Sciencemadness Discussion Board

Making Sodium Acetate, need a fast way to purify Acetic Acid.

The Fountain of Discordia - 19-5-2009 at 03:56

I'm making a batch of Sodium Acetate, but wanted to work with a higher grade of Acetic Acid. I looked up the melting point of Acetic Acid, which is 16.2*C. My basic procedure would be to:

1. Lower temperature of vinegar to below 16.2*C
2. Let solidified acid acumulate at bottom/top of container, depending on density.
3. ???
4. PROFIT

Of course this will not work as I have found out the sodium acetate is soluble in water(WolframAlpha). Are there any easy to obtain chemicals I could use to lower solubility?

ScienceSquirrel - 19-5-2009 at 04:06

Sodium acetate is readily available as it has a lot of uses.
Making it from vinegar is bordering on the masochistic as you will only get tens of grams from a litre of 4 - 6% vinegar.


The Fountain of Discordia - 19-5-2009 at 04:15

Sure, and I've already ordered .5 kg of it, but I still want to produce it myself as an excersise.

ScienceSquirrel - 19-5-2009 at 04:26

Take a litre of distilled vinegar and add a strong base eg sodium carbonate in small portions with stirring until it is faintly basic eg pH 8 to indicator paper.
Pour the solution into a pan and concentrate to ca 20 - 40 ml, you may be better off using a water bath instead of direct heat in the later stages.
Place in the coldest part of the fridge or use an ice bath and allow to crystallise.

Hydragyrum - 19-5-2009 at 04:52

I made some just the other day - from vinegar. I bought the cheapest brand I could find, which was completely colourless (so I am hoping there's nothing besides acetic acid in the water).

I then assumed a concentration of 5% and added the predicted amount of NaHCO3. After reaction subsided, I noticed no further smell of vinegar, and heated the solution (carefully) to expel the rest of the dissolved CO2.

After this was done, I reduced the volume to about 1/5 of original (by heating), and found that crude product separated overnight.

Sedit - 19-5-2009 at 09:06

There will be other organics in there no matter if its distilled white vinegar or not. The means you took to crystalize the product should clear more of that out of your sodium acetate. A wash of the precipitate with acetone should make sure that the majority of the contamination is washed off the outside of the crystals.

~Sedit

Hydragyrum - 20-5-2009 at 03:01

My solvent resources are meagre and I don't have acetone. Despite this, I guess a recrystallisation would be sufficient to clean it up. I wanted it for making copper acetate, and similar, and figured crystallised NaOAc would be better (and more quantitative) than vinegar ;)

4-Aminophenol - 20-5-2009 at 12:11

Hi

In germany you can buy "vinegar essence" thats 25% acetic acid, but I´m not sure if that´s selled in your country, too.

If not you could buy 10l 5% vinegar and add Soda until the ph-value is 7. Evaporate the water. Now you´ve got about 680g sodiumacetate. Add concentrated sulfuric Acid and distill the acetic acid.

User - 20-5-2009 at 14:56

Iam not sure if it is sold in your country.
But in the stores we in holland call toko's (malaysian for store) they sell all kinds of eastern products.
They sell vineger with a strenght of 80%, its meant to be dilluted.

Hydragyrum - 21-5-2009 at 01:01

Wow, 80%? We do have asian shops here in Australia so maybe I can find this product here too - I'll ask around.

Rich_Insane - 2-6-2009 at 21:11

Isn't that like corrosive (80% acetic acid)?

I know there is a good simple extraction out there, but if you are short on the materials, Mix in NaCO3 or NaHCO3, until pH 7. It is better in my point to have more acetic acid than the crystalline base. Keep adding the base until pH 7 on an indicator or a meter. Boil the result down, or distill it to remove the acetic acid. You could do further recrystallization to get rid of excess base. The white vinegar here in Oregon is 18%.

The Fountain of Discordia - 3-6-2009 at 14:39

Quote: Originally posted by User  
Iam not sure if it is sold in your country.
But in the stores we in holland call toko's (malaysian for store) they sell all kinds of eastern products.
They sell vineger with a strenght of 80%, its meant to be dilluted.


I live in japan. I'm sure there are all manner of interesting things here, but I cannot read kanji, just the kana. 'tis mighty annoying.

Sedit - 3-6-2009 at 14:46

http://www.geocities.com/scripturalphysics/etc/CopperAspirin...

If you want to go thru this to synthesis Copper acetate then you may as well form it under dilute conditions so when you evaporate the bulk of the water you will be left with copper acetate instead of sodium acetate. Just scroll down on the page for a copper acetate synthesis.