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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: biggestdav on April 14, 2010, 04:08:54 PM

Title: Dealing with emulsions during aqueous extraction
Post by: biggestdav on April 14, 2010, 04:08:54 PM

Hi,

I have had reactions in the past where work-up has been difficult due to formation of emulsions. This is particularly apparent when acids such as TFA have been neutralised with NaOH then extracted with DCM or ether. Does anyone have a sugestion on how to combat this problem other than saturating the aqueous layer with brine salt?

Many thanks

Dave

Title: Re: Dealing with emulsions during aqueous extraction
Post by: azmanam on April 14, 2010, 04:20:20 PM

poke at the phase boundary and scratch the sides of the sep funnel with a spatula sometimes works somewhat.
add a lot of water sometimes works somewhat
adding brine, as you mentioned, sometimes works somewhat
filtering through celite usually works in a last-case scenario.

Title: Re: Dealing with emulsions during aqueous extraction
Post by: Shomei on April 14, 2010, 11:07:55 PM

Sometime, saturating the water phase with NaCl helps. (In my experience)

Title: Re: Dealing with emulsions during aqueous extraction
Post by: Shomei on April 15, 2010, 06:06:12 AM

Sorry, I did not know that brine = NaCl sat. water.

Title: Re: Dealing with emulsions during aqueous extraction
Post by: AC Prabakar on April 17, 2010, 03:38:28 AM

Filtration of the emulsion over hyfolw bed(or as early told on celite) may be helpful.But you should check the product content after filtration.