Sciencemadness Discussion Board

Separating borax from a mixture?

darkflame89 - 9-8-2004 at 01:24

I need a little help: does anyone have any idea how to separate borax from a mixture of powdered borax and powdered hand soap?

guy - 9-8-2004 at 12:38

From my searching, it seems that borax only dissolves 6grams/100grams of water.

So maybe dissolve all the soap and then collect the borax

chemoleo - 9-8-2004 at 15:36

If this doesnt work:
1. Dissolve all your borax/soap in water, make it as concentrated as possible.
2. Add HCl conc, and preciptate the fatty acids AND H3BO3.
3. Filter precipitate.
4. Shake up the precipitate with acetone. The fatty acids will dissolve, while H3BO3 won't. Do that 2-3 times to get completely rid of the fatty acids. Dont use ethanol, as it will react with the H3BO3 to a small extent - particularly if HCl is still present.

Then you can do whatever you want with the boric acid - i.e. backreact it with the appropriate amount of NaOH to get your borax back.
That should definitely work :)

darkflame89 - 10-8-2004 at 01:46

Must it be conc. HCl? I understand that acids are required to hydrolyse the soap to fatty acids, but i don't have such acids. The strongest concentration of HCl OTC is 9%. Could some other be used to convert all that soap to insoluble salts in water?

fvcked - 10-8-2004 at 01:57

"The strongest concentration of HCl OTC is 9%. "
Go to a pool supply house, they have 35% HCl. I have also found it by the paint supplies at a wal mart and a menards.

EDIT, didnt know you live in singapore, but for others in different countries the above stands.

[Edited on 11-8-2004 by fvcked]

darkflame89 - 11-8-2004 at 01:38

The country where i live in ain't have any pool supply house. because there's only public pool in Singapore, and common people don't buy such chemicals as there are no private pools or such. Such pool supplies must be obtained directly from the manufacturer. As such this is a big problem to me for i do not know where the manufacturer is.

[Edited on 11-8-2004 by darkflame89]

guy - 11-8-2004 at 20:37

You can always make your own HCl

unionised - 12-8-2004 at 08:24

Use dilute HCl, then evaporate off the water, leach the fatty acids out with acetone then wash the salt off with as little water as possible.