Sciencemadness Discussion Board - Preparation of acetic acid?

Preparation of acetic acid?

testimento - 21-2-2014 at 13:07

Acetic acid is not that available in pure or concentrated form and many topics seem to look for how to make or obtain it. Few methods so far:

1) OTC vinegar. Most are impure and need very energy intensive distillation for purer product. Usually 5-10% concentration. Good for technical purposes.

2) Vinegar concentration. Several methods have suggested for this. One is to use chloroform or other hydrophobic solvent and salt to drive acetic acid into solvent phase and then distill off the solvent. Requires lots of expensive solvents.

3) Decomposition of acetate. Metallic acetates tend to form GAA upon pyrolysis. Some, like sodium acetate, may need sodium bisulfate or strong acid. Laborous, and in case of acid, very expensive, but can produce high quality GAA.

4) Catalytic oxidation of acetaldehyde. This method is documented and working at least to the acetaldehyde phase. Requires somewhat sophisticated special equipment, but could be used to produce large quantities of high quality GAA. Process essentially contains dehydrogenation of ethanol upon copper at 300-600C into acetaldehyde, and oxidation of acetaldehyde into acetic acid. This process could probably be done with single catalyst run by using large excess of oxygen and much longer catalyst time.

5) Acetobacteric oxidation of ethanol. This is technically how we make moonshine, but we let it intentionally spoil with proper bacteria, which will turn the formed ethanol into acetic acid. Since the bacteria suffocates in it's own excrement in ethanol and acetic acid phases simultaneously, one would add calcium carbonate into the liquid so the formed acetic acid reacts with it to form acetates and therefore prologing the bacteric life for quite a lot. In theory this process is mix-n-go, but may encounter some problems, especially with correct bacteria.

gravityzero - 21-2-2014 at 13:18

When I see this type of post I have to ask, where do you live?
Acetic Acid is readily available in the most chemically restrictive environments including the US.

It can be had in concentrated form, from numerous distributors, and on the cheap.

You are on the right path with vinegar, but I find it hard to believe you can find any.

thebean - 21-2-2014 at 13:31

This video as well as this video should be of some use. I haven't tried it myself but it looks pretty simple and straight forward in both videos.

bfesser - 21-2-2014 at 14:12

You glossed over what is, in my view, the most important route. In my opinion, all of the other routes you have suggested are a waste of time, effort, and money.

3.5) NaC2H3O2 + H2SO4. High purity, high yield, nearly anhydrous, relatively cheap. Anhydrous sodium acetate is mixed with sulfuric acid and ethanoic acid is distilled off at atmospheric pressure. If only sodium acetate dihydrate is available, it is easily dried.

Random - 21-2-2014 at 14:27

One could probably make strong acetic acid from calcium acetate and sulfuric or phosphoric acid with no distillation.

S.C. Wack - 21-2-2014 at 14:57

It would be hilarious if someone made a gallon of pure acetaldehyde from alcohol with chromate, and then oxidized that further.

Other obviousness: ethyl acetate and the bonus ethanol.

testimento - 21-2-2014 at 23:41

The method for acetaldehyde is presented in germanic forum and it allows one to produce high quality acetaldehyde from ethanol via catalytic dehydration. Industry used acetaldehyde to produce acetic acid prior the newer processes involving pressures i'm not currently interested in repeating of. This catalyst is of particular interest because it can be used to produce acetaldehyde, acetic acid, formaldehyde, formic acid and diethyl ether and probably many more with very minor changes.

Beefie, I actually mentioned indirectly this method in No.3.

These things are not available in my country. Some shops actually sell acetic acid in glacial form, but they only sell very minor amounts like 100ml for 5 bucks and they aggressively report any larger orders to state forces. Don't ask why. Probably because explosives and drugs. My country hunts down these two a lot harsher than USSA but because this is a small and remote country nobody knows. Even concentrated sulfuric acid is available OTC but hey, it costs nearly 100 bucks a liter? I though i'm gonna puke when I actually saw that price tag. I consider everything expensive if they cost more than few bucks a kg/l except specialty chemicals, but these are just way off scale.

Because of this, and because it's a hobby, I'm interested in making things from dirt. What is the point if you just buy everything from shop and maybe have to boil something once to get things done? Maybe if you're a cookery but it's not a chem hobby then..

[Edited on 22-2-2014 by testimento]

[Edited on 22-2-2014 by testimento]

subsecret - 16-3-2014 at 09:59

Acetic acid is also produced when ethenone (H₂C=C=O reacts with water. Vogel's Practical Organic Chemistry outlines a procedure and an apparatus for the production of ethenone on page 372.

Oxirane - 6-11-2014 at 18:56

Hmm.. What about that acetobacteria? It can be found almost anywhere, like grapes.

If one makes a normal ethanol fermentation process, and when its finished it will have approx 15-17% of ethanol in it. Then there are added a source of acetobacteria, calcium carbonate equivalent to amount of acetic acid formed, and then air is bubbled with air stones and pump through it? This produces calcium acetate though.

How about oxidation of acetaldehyde? Acetaldehyde placed into insulated tank with sub-zero water in a flask and air is bubbled through it at specified rate and this vapor, which is below LEL which is 4% for acetaldehyde, is lead through copper catalysed reactor at 300-400C where it would oxidize into acetic acid and side products, which are then collected.

[Edited on 7-11-2014 by Oxirane]

UnintentionalChaos - 6-11-2014 at 19:22

Quote: Originally posted by Awesomeness

Acetic acid is also produced when ethenone (H₂C=C=O reacts with water. Vogel's Practical Organic Chemistry outlines a procedure and an apparatus for the production of ethenone on page 372.

Do you have any idea how toxic ketene is? To use it for acetic acid production is beyond inane.

subsecret - 7-11-2014 at 19:09

Well, I don't seem to be dead after testing the apparatus with my nose

CuReUS - 7-11-2014 at 21:00

Quote: Originally posted by Awesomeness

Well, I don't seem to be dead after testing the apparatus with my nose

how long have you been exposed

generally ketene ,phosgene have a latency period of 24 hours
read 2nd paragraph under summary
http://www.ncbi.nlm.nih.gov/books/NBK224928/

page 19,lines 32-36
http://books.google.co.in/books?id=DCSuU1yTE1sC&pg=PA30&...

page 193 ,under the title 3.1 Acute toxicity ,sub title inhalation
http://onlinelibrary.wiley.com/doi/10.1002/3527600418.mb4635...

page 5 ,under animal data ,single exposure
they talk about effects 3-14 days later
http://webcache.googleusercontent.com/search?q=cache:nC2hsTe...

in the same page ,on page 4 ,the 6th point -"Effects and mechanism of action" ,subtitle -human data
they say that ketene was a suspect chemical for non hodgkin's lymphoma and other types of cancer

this link might be more helpful than the above
http://books.google.co.in/books?id=y3-Ef3y53PkC&pg=PA420...

[Edited on 8-11-2014 by CuReUS]

subsecret - 8-11-2014 at 04:14

Thanks for the tips. It's been several months since the experiment, and I never had any problems.

Stupid_Noob - 8-11-2014 at 04:26

Distillation of cinnamaldehyde --> benzaldehyde + acetaldehyde...

Ethanol + hydrogen peroxide + Fe(I think) catalyst --> acetaldehyde

And IIRC acetaldehyde (ethanal) can be oxidised to acetic acid, but don't quote me...

[Edited on 11-8-2014 by Stupid_Noob]

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Metacelsus - 8-11-2014 at 05:31

Quote: Originally posted by S.C. Wack

It would be hilarious if someone made a gallon of pure acetaldehyde from alcohol with chromate, and then oxidized that further.

Acetaldehyde is much harder to get than ethanol.

S.C. Wack - 8-11-2014 at 15:43

Quote: Originally posted by testimento

4) Catalytic oxidation of acetaldehyde.

Quote: Originally posted by S.C. Wack

It would be hilarious if someone made a gallon of pure acetaldehyde from alcohol with chromate, and then oxidized that further.

Other obviousness: ethyl acetate and the bonus ethanol.

Quote: Originally posted by Cheddite Cheese

Quote: Originally posted by S.C. Wack

It would be hilarious if someone made a gallon of pure acetaldehyde from alcohol with chromate, and then oxidized that further.

Acetaldehyde is much harder to get than ethanol.

Of all the people who mention acetaldehyde in this thread, you quote me. It is amusing that you feel the need to so inform us, but unfortunately it is I who must inform you that it appears that you are the sort of person who needs a bright flashing scrolling sarcasm tag...but it wasn't sarcasm, because it would be hilarious if someone deliberately turned a gallon of carefully and tediously made acetaldehyde to acetic acid...

Stupid_Noob - 8-11-2014 at 19:14

Did any of you know that you can buy glacial acetic acid by the 5 gallon bottle at [\/]enard's?

You can also get 5lb bottles of potassium permanganate. BOTH TOTALLY OTC.

No bullshit.

Oops, I meant 1 gallon bottles of GAA.

[Edited on 11-9-2014 by Stupid_Noob]

Chemosynthesis - 8-11-2014 at 19:51

Yes

Quote: Originally posted by gravityzero

Acetic Acid is readily available in the most chemically restrictive environments including the US.

It can be had in concentrated form, from numerous distributors, and on the cheap.

Stupid_Noob - 8-11-2014 at 20:22

I guess I don't understand why anyone would make it... It's only about $30 a bottle... The KmNO4 wasn't much more than that. Why risk time and effort making something that can be bought cheaper and most likely higher purity.

Oxirane - 9-11-2014 at 02:56

It might not be about that. Acetic acid availability differs strongly on the market cap and conditions where it is used. If it has virtually no commercial use, it is not available outside chemical companies due to simple fact that nobody buys it. And very few chemcal company sells to individuals because the work needed is usually larger than the income from that small, even a single-barrel order, which is usually an absurb amount for 99% of amateur chemists. And since everyone is considered a terrorist nowadays, so be by quest, you'll get more likely a bunch of cops behind your door than a keg of GAA.

Using ketene for acetic acid production does not sound senseless at all from my point of view - in simplified terms you will only need acetone and red-hot-heated tube for pyrolysis, and an absorber and there you go. As a bonus you might also get acetic anhydride. It is toxic, hell yeah, but you will do the reaction in a closed apparatus and use proper exhaust ventilation and PPE. Actually the effort of preparing the setup itself speaks for larger amounts being produced due to long lead-in time. Same goes for acetaldehyde, formaldehyde and so on: it's just not worth making all that effort for small quantities, but if you need liters of it, there you go.

[Edited on 9-11-2014 by Oxirane]