zikki007
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Preparation of concentred acetic acid from sodium acetate
I had an idea for preration acetic acid from sodium acetate with using of sodium bisulfate.
So I simply tested it by mixing calculated amounts of sodium bisulfate and sodium acetate trihydrate. I puted it on heating to melt the sodium acetate
trihydrate and release water from it, so the reaction can go on.
Well I ended with very smelly dense paste, the terrible smell was proof, that acetic acid was formed in a good yield. But there was only a few ml of
free acetic acid, it was mostly in the dense paste from sodium sulfate, formed by the reaction. I realized one molecule of sodium sulfate can absorb
up to ten molecules of water - so that is the main problem I think, it simply absorbed all water from the trihydrate and it wanted to get much more
water, so as a result this dense paste was formed. I had also some caramel looking crystals in one corner, I wonder what it should be, maybe
decarboxyled sodium acetate? I don't want to do destilation, becouse I don't have it.
So my next idea is to add calculated amount of water :
CH3COONa*3H2O + 7H2O + NaHSO4 = Na2SO4*10H2O + CH3COOH
I will add that remaining 7 molecules of water, so the sodium sulfate can take it all, and I can end with good amount of acetic acid, which will have
crystals in it, so i can simply filter them out from it.
Do you think it should work?
[Edited on 18-6-2011 by zikki007]
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entropy51
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My, my. Yet another thread on making acetic acid. If you had bothered to search you would have found that panache has already posted quite a bit of
detail on this method. See this post and many others in the same thread: Quote: Originally posted by Panache  | I would appreciate it if you would post your procedure in detail then. I will quickly become a convert to your point of view if it works as well as
you imply!
I already did in a post in this thread on the previous page. Some finer detail though. Do grind the acetate and sodium hydrogen sulphate together in
stoiciometric ratios until you have a very fine intimately mixed powder that has begun to smell of acetic acid and is beginning to appear damp. The
sulphuric acid is really just to act as a solvent of sorts and as a heat transfer agent. I find it doesn't heat up the powders very much when added. I
just cover the powder with enough.
Additionally i use a vacuum, this helps enormously but it is not important whatsoever as i used to never use a vacuum. It speeds things up. i use a
stillhead vertical setup for this one. I intially have the conc sulphuric in the stilhead resovoir. that way everything can be assembled and the
sulphuric run in and the system run under reflux for a time before taking a your acetic acid. The vacuum negates the need for a drying tube however if
not running under vacuum do use a drying tube.
Is that enough detail, i only did this over the weekend so i have it fresh in my memory, previous to that i hadn't done it for some 18months.
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Yes, grasshopper, you must distill it. Attempting chemistry without distillation is pointless.
[Edited on 18-6-2011 by entropy51]
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Nicodem
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| Quote: Originally posted by zikki007 | I will add that remaining 7 molecules of water, so the sodium sulfate can take it all, and I can end with good amount of acetic acid, which will have
crystals in it, so i can simply filter them out from it.
Do you think it should work? |
Acetic acid is a liquid at standard conditions, so you will obviously need to apply distillation at one point during the work up. Compounds generally
don't just jump out of the reaction mixture, especially not if they are liquid (OK, there are exceptions, but this is not one of them). I suggest you
to invest into some glassware. Alternatively, you can first do syntheses that don't require distillation. There is a recent thread on topic.
PS: Open referenceless threads only in the Beginnings section, especially if on such a thoroughly discussed topic where it is more desirable to use
one of the existing threads for posting.
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Nicodem
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Thread Moved
19-6-2011 at 02:02 |
azo
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I don't no the freezing/ melting point but i am sure it will freeze
at around 0 deg celsius.
regards azo
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Random
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Maybe sodium sulfate decahydrate isn't soluble in concentrated acetic acid so it can be filtered off.
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