Author Topic: Acetic acid from vinegar... A better method  (Read 7689 times)

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sYnThOmAtIc

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Acetic acid from vinegar... A better method
« on: December 22, 2003, 05:00:00 AM »
I know this is something that has been discussed before, but I have never seen this method used. I got the idea after reading  the vandium peroxide post that LUGH pointed me to. The author uses an alcohol to extract hydrogen peroxide from the remaining water with use of a salt to separate them. The well known alcohol purification method as well.

For those who don't like having flasks permanetly ringed with acetate from distilling off gallons of water from sodium acetate then distilling with sulphuric acid this may hold some promise. At least for the initial concentration if not better. So I decided to try it out on a small scale with vinegar to see if this might work.

I took 10ml of 5% vinegar and added 2ml of anhydrous ipa and  couple dashes of salt(nacl) to a culture tube. I shook untill I could get as much salt in solution as possible and extracted the top layer with a syringe and put it in a metal crucible and ignited it to verify that it was the alcohol layer. After burning a brief second I blew it out and allowed it to evap a lil more and then tested the residue with ph paper. Deep red way deeper than vinegar and then decided to smell it. Whoh damn! dumb idea! Well it is VERY PNGENT and powerful shit. I do not know pure this is. Maybe up 80% or possible in the high 90% range. I added various other salts to the alcoholic mixture  to see if anymore water would separate and none did, so there is a good cance it is mostly pure AcOH???

So the next time one of you people who would rather make this stuff than buy it ry this next time it is much simpler and quicker than neutralizing with baking soda and double distilling salts. The overall idea again is to saturate the vinegal with NaCl and extract with a minimal ammount of decently dry alcohol and distill off the alcohol to leave acetic acid.

EDIT: Here is a quick follow up

I performed this as described above a total of four times and combined the alcoholic extracts with one another and into a 50ml conical flask and distilled off the alcohol leaving a small ammount of smelly residue. I scked it out and showed to be about 1.8ml on the pipet's graduations. So this is pretty efficient on the ammount obtained in such little time. Now I know that 2.0ml is pratically useless for most people, but this is scalable of course. Right now I'm extracting a 700ml portion of vinegar and will do a complete analysis to try and determine what the water content is. Though this chemical is still much more conviently purchased, but for those who got somethign laying around and can't wait to react it and need some quick HOAc then I guess thsi is about the quickest and esiest method. Making this a salt and drying then distillig over SO3 will give a rather pure glacial acetic acid.

EDIT: Oh yeah as for the anhydrous ipa... It's not actually comletely anhydrous.. Its jsut 91% thats been separated from the remaining water using NaCl, then dried ofer Anhy, MgSO4. Though plain 70-91% should work as well. You'l just need to add extra salt and shake some more once you've added that alcohol to ensure that the salt concentration is at a max to get as much of the acid as possible.

Chromic

  • Guest
Kinda nice
« Reply #1 on: December 23, 2003, 05:44:00 AM »
Yeah it's great to use a very polar solvent like IPA or ethyl acetate to extract acetic acid from vinegar. Unfortunately you will not end up with GAA, as far as I know.

Vitus_Verdegast

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Ahem...
« Reply #2 on: December 23, 2003, 08:35:00 AM »

Now I know that 2.0ml is pratically useless for most people, but this is scalable of course. Right now I'm extracting a 700ml portion of vinegar and will do a complete analysis to try and determine what the water content is.


 I hope you realize that to obtain a liter of GAA you need about 20 1L bottles of vinegar?  :)


Making this a salt and drying then distillig over SO3 will give a rather pure glacial acetic acid.


I hope you mean H2SO4..  ;)


sYnThOmAtIc

  • Guest
At least this shitty method got a post!
« Reply #3 on: December 24, 2003, 12:50:00 AM »
Yes, there was undoubtedly some water in the residual extract. After it was evaporated, there was a tiny bit of salt in the crucible. I'd say by looking at the ammount of salt, I'd guess there was probably ten percent water, maybe more maybe less I couldn't weigh it.

I'm very aware that there are only ~180ml of acetic acid in a gallon of vinegar. Though, that hasn't stopped bees from neutralizing an entire gallon, evaping a gallon of H2O off, then drying the salt, liberating the acid, etc.
It was just a reminder of a simpler method for those who might want some quick acetic acid.

I never said GAA, but a quicker route to acetic acid. I'm just saying that in the time it usually takes to obtain a salt, one could have extracted the crude acid and continue on to make it glacial. Just quicker and less of a mess.


Vitus- Why? Will SO3 react with the acid? I figured it would react with water first to make H2SO4? Am I wrong?

Oh woops!! I see the error now. I made an error up there when I edited the post. I was thingking of the sentence where I was knocking the salt and accidentally put it in the end there. I meant to say drying over another salt then distiling over SO3....

Like anhydrous MgSO4 then distilling over the trioxide. THough for all practical purposes that isn't most peoples cup of tea. Making SO3 especially for this is quite impratical and would definately lead to a purchase.

I jsut said it cause I make my own H2So4 from pool chems and I have some laying around anyway. So of course it may just be more pratical and easier to just indeed make the salt and distill over sulfuric acid., or one could simple buy it like any sane person should ;) Though it still comes up here so much.

isopropylcumshot

  • Guest
This might be a usable idea with ...
« Reply #4 on: December 27, 2003, 07:22:00 PM »
Might be a usable idea with the OTC photographic
'stop bath concentrates'  non- citric of course... these concentrates are around 25% ish.

Chewbacca

  • Guest
SO3
« Reply #5 on: January 02, 2004, 05:03:00 AM »
"Making SO3 especially for this is quite impratical and would definately lead to a purchase."

SO3 is easily created in the lab by decomposing ammonium persulfate at around 150C. ammonium persulfate is avaliable OTC at electronics stores as a circut board etching compound.


Rhodium

  • Guest
and more?
« Reply #6 on: January 03, 2004, 10:00:00 PM »
That reaction creates SO3 together with what? Please provide more details, it sounds pretty dangerous as is.


Chewbacca

  • Guest
decomp products
« Reply #7 on: January 04, 2004, 11:12:00 AM »
Upon decomposition ammonium persulfate releases sulfur oxides, nitrogen oxides and carbon monoxide. sulfur trioxide is however the chief decomposition product, by a long shot. SWIC decomposed some at home, he noticed no NOx's at all.


methymouse

  • Guest
Why?
« Reply #8 on: January 05, 2004, 11:33:00 AM »
The sodium acetate method is extremely simple, why bother with anything else?  I don't bother distilling the water; I just boil it off in a big soup pot (has the added benefit of rejuvenating my dried sinuses--lousy winter humidity).  Cleans the hell out of the pot, too.  Then distill with some dried drain opener, et voila, glacial acetic acid.  Vitus is right, though, you do need a *lot* of vinegar.  However, GAA is simply not available in my area, and with hazard shipping, the vinegar method seems to be cheaper. 

Your method sounds like a whole lot of work, considering that the sodium acetate method requires occassionally checking on a pot of boiling water.  I've made packaged soups that take more effort.


sYnThOmAtIc

  • Guest
Why?
« Reply #9 on: January 05, 2004, 12:12:00 PM »
Alot of work? Dude, all you do is take a gallon of acid add pound of salt shake, pour in some alcohol, and separate. Takes two minutes. Ramen noodles aren't even that fast!! Please explain how that is a lot of work.

You can't even neutralize the entire gallon that quick! At lest not with any carbonate bases. Which is exactly the entire point. It's a hell of alot quicker.

Ever tried to make 3l of acetic acid at home? Takes a long damn time to get rid of all that water. It is much quicker this way. I posted it to help save some bees precous time that they don't have much of..

Polverone

  • Guest
carbon monoxide?
« Reply #10 on: January 05, 2004, 11:57:00 PM »

Upon decomposition ammonium persulfate releases sulfur oxides, nitrogen oxides and carbon monoxide. sulfur trioxide is however the chief decomposition product, by a long shot. SWIC decomposed some at home, he noticed no NOx's at all.



This sounds like fun. I've always wanted a practical SO3 source. Does sodium persulfate behave similarly? And where does the carbon monoxide come from?!




methymouse

  • Guest
Salt
« Reply #11 on: January 06, 2004, 02:47:00 AM »
A pound of salt per gallon, then shaking it, then separation.  I don't know how well the layers separate, but I don't exactly have any 2L sep funnels sitting around.  I'm skeptical that this is really that practical on a large scale, though I should probably try it before speaking further.  (I'm away from my lab at the moment.)  I have tried to make GAA via direct fractional distillation (bad idea) and neutralization, and in the latter case, it took perhaps 7 hours to make 500ml.  Of course at the same time, I was able to do two other tasks; it requires almost no supervision.  If your only time burden in your lab is making GAA, then more power to you.

One could also try killing two birds with one stone--making calcium acetate and chloroform with acetone and calcium hypochlorite, though this might contaminate the finished product with HCl.  Since most of us are going to make chloroform anyway, seems like a decent use of resources.  Does anyone have any experience with this method?


sYnThOmAtIc

  • Guest
Who said anything about 2l sep funnel?
« Reply #12 on: January 08, 2004, 11:10:00 AM »
The layers don't separate! You have to use a solvent to extract the HOAc. I did this in a 500ml sep funnel. All you have to do is add a few hundread milliters at a time! The top alcoholic layer can stay in for at least 2-3 separations with fresh salt/vinegar solution. Then once you suspect that the alcohol is saturated you use fresh alcohol.


If anybody is actually to try it, I'd try something like ethyl acetate instead of alcohol. I would have done it with ethyl acetate, but didn't have any handy. I just wanted to know if it would work. Ethyl acetate should provide much better results.

I made 100ml of acid in about twenty minutes using a 500ml sep funnel. Not including the ten minutes it took to rotovap off the alcohol. Of course if one were to use a 1L+ sep funnel, you could easily process 2-3 gallons per hour or more.

I didn't say this was the only fucking way to do it and it by far the best. I'm just sharing it becasue it is a lot quicker for making lots of homemade acetic acid. If you want to mak it quicker don't wait for 2min for separation. It forms layers in a few seconds. But 3000ml x300ml portions= 10 washings x2min= 20minutes= 300ml an hour or 600ml if you don't wait 2min for each wash or 1200ml if you just wait thirty seconds which is still quite a bit of time. 

Either it will be useful or it won't!

Chewy-- Could you elaborate a lil more on that prep? It looks very enticing and a hell of a lot simpler than decomposing bisulfate salts. Seems that it would be alot quicker also with the low heat compared to teh bisulate. Just raise a 150c oil bath to a flask with salt and stirring? that simple huh? Nothing to be careful of or special steps requirements?

gsus

  • Guest
a different tack
« Reply #13 on: February 13, 2004, 08:48:00 AM »
or you could just extract w/ an ether. dont evap, just move on to the next gallon of vinegar. beware peroxides as usual, maybe AcOH inhibits? or promotes? peroxide formation. that said, neutering w/ Ca(OH)2 isnt much of a pain. just boil away in a big stock pot. As for acetate via haloform, beware unreacted OCl. that goes for you'se making formate via EtOH instead of acetone. better to make formate/chloroform via chloral but thats off-subject.

love (the drug not the emotion)




praeseodymium

  • Guest
A lot of water.
« Reply #14 on: February 14, 2004, 01:24:00 AM »
Could one avoid all that H2O by oxidising ethanol with acidified KMnO4 or similar, and then distilling off the acetic acid?


lugh

  • Guest
Acetaldehyde
« Reply #15 on: February 14, 2004, 01:42:00 AM »

Could one avoid all that H2O by oxidising ethanol with acidified KMnO4 or similar, and then distilling off the acetic acid?




You could start with

Post 435660

(lugh: "Acetaldehyde", Novel Discourse); then read the rest of the posts in that thread  ;)  You may find many more old threads with useful information, by clicking this link:

https://www.the-hive.ws/forum/search.pl?Cat=



:)




methymouse

  • Guest
I don't think so
« Reply #16 on: February 14, 2004, 07:45:00 AM »
Based on my experience, the answer is no.  First of all, the reaction between ethanol and KMnO4 is very violent, so unless you want ethanol boiling up in your face, you should buffer the solution with a whole lot of water..  Second, there is a brown precipitate which forms.  It's not MnO2--it's a much lighter brown, and turns dark at the surface upon standing.  I presume it's the relatively insoluable Mn(OAc)3, but have no way to test that.  In any case, you would need a whole lot of KMnO4 to get any appreciable quantity of AcOH.

Edit:  I should mention that I was using the ethanol as gunk to be oxidized so that I could obtain Mn2+ ions, not with the intent of making acetic acid.


sYnThOmAtIc

  • Guest
Expensive!
« Reply #17 on: February 14, 2004, 07:38:00 PM »
Making your own acetic acid from ethanol is quite expensive. By the time you buy the alcohol you could have just bought the acid. Permanganate isn't very expensive and especially if you raise "koi fish". But that is a bit extreme for homemade acid.

I don't see how this thread survived this long. Just buy the stuff!!

BTW I'm not sure how well that ethyl acetate will work. I think it forms an azeotrope with the acetic acid. Though, it shouldn't be much loss.

elfspice

  • Guest
amen to that
« Reply #18 on: February 16, 2004, 10:43:00 AM »
yeah, forgodsakes, 80% acetic acid is available at any photographic supply as stop bath (get the ones without indicators) and from that form of acetic acid i'm sure it's not hard to get to the final result (glacial) i am thinking drying and distilling, i might be wrong... actually, i don't see why that would work even with 5% acetic (ie white vinegar), all the salts added to draw out the water won't absorb the acetic acid.

Organikum

  • Guest
you are not the center of the world...
« Reply #19 on: February 16, 2004, 04:35:00 PM »
Where I live, 8% vinegar is the best you will get by now (I hope this to change to 25% soon) and at photographers supply houses you get citric acid and no acetic at all.

Dont ask me why. I can buy 98% H2SO4 as draincleaner, 30% H2O2, 33%HCl, toluene by the barrel and much much more, everything OTC but no fucking acetic acid.