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Author: Subject: Purification with Sodium Bisulfite?
lancer3000
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[*] posted on 30-9-2011 at 23:27
Purification with Sodium Bisulfite?


Good Evening guys.

I need a bit of re-assurance on this process at hand please.

I have heard of the use of sodium bisulfite for use of purification of amine, by removing un-reacted amide, and other unknowns. Please advise.

A little run down:
It involves adding sodium bisulfite to solution until Ph reaches around 11. A layer separates, upper aqueous, lower a oil/freebase.

The upper aqueous layer is decanted, and dripped slowly onto a naoh/h20 solution heated to 70c, stirred, and cooled. Extract with solvent, and decant solvent. This is then dried, filtered, and gassed.

The oil layer must contain more impurities I imagine? This is heated with solvent until almost boiling, then settles, and solvent decanted off. Repeated 3 times. Chilled in freezer, and filtered. THIS is where the amide will remain in the filter.

This oil is then washed 3 times with a 5% naoh solution, and naoh solution discarded. Solvent is extracted with hcl until ph 7, and decanted, than repeated with hcl until ph 2-3. extracts combined. washed 3 times with solvent. This is then mixed with naoh + nacl + h2o. solution is extracted with xylene (gently), dried and gassed.

**seems like a lot of steps, but this probably leaves a nice product. Does this all sound proper, or can any of it be simplifed?

Thanks, and have a great weekend.
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Nicodem
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[*] posted on 1-10-2011 at 01:33


Doesn't make any sense to me.

PS: Open unanswerable and/or referenceless threads only in the Beginnings section where I'm moving this.
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Nicodem
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1-10-2011 at 01:33
lancer3000
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[*] posted on 1-10-2011 at 12:10


doesnt adding bisulfite, attach itself to other things, allowing it to be filtered/separated from the unwanted, then removed with an acid? I think this is where it is going, probably gives nicodem a better idea...
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