Author Topic: Glacial acetic acid from aq solutions (Read 779 times)

Sedit · « **Reply #40 on:** November 27, 2010, 03:44:52 AM »

Quote from: Sedit on June 11, 2010, 04:34:12 PM

Running 2500ml of 5% AcOH with 250ml of 70% IpOH. Using MgSO4 to saturate the solution but having issues doing so.

After review I must quote myself to explain something so perhaps you can explain something to me.

I saturated a gallon of distilled white vineger with MgSO₄ and added IpOH until phase seperation. I got seperation then it vanished. This made no sense to me at all. So I begun adding NaCl since I was out of MgSO₄ at that point and never got seperation of the IpOH phases again.

Why is this?

Second question after a few days a fine precipitate begun to form, WTF is this. I still have this gallon sitting there unable to figure out what to do with it. Could it be some sort of adduct or acetate? Sooner or later im going to filter it and titrate the solution to see if any AcOH is missing somewhere but it is a strange experiment. It still smells of IpOH and AcOH but is there a reason that MgSO₄ and NaCl can't exist together in solution?

I wish more work was put into this feild because GAA is more valuable then any reagent I can think of yet everyone seems content with either buying it or doing shitty NaAc/H₂SO₄ distillations and this is only good for very small amounts and sooner or later you can't buy it mark my words.

Sedit · « **Reply #41 on:** November 27, 2010, 03:48:56 AM »

So with that in mind lets explore our options.

NaAc+H₂SO₄
This uses alot of Sulfuric acid which isn't really cheep and for some hard to find. Not to mention there are many other better uses for Sulfuric acid then GAA production since it never seems to produce good anhydrous acetic acid on the first run.

NaAc+NaH[/sub]SO₄
Dry distillation of the two salts seems ideal until put into practice on a larger scale and over 100ml of product you end up with alot of localized overheating contaminating your product with SO₂ stinking up shit and lowering yeilds.

EtOH+Oxidant
Many sub reactions possible such as permagnate, nitric acid, vapor phase and quite possible the most viable means to alot of GAA aside from,

Ketene
Excessive equipment needed to be made just right in order to not blow yourself up or poison yourself. If done right then you have the most viable route to making gallons of GAA or Acetic Anhydride as an added bonus. By far the cheepest route around but total mastery of the process must be accomplished before even attempting it because fire or death becomes a great possibility if one is not 110% sure of what they are doing or if there equipment fails.
H₂SO₄

Lets make this happen folks its legal and its something that our minds should be able to make for pennys on the gallon yet everyone seems more concerned with meth production then they do something useful. So What do you got, lets oxidise EtOH and I will work on getting it out of any solution pure as hell. If anyone can figure out how to turn Ethylacetate into Acetic acid and EtOH then one should be able to absorb the EtOH in a mol sieve and yeild gallons of cheep OTC GAA.

atara · « **Reply #42 on:** November 28, 2010, 02:08:31 AM »

An interesting route proceeds through S2Cl2:

AcONa + S2Cl2 + heat --> SO2 + NaCl + Ac2O (acetic anhydride)

http://www.erowid.org/archive/rhodium/chemistry/anhydrides.html

Quote

Prepare 100g freshly fused NaOAc and 65g S2Cl2. A small quantity of NaOAc is placed in a thin-walled glass cooled in an ice bath. To this is added some sulfur chloride, the mixtr is vigorously stirred w/a wooden spatula, not allowing the temp to rise. Then some NaOAc is added again, and the process is repeated several times until all is mixed in. The semi-liquid mass is transferred into a 1 liter RBF. The previous operation is repeated 4 times, so that 400g NaOAc and 260 g S2Cl2 total are taken into work. The RBF is then equipped w/a reflux condenser and gently heated on a water bath to ~80-85°C. As soon as the rxn starts, the heating is removed, and in case the rxn gets too vigorous it's cooled w/cold water. After 20-30 min SO2 evolution ceases and the mixture is heated for 10 more min's on a boiling water bath. The rxn product is then distilled off under vacuum, then fractionally re-distilled at ordinary pressure, collecting the fraction boiling between 132-142°C.

Acetic anhydride can bee used to generate an arbitrary amount of GAA. The sticking point is S2Cl2; chlorine is a difficult chemical to work with.

Another route proceeds through the BV-oxidation of acetone:

acetone + hydroperoxides --> methyl acetate.

Furthermore, the BV-oxidation of methyl-ethyl ketone (butanone, MEK) generates ethyl acetate, which can be used for the aforementioned azeotropic distillation.

http://en.wikipedia.org/wiki/Baeyer-Villiger_oxidation

Of course someone without access to GAA may have a similarly difficult time obtaining concentrated H2O2, and this is not an easily prepared chemical.

Vesp · « **Reply #43 on:** November 28, 2010, 06:37:55 AM »

I think a bacterial method is worth mentioning, accordingly they can turn a water alcohol mix into 20% acetic acid.
yeast and sugar are happy to make the ethanol - and in fact work symbiotically since the yeast likes acidity. It makes it hard for anything else to thrive besides the acetobacter and the yeast.

20% if easily achieved, is a cheap method to acetic acid - especially when it only uses sucrose - which is how many cents per pound?

Sedit · « **Reply #44 on:** November 28, 2010, 07:15:05 AM »

That main expense is what it will cost to extract it to glacial status and to be honest im not sure at all.

The S2Cl2 seems to have promise but aquiring the S2Cl2 seems about as fun as getting Glacial acetic acid so its hard to say,

Iv been dying to make either Ketene or a vapor phase reaction possible but to be quite honest im a pussy. I really don't like death from poisons and explosions aren't really my thing either so until I ~~drink~~ gather up the courage to put it into action one day its going to be mental masterbation.

solidstone · « **Reply #45 on:** November 29, 2010, 09:21:16 PM »

Why not just add baking soda to vinegar until gas formation ceases. Evaporate... obtain Na-acetate. React with concentrated HCL and then distill the GAA off.

Or use the pyrosulfate trick noted in the propanoic acid thread to obtain the anhydrous acetic acid from the ester salt.

Sedit · « **Reply #46 on:** November 30, 2010, 02:51:19 AM »

Because the most concentrated you can get HCl is 36% meaning you are not going to get close to Glacial status using hydrochloric acid. Once Solvent extraction is perfected it may inturn proceed into using HCl on NaAc to produce cheep GAA but until then its not worth it. I also notice using stoich amounts of HCl and NaAc there are large amounts of HCl still present meaning there is an equilibrium setup that will do us in in the long run.

BTW have you ever proceeded to make 500 grams of NaAc from 5%vinegar and Sodium Bicarbonate. I use a large deep frier as the heat source for evaporations and it has given times unheared of for evaporating the gallons of solution yet it still is a huge pain in the ass. HUGE. And the acid it creates is contaminated with so much other shit unless the NaAc is crashed with acetone at the last minute that the GAA will never crystalize even when showing complete lack of water.

atara · « **Reply #47 on:** December 07, 2010, 01:12:15 AM »

A slightly easier method may be the reaction/distillation of calcium acetate with oxalic acid. Oxalic acid is a much stronger acid than acetic acid and so will displace it; furthermore the calcium oxalate is insoluble in almost every solvent and is hygoroscopic enough that the produced acetic acid will be very dry.

Calcium acetate shouldn't be too hard to prepare, and oxalic acid is of course OTC as a rust remover.

What baffles me more is the ubiquitous use of "anhydrous ammonium acetate". I cannot think of a simple way to prepare this chemical, as the combination of ammonium acetate with a dehydrating agent or the heating thereof always results in acetamide. Could ammonium carbonate (baker's ammonia) be substituted for ammonium acetate in reactions carried out in GAA? It would of course form ammonium bicarbonate and ammonium acetate in situ.

Wizard X · « **Reply #48 on:** December 07, 2010, 01:41:53 AM »

Quote from: atara on December 07, 2010, 01:12:15 AM

A slightly easier method may be the reaction/distillation of calcium acetate with oxalic acid. Oxalic acid is a much stronger acid than acetic acid and so will displace it; furthermore the calcium oxalate is insoluble in almost every solvent and is hygoroscopic enough that the produced acetic acid will be very dry.

Calcium acetate shouldn't be too hard to prepare, and oxalic acid is of course OTC as a rust remover.

What baffles me more is the ubiquitous use of "anhydrous ammonium acetate". I cannot think of a simple way to prepare this chemical, as the combination of ammonium acetate with a dehydrating agent or the heating thereof always results in acetamide. Could ammonium carbonate (baker's ammonia) be substituted for ammonium acetate in reactions carried out in GAA? It would of course form ammonium bicarbonate and ammonium acetate in situ.

You can use this method to make Oxalic Acid (Anhydrous) http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV1P0421 by the use of an organic compound like carbon tetrachloride to distil off the water.

Sedit · « **Reply #49 on:** December 07, 2010, 06:35:51 AM »

Well since ya'll brought it up. I now have about 50ml of pure Glacial acetic acid. And I don't just mean clean acid I mean I a big ass chunk of crystals of acetic acid with more to come but I understand the first pull cant get it all.

After some streamlining im positive this will become the norm for making GAA for the home scientist without a doubt.

solidstone · « **Reply #50 on:** December 07, 2010, 06:13:35 PM »

why not just add some HCL to sodium hypochlorite and gas the sodium acetate. Pack the carrier tube with CaCl2 or some similar desiccant.

I've had good success with drilling rubber stoppers to the correct diameter for air tight tube threading. Just 3 consecutive linked chambers... The bleach with HCL drop funnel, the sodium acetate vessel and then a last vessel containing concentrated NaOH solution to get rid of any nasty gasses.

Sedit · « **Reply #51 on:** December 08, 2010, 04:45:14 AM »

Im, confused.... Are you suggesting I gas NaAc with Cl₂? Why...

solidstone · « **Reply #52 on:** December 08, 2010, 04:53:58 AM »

Well the idea would be to gas your NaAc with chlorine in a saturated(or super saturated) aqueous solution. Does that make any more sense to you? The assumption is we would make HCL in situ which would react with the NaAc to form GAA and table salt.

Sedit · « **Reply #53 on:** December 08, 2010, 10:02:41 PM »

Cl₂ + H₂O <->HCl+HOCl. Given that hypochloric acid that forms is a strong oxidiser I wouldn't want to attempt this. So far from a monetary stand point Sodium Bisulfate seems like its going to be the cheepest means there is and the reactants can be mixed in a bucket. DCM or suitable solvent can be added then it can be filtered with a vaccume or pressure to yeild GAA.

This does not have the bad side effects that distillations need nor will it have the contaminates they normally have. It also allows one to add MgSO4 to dry the AcOH before distilling it to yeild GAA on the first run. I have about 100ml from my test now that freezes in the refridgerator and I haven't even distilled it yet I only distilled off the DCM and the Acetic acid froze over.

solidstone · « **Reply #54 on:** December 08, 2010, 10:53:59 PM »

Thankyou for correcting my quakery. What would happen if one tried to oxidize acetic acid? Would it happen? Would you have carbon dioxide come off and form formic acid? It sure would be nice to have a quick and simple means to make formic acid...

atara · « **Reply #55 on:** December 30, 2010, 08:11:32 AM »

Acetic acid probably cannot be converted to formic acid. Glycolic acid can, by oxidation / decarboxylation.

redcat · « **Reply #56 on:** March 17, 2011, 05:31:24 PM »

Quote from: Sedit on December 08, 2010, 10:02:41 PM

Cl₂ + H₂O <->HCl+HOCl. Given that hypochloric acid that forms is a strong oxidiser I wouldn't want to attempt this. So far from a monetary stand point Sodium Bisulfate seems like its going to be the cheepest means there is and the reactants can be mixed in a bucket. DCM or suitable solvent can be added then it can be filtered with a vaccume or pressure to yeild GAA.

This does not have the bad side effects that distillations need nor will it have the contaminates they normally have. It also allows one to add MgSO4 to dry the AcOH before distilling it to yeild GAA on the first run. I have about 100ml from my test now that freezes in the refridgerator and I haven't even distilled it yet I only distilled off the DCM and the Acetic acid froze over.

there are so many methods being discussed that I'm a bit confused about this post.
are you saying that you mix the bisulfate and acetate in a saturated MgSO4 solution, extract with DCM and distill it off?

Sedit · « **Reply #57 on:** March 21, 2011, 05:53:42 PM »

The basics are this Redcat...

Mix Bisulfate(H2SO4 would work as well)with Acetate to yeild Acetic acid. This is pretty dry Acetic acid from the start and on standing the formed Sodium Sulfate is a powerful dehydrating agent forming the decahydrate but only at lower temperature(room temp should be fine)

This ensure you already have a saturated "salt" solution so after allowing the dry powders to react for sometime you will see they liquify. Gental warming speeds this up but tends to stink up the place. I would give it about 24 hours to age to ensure you get the most reaction as possible.

Go over board with DCM or suitable solvent that evaporates quickly and cleanly.

Its a bulky mix so best to ring out using a cheese cloth or the likes and repeat with another DCM extraction. Distill your DCM at a low temperature and when you stop distilling you will be left with a slightlu yellow colored liquid which is GAA. It will crystalize on cooling but for some reason this is not always the case. If that happens stick it in the freezer and it will crystalize and the yellow contaminate can be poured off.

There appearence will be large flat plate crystals and after the first freeze it will be almost crystal clean and will freeze at room temperature.

It sounds complicated but its really all bucket chemistry so no worrys.

PS: The MgSO4 was used on the DCM prior to the distilling to ensure any entrained water is gone and the DCM/GAA mixture is bone dry.

redcat · « **Reply #58 on:** March 22, 2011, 03:13:22 AM »

thanks for clearing that up, it sounds easy enough

Sedit · « **Reply #59 on:** March 22, 2011, 03:37:43 AM »

It is easy, Perhaps time consuming and a bit messy but easy. It avoids the distillation which corrupts the product all to often.

I already started taking pictures and Im working with 822.6 grams of Sodium Acetate hydrate. When complete I will publish.

Author Topic: Glacial acetic acid from aq solutions (Read 779 times)

Sedit

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atara

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Vesp

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solidstone

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Wizard X

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redcat

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