80% Acetic Acid

[DiMethyl]

I got a good buy on some 80% acetic acid.
Since most of the literature that I review refers to
glacial (anhydrous) acetic acid, I was wondering if anyone
knows of a good way to convert the 80% to the glacial?
Drying salts might be inappropriate due to the high
concentration of H2O in the 80%
Perhaps distiallation.

[spectralmagic]

SWISM distills (acetic acid boils at 117.9), then dries over a dessicant (usually MgSO4) to get rid of the residual H2O.  In a pinch SWISM has been known to start with household vinegar (~5%)!
To Bee, or not to Bee...  ;-)

[Fully_Auto]

Swfa has attempted to distill vinegar and it didn't work well. Swfa was left with a flask filled with disgusting dark brown crap and salt in his flask in the end. Swfa will never consume that brand of vinegar again. Just distill your gaa with a column.
The Ultimate Weapon Can't be controlled, banned or confiscated. Your weapon's your mind.

[DiMethyl]

I don't see where acetic acid has any azetopes with
water.
The bp of the AA is 118 and for water its 100 so some
degree of fractionizing would perhaps be appropriate.
I don't see why it would not work.

[Chromic]

You need quite a few stages to separate GAA from water.

[Elementary]

In reply to :

Swfa has attempted to distill vinegar and it didn't work well. Swfa was left with a flask filled with disgusting dark brown crap and salt in his flask in the end. Swfa will never consume that brand of vinegar again. Just distill your gaa with a column.

Try using distilled clear vinegar rather than brown malt vinegar !

Extract :

Pure acetic acid is best obtained by forming crystals of cupric acetate (by adding excess of copper carbonate, filtering, and crystallizing), and then, after heating them gently to drive off their water of crystallization, distilling these crystals with concentrated sulphuric acid.

(Copper Carbonate can be obtained via potter suppliers !)
Umm, how interesting !!

[Fully_Auto]

In reply to :
Try using distilled clear vinegar rather than brown malt vinegar !

It said distilled vinegar right on the bottle! I swear. It was incredible. The product is sold by a large supermarket. It says the name of that supermarket right on the bottle. "Distilled white vinegar." I wont eat that shit ever again. The only reason SWFA tried this was because he was in a jam at 3:00am. Always buy GAA makes life easier.

The Ultimate Weapon Can't be controlled, banned or confiscated. Your weapon's your mind.

[terbium]

Pure acetic acid is best obtained by forming crystals of cupric acetate (by adding excess of copper carbonate, filtering, and crystallizing), and then, after heating them gently to drive off their water of crystallization, distilling these crystals with concentrated sulphuric acid.
Or use sodium bicarbonate (baking soda) instead of copper carbonate.

[Elementary]

The supermarket distilled vinegar must of had sugar added to it then. When I used it (well known UK brand) I had no problems, anyway I'm a photographer now   , so I don't need vinegar anymore !
Umm, how interesting !!

[Chromic]

When I distilled clear and colorless vinegar (to react with baking soda to make sodium acetate) there was a film of black crap that liked to stick to the inside of the flask as well. Go get pure GAA. Who the heck sells just 80% acetic acid? I've seen stuff around 5%, 10%, 30% and 100%. Never an 80%.

Ask for 100% acetic acid, I'm sure they'd stock it.

btw, what synthesis are you talking about?

[Elementary]

The UK photographic company I use sells 80% acetic acid but not 100%.

It is used in the stopbath !

Beware, some acetic acid that is available for stopbaths also contains pH indicators.

A lot of people are using citric acid now for stopbaths as it odourless.
Umm, how interesting !!

[Chromic]

I've been interested in this subject for the OTC production of GAA ever since writing the peracetic document. I've placed with this system a number of times now and I have to say that GAA cannot be distilled from any low percentage acetic acid mixture.

I used 200ml of ~60-80% acetic acid. I got less than 15ml of GAA (ie the portion boiling above 115C).

I ran the distillation at a very slow rate of 1 drop every 2 seconds, and from 200ml of ~80% acetic acid and with a 500mm glass fractionating column. The separation of water from acetic acid is nearly impossible by distillation.

[Semtexium]

could one add H2S04 and distill...?  I think Lugh mentioned it in another thread...
            Mean People Suck             

[lugh]

Post 382030

(lugh: "Commercial Process", Chemistry Discourse)

[Semtexium]

Thats the one!!!  
            Mean People Suck             

[Protium]

The only concentrated acetic acid stop baths at the photoshops in my area are "indicating stop baths".  As a matter of fact the lady at the photoshop did not know what I was talking about when I asked her for a "non-indicating stop bath".  On the front of the bottles is "Indicating stop bath", and the only information on the label is the concentration, and "Contains Acetic acid" followed by the CAS#.

Does anyone know what the pH indicator is?
Pr(+)tium

[TheBlindGenius]

does not contain indicator.  They have 28% and "100%" as the (obviously non-chemist) small photo shop owner put it.  It cost me $20 a gallon for my "100%" acetic acid.  I use it for photography of course.  Go to more photo supply places.  You will eventually find one that carries it or will get it.