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kmno4
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I have just made simple experiment with extraction of acetic acid with DCM + MgSO4.
Titration of evaporated extract gave 95% of AcOH. Not large amount of MgSO4 was added, just to see that it works at all.
Amazing, but it really works.... 
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Sedit
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Seems like you need more MgSO4 and a trip to the freezer afterwards to get the full glory of Glacial acetic acid crystals 
70% AcOH I assume you started with correct?
And for my next trick I will be adding 800 plus some odd grams of NaOAc hydrate to Sodium Bisulfate and slowly allowing it to cool so that the Sodium
sulfate can form the decahydrate. Then I will filter and wash the precipitate with DCM and add this to the resulting solution for further drying.
Quick cheep high yielding. It go so typical hence the reason I started to look into ways to quickly oxidize EtOH to AcOH and got great results there
as well meaning soon that cheep gallon of EtOH in the store will be a cheep gallon of GAA with only a small investment in semi-reusable reagent.
[Edited on 21-11-2011 by Sedit]
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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kmno4
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Yes, it was 70% solution.
Fortunately I do not have to play with preparing of acetic acid.
In my country it is inexpensive and available without problems (including "glacial" version of course).
I was doubting that it is extractable with DCM, but indeed it is
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Sedit
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Yup, I have references in another thread around here that details that Acetic acid can be directly salted out of highly aq solutions using various
salts and liquid/liquid extraction. This is sort of a variation of that but the MgSO4 just down right drys the AcOH. Potassium Sulfate IIRC has the
highest potential in the reference to force AcOH out of the (aq) phase into the organic phase.
Its rather neat chemistry when you get down to it but if you already have concentrated AcOH like 70% then no need for all that as its best to just
dilute it with a Nonpolar solvent as you have seen and dry the mixture. It can be done neat without the DCM but the overall bulk of the MgSO4 gives to
much loss.
Glad to see my results where repeated with ease, I would have hated for this to turn into another one of the Nickle separation threads where everyone
had trouble duplicating my results 
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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Alastair
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Now thats something  You guys really diluted GAA just to try this? Seems like a
human sacrifice to me
I will surely try to get DCM but imo my country is not familiar with it (never seen it anywhere for any use, maybe only small amounts for dentistry)
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Bot0nist
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DCM is easily distilled from many common paint strippers. Look for the non-flammable kind that have a good fraction of methylene chloride in them.
Methylene chloride = dichloromethane = DCM of course.
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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Sedit
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I lost my scale so I made a quick attempt just to show its possible to get GAA without distillation I might add. I could have distilled but I did this
because I have been observing it through the various steps.
Best to just add the MgSO4, mix with DCM and heat so that the DCM and AcOH mixture comes to the top where it can be separated with ease. Distill off
the DCM and toss the remains in the freezer. The impurities will separate out. Thawing and refreezing will yield an increasingly pure product. Its not
needed as a simple distillation would be simpler but like I said I was observing and playing around as I went along. It killed any good yields but
gave me the information I needed to share so its an even trade.
You can see due to the discoloration from my H2SO4 used in the process that the AcOH moved to the DCM after the MgSO4 was added. I filtered, distilled
off the DCM, and froze the remainders where the impurities could be filtered off which you see in the third and forth pictures. It is by far the
simplest method for drying Acetic acid I have found. Trying to do it neat with a drying agent always caused to much loss. That is no longer and issue
and neither is the water that comes when MgSO4 hydrate is heated.
   
I got more photos but Im still playing with the product at the moment trying to see where I can get before I distill the AcOH so when im all done I
will post a picture of the purest GAA I can get.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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Alastair
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I finally travelled a little and bought pure GAA  I still cant find much DCM
used anywhere, i guess this way is off limits for me.
Sedit, i think you should make a new thread with your method as it deserves it for simplicity. Im still missing something. If H2SO4 was in the
mixture, how did you remove it?
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Sedit
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There might have been a little H2SO4 in the mix but I doubt it. I quickly prepared the Acetic acid using Sodium Bisulfate and NaOAc with a little
H2SO4 to get the reaction started. This was allowed to settle and then the fluids where filtered from the remaining Sodium sulfate hydrate. This was
just done to quickly prepare some (aq)AcOH and if I had my scale would have been a more complete writeup.
Any organic solvent would do as long as you have a means of separation, I use DCM due to its relatively low BP and ease of acquisition. I suspect you
are not looking hard enough for Methylene Chloride.
If one had 70% AcOH is would be very simple to Dilute it with DCM, Add MgSO4 or another drying agent until its dry and filter. Removing the DCM will
give you GAA.
Im working on the oxidation of EtOH using Nitric acid so a viable route to separation needed to be found. It will make GAA cost around 30$ a gallon or
so and cheeper following reactions.
[Edited on 22-12-2011 by Sedit]
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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MagicJigPipe
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| Quote: | | to show its possible to get GAA without distillation I might add. |
| Quote: | | Distill off the DCM |
?
Also, Sedit, where do you live again? Why can't you get better H2SO4?
"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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Sedit
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I can get better H2SO4, but at walmart is is about 10$ or so for a jug of it where the 97% clean H2SO4 I get at my local supplier is about twice that
if not more, much more then Im willing to spend when cheep H2SO4 or ultra cheep Sodium Bi-sulfate are able to do the job just as well.
I was inspired by you matter of fact, in an old thread where you and if my memory does not fail me, Madscientist discussed the financial factors that
come into play when synthing Glacial acetic acid. I have found it not only cheep but easy this way. Performing the acidic oxidation of EtOH with some
skill may yield me much closer to my ultra cheep goal then acid + NaOAc routes.
Make the (aq)AcOH using cheep acids and cold filtering and dry using DCM and MgSO4 or dehydrated Sodium Sulfate if your cheep as shit.
MJP, Yes my statements seem contridictory but understand I never distilled the AcOH, only recovered my DCM which would have been just the same as
evaporating on an open tray if one wanted to waste. I do not have the desire to waste DCM even if it is easy for me to get. It goes against my
monetary aspects of the synthesis.
[Edited on 22-12-2011 by Sedit]
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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entropy51
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If Sedit's dichloromethane extraction and MgSO4 drying method does work, it would probably be efficient to start with photographic stop bath which is
about 88% acetic acid. The stuff I buy is shipped as a consumer commodity without any hazardous material charges. It contains bromothymol blue
indicator, but this is easily removed by a quick distillation.
I would like to try Sedit's method on this material sometime soon myself.
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Sedit
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Entropy that's great to hear, its rather straight forward and works just as one would expect. The MgSO4 drys it, it just takes a lot more of it then
one normally uses to dry things. If needed you could calculate a good estimate of how much MgSO4 would be needed with ease. I'm also sure further
drying could be done using anhydrous CuSO4 if needed.
I'm going to try using a solid bed of Anhydrous MgSO4 next time so that separation is a snap.
It works as advertised I mean hell, I tossed together that Shitty AcOH and dried it to crystalline glacial acetic acid in no time. It stayed
crystalline in 60 degree weather and never thawed. That brings me to my next point, why the hell is it 60 degrees outside a couple days before
Christmas that's just messed up.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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Bot0nist
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"why the hell is it 60 degrees outside a couple days before Christmas that's just messed up." -sedit
Agree, 58F as a low here tonight. Not seasonal at all. My papavers are loving it though. Love the workup, BTW. Entropy, could you post or u2u me ur
source to 88% ORM acetic acid?
[Edited on 23-12-2011 by Bot0nist]
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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Sedit
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Rereading my post I want to make sure everyone knows what they are seeing in those pictures so there's no confusion down the line.
1: bottom layer is (aq)AcOH saturated with Sodium Sulfate, top layer is DCM.
2: Bottom layer is MgSO4, top is DCM/AcOH.
3: In the upside down flask is frozen GAA and in the bottom jar is the contaminates that was separated by what is basically cold filtering.
4:Glacial acetic acid in a filter.
Good luck, you probably will not need it as its simple but best of luck anyway. I would hate to have to end up trying to figure out how the hell
something I have been doing works again just to prove it
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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Sedit
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Acetic anhydride or what???
Um... Guys can someone help a bit and give me an explination to what I'm seeing here...
I left some Acetic acid/DCM mix over CaCl2 to dry for a couple days. When I distilled it what remained in the flask smelled a little funny. Its highly
contaminated AcOH left over after removing the DCM but this smell was odd. Almost like burnt Acetic acid if I had to describe it.
So I placed a couple small drops onto a watch glass and ignited it. It slightly burned with a faint greenish flame at the bottom. When dripped into
cold water it sank to the bottom yet created an emulsion look of sorts.
If there is any DCM left it is surely not enough to cause it to sink like this and only trace DCM at best. DCM is also not flammable.
What the hell is going on?
I'm freezing it right now and going to cold filter it as before and test the liquid portion I normally toss back into the stuff to be processed.
[Edited on 27-12-2011 by Sedit]
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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Sedit
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I have ruled out the possibility that the oily liquid is just trace DCM left over. The density of the liquid is denser the distilled H2O yet appears
less dense the a saturated Sodium sulfate/MgSO4 floating on top of the solution. I personally am at a loss as to what it can be because it does not
react with H2O the way i would expect it to. I am going to remove the acetic acid and then reflux it with a few drops of water to see if more AcOH
forms. It appears that this post is not getting any attention so i may move it to the AA preparation thread to try and get more answers.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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entropy51
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Well Sedit, if you think it's Ac2O, measure a boiling point. Ac2O clocks in at about 140 C.
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Sedit
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Im going to soon maybe even tonight. Im only getting small amounts of it off of each extractions and until the other day I never thought much of it to
be honest. I just thought it was tar but the materials I used to make the AcOH should not produce this amount of crap. It was NaOAc from instant hot
packs and Sodium Bisulfate with only a small amount of H2SO4 added to get the reaction started. It was never really heated either so there is no real
reason there should be this amount of left over organic material.
I highly doubt its Acetic anhydride but honestly im at a loss as to what it might be. I always figured it was just trace amounts of DCM left over that
was being removed when I froze the GAA and let the impurity run off. It wasn't until I set it on fire that got my mind really wondering what it could
be. I know Sodium Sulfate is a powerful dehydrating agent when cold but I just can't see it being strong enough to dehydrate AcOH. Could there be a
possibility that the DCM is aiding this some how?
When the kids go to sleep I will try to get an accurate measurement of the BP to give me a better idea what it may be.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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Sedit
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Boiling point has so far topped out at 60 degrees C, well below Acetic anhydride.
However, Due to the way it is boiling, the bumping and other factors that I have taken note of though the years I am sure that a lower Boiling point
material is being released right now and there is a higher boiling point material waiting in the midst. Since I currently have nothing small enough to
distill this minute quantity of material I will have to put on my engineers hat and get cracking on a micro distillation setup for my test tubes.
I already have something in mind and it should only take me an hour or so to rig it up so ill keep you updated.
Can DCM react with H2SO4 or Sodium Bisulfate creating some sort of substituted methane? Just curious.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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UnintentionalChaos
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Is your DCM pure or was it distilled from paint stripper containing methanol? If the latter, perhaps chloromethyl methyl ether is something to look
into.
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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Sedit
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Its distilled from paint thinner containing Toluene, MeOH, DCM and some waxes. I capture the DCM in water and wash it a couple times before drying it
and redistilling it so I doubt there is any Methanol left in the mix. Once upon a time I had trouble with Toluene coming over as well but I have found
a nice slow distillation at the end to remove the toluene from the Methylene Chloride.
I'll look into the properties of the ether because that is something that struck me about it in that it did have an almost etheral smell to it but not
quite so. Im going to distill it later and see if there is any other fractions hiding down there.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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Adas
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AFAIK, DCM is flammable. And I think this may describe the greenish colour of the flame, but I am not certainly sure.
Rest In Pieces!
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DJF90
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You best hope that its not chloromethyl methyl ether - its a potent carcinogen!! I'm a little confused as up there you say you was using CaCl2, then
you mention sodium sulfate?
| Quote: | I left some Acetic acid/DCM mix over CaCl2 to dry for a couple days.
...
I know Sodium Sulfate is a powerful dehydrating agent when cold but I just can't see it being strong enough to dehydrate AcOH.
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I know that CaCl2 can be used to form acetyl chloride from acetic anhydride, but yields are terrible and long reaction times are required. I don't
believe CaCl2 can effect the transformation of acetic acid to acetic anhydride.
Bear in mind ethyl chloride burns with a green flame. maybe DCM does too, albeit reluctantly.
[Edited on 30-12-2011 by DJF90]
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Sedit
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Iv ruled out DCM all together, it has been exposed to prolong heating long enough that any DCM left is gone. The flame isn't completely green its just
at the base of it that it shows green.
Im just going to have to distill the mixture and test it again. Its an anomaly nothing more at this point. Im just curious as to what it might be.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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