now: glacial acetic acid is the goal!
So I have to get rid of the ammonium ion, what about Cu(OOCCH3)2 which has a melting point of 115C, which is bellow the melting point of citric acid.
Or will the CuAc2 start evolving CO(CH3)2? Can't find any information on this point, it was however mentioned somewhere on this board.
(Hope citric acid works for this reaction and won't decompose)
Offtopic: This experiment has been delayed due to construction of a new fume hood.
[Edited on 14-7-2004 by TheBear]
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The_Davster
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from; Textbook of organic chemistry, Noller, 1958
...4-10% of acetic acid which may be recovered by neutralizing with lime and distilling to dryness. The gray acetate of lime so obtained may be
converted to glacial acetic acid by concentrated sulfuric acid. In recent years acetic acid has been removed from dilute aqueous solutions by
extraction from the vapor state with tar oil(Suida process), and by azeotropic distillationusing ethylene chloride, propyl acetate, or butyl acetate
to form a constant boiling mixture with the water(Clarke-Othmer process). It may be recovered as ethyl acetate by esterfying with ethyl
alcohol."
[Edited on 17-7-2004 by rogue chemist]
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Magpie
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Ca(CH2COOH)2 route to glacial acetic acid
This looks like a really straigtforward and cheap way to make glacial acid. I can hardly wait to try it. As Mendeleev has stated "sulfuric acid
is just so damn useful." It should be the right of every citizen to bear H2SO4.
The single most important condition for a successful synthesis is good mixing - Nicodem
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The_Davster
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No, Magpie, It should be the patriotic Duty of every citizen to bear H2SO4.
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unionised
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Magpie, I'm pleased to see you like the method based on Ca acetate. Did anyone like it back in January?
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Magpie
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credit where credit is due
unionized,
You don't let me get away with anything!
Yes, I do remember that you suggested the acetate method some time ago. I liked it then too. I like your freezing method also.
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Cyrus
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No Title
I tried freezing 5%ethanoic acid- (sounds much better than vinegar) The whole thing froze into a solid mass. Hmm.
I made some sodium acetate (guess how)and boiled it down to dryness in an iron
pot. I will try adding H2SO4 and distilling. My concern is that sodium acetate is efflorescent. Anyone know how much sodium acetate is lost when
boiling it down? Anyways, I love the smell of the process, a cross between freshly baked bread and vinegar. 
Calcium acetate doesn't have the same problem, I might try that.
[Edited on 18-7-2004 by Cyrus]
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