Glacial Acetic Acid

weedar · Wed Feb 23, 2005 7:50 pm

In a place where acetic acid isn't easily available, what would one do to
acquire or make such a chemical?

IndoleAmine · Dreamreader Deluxe

Google for "Megalomania's method" found at Sciencemadness, it uses concentrated H2SO4 to dry the aequous acetic, followed by (vacuum) distillation to separate the GAA from the H2SO4/water (wouldn't start with vinegar though; try buying at least 60%, or it is too much work).

The whole thing is very similar to a HCl/H2SO4 gas generator: The sulfuric has a greater affinity for water and binds H2O more easily. Therefore the weaker acid (HCl or GAA) becomes dried and can be separated (since GAA is no gas at rt, distillation is necessary; with HCl gas of ocurse not).

java · Consumer

How about trying to make it? .....there are some links to the synthesis , let me see if I have one, here is one making acetic acid from vinegar then drying it to make the galcial acidic acid.........java

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youngjunky
(Member)
12-04-98 02:50
No 90051

Re:acetic acid from vinegar?

my nearest source of acetic acid is about 200 miles away. got no car. iv got the recipe posted in rhodiums site but it is not a complete proceder. also did a search here but that also came up short. so here is my delema. i need to make the acetic acid ester of pseudo. can this be done just using vinegar? if not could vinegar be fractionally distilled? if not could somebody please give a little more info about the recipe on rhodiums page or just stear me in the right direction. thanks much.

Commodium
(Member)
12-04-98 11:27
No 90052

Re: acetic acid from vinegar? Bookmark

http://www.montana.com/formulary/BULK-PRC1.html

Mickey Finn
(Member)
12-07-98 08:07
No 90053
Re: acetic acid from vinegar?

Distillation of acetic acid from vinegar is not feasable because it forms an annoying azeotrope with water which prevents seperating; possibly, one could form the sodium salt from the vinegar by adding sodium hydroxide until neutral, or slightly acidic, and then evaporating. With the sodium acetate one should be able to add concentrated sulphuric acid and then distill over the mixture to obtain acetic acid. I would be interested if someone knows a better way to remove the water from vinegar as this is of interest to me as well. Thanks.

youngjunky
(Member)
12-07-98 14:55
No 90054
      Re: acetic acid from vinegar? Bookmark

MF. thanks for the info on the azetrope. i to found out about that hypothetical recipe from rhodiums page. it would be easy to do if i knew a couple of things. how much H2SO4 would i add to the sodium acetate. and what are the boiling points of acetic acid and H2SO4.
commodium. thanks for the site but in no way will i order chems to my house. for those that will this is an excellent mor many things! makes me want to go in to photograghy. you should tell more people about this site.

Mickey Finn
(Member)
12-08-98 10:08
No 90055
      Re: acetic acid from vinegar? Bookmark

The chemicals needed to do this are extremely easy to get. Vinegar, lye (red devil), and conc. sulfuric acid (super drain cleaner at Menard's or some other large building supply center --- great for getting other solvents as well, is trichloroethane (carbosol) as good as dichloromethane?)Anyway add lye dissolved in a little water (this gets hot) to vinegar until it turns lightly yellow, then add vinegar small amounts at a time until the yellow discoloration dissipates, that way you know your mixture is not basic, excess NaOH will react with the H2SO4 and one of the products of that reaction is water which we are trying to get rid of, excess vinegar will just evaporate. Then dry the solution to leave the sodium acetate. Add just enough sulfuric acid to the sodium acetate so that it dissolves, this is not too critical; however using too much acid will introduce excess water to the mix as the concentrated acid has some water About 6% allthough I don't believe that this can be driven off the acid too easily as sulfuric acid is extremely hydrophyllic (loves water). The distillation is fairly easy as the boiling points of the two liquids are well separated. Acetic acid boils at 118 C and Sulphuric acid boils at 338 C (however the dihydrate of sulfuric acid boils at 167 C but this is still a 49 degree difference which is far enough to effect a good separation by distillation. I hope that information helps.

youngjunky
(Member)
12-08-98 15:37
No 90056
      Re: acetic acid from vinegar? Bookmark

Mickey Finn thanks much. that was my last hurdle in this hypothetical thingy i would like to dream. thanks much. and yes menards is a great place for a chemhack.

Mdm. Atom
(Member)
03-07-99 16:09
No 90057
      Re: acetic acid from vinegar? Bookmark

How would the Sodium Acetate Soln.it be dried? Reflux?
Would this yield galcial?
Sure would be nice to know.
You know, for educational purposes!

Chromic
(Synaptic Self-Mutilator)
11-21-02 16:54
No 382006
      Drying acetic acid Bookmark

There is no azeotrope formed with water and acetic acid that I could find. The Perry's lists this as the data on acetic acid:
liquid vapor liquid vapor
Temp   mol frac    w/w
118.3 0 0    100.0 100.0
110.6 0.1881 0.3063    93.5   88.3
107.8 0.3084 0.4467    88.2   80.5
105.2 0.4498 0.5973    80.3   69.2
104.3 0.5195 0.658 75.5   63.4
103.5 0.5824 0.7112    70.5   57.5
102.8 0.6750 0.7797    61.6   48.5
102.1 0.7261 0.8239    55.7   41.6
101.5 0.7951 0.8671    46.2   33.8
100.8 0.8556 0.9042    36.0   26.1
100.8 0.8787 0.9186    31.5   22.8
100.5 0.9134 0.9409    24.0   17.3
100.2 0.9578 0.9708    12.8 9.1
100 1 1    0 0
The problem is that they don't separate easily. ie distilling a liquid of 88% acetic acid only gives a 93% vapor. Piss-poor separation. Fortunately if you you only need to boost the concentration 5% or so, a really long column will allow you to dry your acetic acid (ie to get the last of the water out).

lugh
(Moderator)
11-21-02 17:15
No 382017
      Industry Bookmark

As was mentioned in Post 249833 (lugh: "Study More Chemistry!!!", Chemistry Discourse), the industrial method of manufacturing glacial acetic acid uses sulfuric acid as a drying agent

Organikum
(Hive Bee)
11-21-02 18:11
No 382036
      distilling, than freezing out Bookmark

For most laboratory uses this procedure is sufficient:
- distill with a good fractionating columm, you should reach about 90% to 95%.
- freeze the acetic acid out by putting it in a freezer (not deep-freezer) and waiting until it starts solidifying. Do this in a squeezable plastic bottle as now you squeeze the slush and pour away the water. Repeat this sometimes. Done.
If your vinegar seems to be contaminated with something and for getting better results in didtillation it may be favorable to add some high boiling alcohol to the vinegar. Perhaps you loose something by an azeotrope but the middle fraction (acetic acid) will be much cleaner. As this should be be done in a big setup for making any sense I see no problem if 5 or 7 liters are procesed.
ORGY
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now or never

lugh
(Moderator)
11-22-02 13:37
No 382358
      References
(Rated as: excellent) Bookmark

A calculated amount of potassium or sodium bisulfate may bee used instead of concentrated sulfuric acid, in producing the so called "soda acid" Prior to the introduction of synthetic acetic acid, this was the most anhydrous form of glacial acetic acid available. Some patented methods of distillation are Patent DE220705, Patent US1463209, Patent FR612595, Patent FR449035 and Patent US1196329 Electrolytic purification methods can bee found in Patent US1104978 and Patent US1210792 Some methods of concentration by distillation of acetic acid are Patent GB218271, Patent GB218272, Patent FR594925, Patent GB204196, Patent GB187603, Patent US1477076, Patent GB230447, Patent GB296794, Patent GB3000923, Patent GB356741 and Patent GB298137 Some non patent references are Chem Ztg 55 881 (1931), Chem and Met Eng 36 657 (1929), Ind Eng Chem 24 722 (1932) & 23 482 (1931) and Z Agnew Chem 20 148 (1916) Concentration of acetic acid by adsorption is disclosed in Patent GB332983 and Z Physikal Chem 29 326 (1925) Removal of water by selective adsorption is patented in Patent GB314913, Patent US1492717, Patent US1492718, Patent US1817993, Patent GB338187, Patent DE230171, Patent DE282263 and Patent DE292959 Concentration of acetic acid by freezing is the subject of Patent GB378463 and Patent GB378463 Some more applicable references are Patent US2275802, JACS 54 1429 (1932), 53 2881 (1931) & 58 2585 (1936), JCS 1751 (1910) and Ind Eng Chem 20 1379 (1928) Probably the most effective drying agent available to most bees would be anhydrous copper sulfate

Chromic
(Synaptic Self-Mutilator)
11-22-02 23:11
No 382519
      Ideas Bookmark

I've spent some time looking at these patents, but I find them next to unreadable. I'm used to chem abstracts...
You mention drying agents, I don't like these ideas as they are rather messy and need to be regenerated. You mention special membranes, which sound cool, but are out of reach. Adsorption is cool, I remember how acetic acid is preferentially taken up my adsorbants like activated charcoal.
In one of the patents, using the azeotrope of trichloroethylene/dichloroethylene/etc and water is mentioned to concentrate formic, acetic and propanoic acid. IIRC, the azeotrope forms somewhere around 70C with perc. Is azeotropic distillation a reasonable way to proceed? Can you recommend it?
I didn't see any examples on mixing sulfuric acid and an acetate salt, but I imagine if mixing bisulfate with acetate will make acetic acid, only a small molar excess would be required.
Thanks!

lugh
(Moderator)
11-23-02 02:47
No 382553
      Details Bookmark

It's stated you use the calculated amount of sulfuric acid in making "soda acid"; since this was/is the traditional route from long ago, no one's going to publish it Here's the abstract from Patent GB378463
Dilute acetic acid such as vinegar is concentrated by passing the pre-cooled solution through a heat exchanger at a sufficient speed and rate of heat exchange to cause the formation of ice crystals which are carried along by the liquid stream and separated. The crystals are washed with some of the initial solution and may then be mixed with alcohol, the mixture being used to pre-cool the solution, and afterwards being returned to the vinegar plant so as to supply the alcohol and a part of the water needed for the process while saving the remaining acetic acid. In an example, the concentration of 10 per cent vinegar is effected by passing the solution, pre-cooled to -2 DEG C. through a heat exchanger at 3 feet per second, the heat transfer being 500-1000 calories per square metre of cooling surface per hour. To control or limit the rate of cooling, the cooling surfaces may be coated with material of low conductivity such as rubber or enamel. More than one heat exchanger may be used; for instance the first may cool the liquor to -5 DEG C. and the second to -15 DEG C. giving a vinegar of 40 per cent.
The eutetic point of acetic acid/water is -26°C, thus it seems clear that if one is starting with vinegar, that one combine these techniques, xylene is probably the most easily available solvent mentioned, the haloethylenes are somewhat more expensive. Azeotropic distillation has been used in industry for almost a hundred years, it's actually quite easy

callen
11-23-02 21:37
      Form the acetate
(Rated as: off-topic) Bookmark

Chromic
(Synaptic Self-Mutilator)
11-23-02 22:54
No 382735
      Thanks, but... Bookmark

Thanks, but I'm looking for downers not uppers.

El_Zorro
(Hive Addict)
11-24-02 13:07
No 382897
      Alright, I'm never using vinegar in anything I ... Bookmark

Alright, I'm never using vinegar in anything I eat again. I neutralized some distillde white vinegar with abking soda, and started boiling it down. The lower the volume got, the more it started to turn light brown. Then the solution started to give off some kind of smell. I know I've smelled it before, but I can't place it. Something to do with cooking, or cookies, or something. But then I got a pretty fucking bad headache, which pissed me off. But then I let the solution cool, and it crystallized into little rocks of sodium acetate.

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A calculated amount of potassium or sodium bisulfate may bee used instead of concentrated sulfuric acid

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Does that mean a bisulfate can be used on Na or K nitrate to get pure HNO3, too?
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It is seductive, way too seductive.    -Eleusis

Chromic
(Synaptic Self-Mutilator)
11-24-02 21:37
No 383054
      purifying dilute acetic acid Bookmark

Technique --1 - testing it out
You have to distill the vinegar to get sufficiently purified acetic acid (or purchase vinegar spirits)... otherwise you'll get the crap that the bacteria and yeast cells left behind in the fermentation process used to make vinegar (leaves black/brown crap on your flasks--perfectly safe to eat / drink, but not something you want in your sodium acetate). Slowly add baking soda (it bubbles) with a slight excess of acetic acid, then boil that down to get anhydrous sodium acetate.
The problem is then figuring out how to get back the acetic acid. I tried adding 1.25 eq of sulfuric acid, but it's not enough to even cover the sodium acetate. The reaction between sodium acetate and sulfuric acid is highly exothermic (careful!). It wasn't until 3 eq of sulfuric acid did it look possible to do.
Technique --2 - testing it out
Concentration by azeotropically removing the water with tetrachloroethylene was a failure for me. The setup I used is:
From the bottom to the top:
1) flask with 30ml perc, 150ml acetic acid & stir bar
2) vigreux column
3) claisen adapter (monitoring temperature in the center hole)
4) pressure-equalized addition funnel
5) reflux condenser
The perc and acetic acid formed two layers. Then I distilled it (the vapors were at 90C until the water was removed...) until all of the water was left in the pressure equalized addition funnel (draining out the perc on the bottom layer in the addition funnel occassionally so it could recycle). Eventually one layer was left in the flask. Unfortunately, the perc and acetic acid were miscible! Now I've got perc with acetic acid instead of water with acetic acid. Great, absolutely fucking useless... I must be missing something. I wish I was better at researching.

Chromic
(Synaptic Self-Mutilator)
11-24-02 23:29
No 383074
      Mistaken... Bookmark

It was feasible to do this with only 2 H+ eq of sulfuric acid. (ie 1 mol H2SO4 for each 1 mol NaOAc)
With external cooling, to 150g NaOAc (1.8mol) in a 500ml flask, 180g H2SO4 (3.7mol H+, 2 eq H+) was ever so slowly added. All of the solids did not dissolve. Fractional distillation with magnetic stirring was started. It was possible to distill off 85g acetic acid which is a 78% yield before the flask started to fill to the top with foam (perhaps a touch more H2SO4 would have been advisable). The distillation range was 110-120C (holding mostly around 118C). There was also some white smoke produced by the reaction (??) that was a transient phenomenon and never left the distillation setup.
Except for this reaction being so time-intensive, it's a fantastic way for over the counter glacial acetic acid.
I'd love to hear some input on how to make azeotropic distillation work though... that sounds like a far easier way to purify acetic acid.

UKBEE
(Hive Bee)
11-25-02 08:57
No 383209
      While we are on the subject Bookmark

SWIM bought some distilled white vinegar.... whats the easiest way to find out how concentrated it is ?
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I love the smell of Ketone in the morning.

Chromic
(Synaptic Self-Mutilator)
11-25-02 09:45
No 383216
      Titration Bookmark

Titrate the acetic acid with NaOH to find out what percentage it is. If you just want a rough idea, figure out how many grams of baking soda react with say 100ml of vinegar. Then work backwards from that and figure out the percentage.

Mountain_Girl
(Hive Bee)
11-25-02 23:38
No 383419
      Azeotropic drying of acetic acid Bookmark

Chromic,
Which patent out of lugh's* long list described azeotropic drying with chlorinated hydrocarbons ?
[Don't feel like going thru all of them]
Anyhow, I would say that while other combinations of acids & chlorinated hydrocarbons might work for drying, using tetrachloroethylene to dry acetic acid is no good: their bp's are too close [GAA 118°C, perc 121 °C]. So after water removal, separation of the GAA from the perc becomes a bitch. And, as can be expected from close boilers, an azeotrope is formed [61.5% GAA, bp 107°C], so adding too much perc will also be a problem.
* Patent GB2182271 must be wrong cos it describes a clamping device.
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Mountain Boy

Spacemonkey · Thu Feb 24, 2005 2:23 am

IMHO - glacial acetic acid from drying or neutralizing vinegar is a waste of time if you need more than a small amount.

I think the best method for any sort of production scale is the thermal decomposition of acetone to ketene and from that to acetic annhydride. The only downside is the toxcisity of ketene - but I don't believe that to be as big of an issue as people make it out to be if proper care is taken.

Organikum posted some excellent stuff on the matter and swim had started to construct the apparatus when he found gallons of GAA cheap and lost interest in the project.

It can also be had from the oxidation of ethanol if the oxidation agent is in excess. This is the method they used to use in industrial production if i'm not mistaken.

java · Consumer

Here is a post over at sciencemadness on the acetic anhydride synthesis that may be of assistance to you in your quest.......java

acetic anhydride

Spacemonkey · Thu Feb 24, 2005 5:22 am

Also at scimad:
Acetic Anhydride 2
http://www.sciencemadness.org/talk/viewthread.php?tid=571

Spacemonkey · Thu Feb 24, 2005 5:27 am

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.

-- a post by Hermes_Trismegistus on sciencemaddness

weedar · Thu Feb 24, 2005 9:27 pm

Thanks for all the replies, I just have to digest all the information beefore
I'm able to ask even more questions. Smile

Guest · Thu Mar 03, 2005 6:21 pm

Sodium acetate is easily made from white clear vineagar & Sodium bi-carbonate,
GAA, is easily prepared from sodium acetate and HCL, and simple distillation

I have trried this many times, and found it very easy,.

syn

Guest · Thu Mar 03, 2005 6:57 pm

sony · Thu Mar 03, 2005 9:16 pm

Why would HCl not work say HCl in dry ether for example for this procedure?

IndoleAmine · Dreamreader Deluxe

Because we're talking about making amounts of GAA, not traces.

If you use HCl for driving off the acetic from amm.acetate, you need to gas dry HCl into ether because 37%HCl contains 63% water and cannot dry anything, so you have to use gassed ether; and this is waaaaaay too much work involved, because:

.....SIMPLY DRIP 60% ACETIC (or vinegar) INTO 98% SULFURIC and you have ~98% acetic upon distillation.......
(as orgy said)

Industry does this on a millon ton scale each year....

i_a

Guest · Fri Mar 04, 2005 4:02 pm

You have to use sodium acetate and H2SO4 stronger than 94% when you want GAA, not 60% acetic acid or vinegar.

IndoleAmine · Dreamreader Deluxe

Do I really have to?

My few braincells tell me that 98% H2SO4 are quite well able to remove almost all of the 63 percent H2O present in lab grade hydrochloric, at least when you use the Vogel'smethod for a HCl gas generator (dripping HCl into H2SO4)... Rolling Eyes

(and please consider that 60% acetic has only 40% water, and acetic distills azeotropically with 5% water - HCl distills with 80% water in the azeotrope. And with HCl, H2SO4 can remove all water! Although the water content is higher than with acetic, and although the evaporation rate of water is 4 times higher than that of HCl in their azeotrope - compared to a 19x higer evaporation rate of acetic vs. water in their azeotrope...)

IndoleAmine · Dreamreader Deluxe

BTW with peracetic, this H2SO4 drying works like a charm - why should it not work with acetic (to make it simple)?

i_a