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Topic: DMF removal by extraction  (Read 25300 times)

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Offline ID101

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DMF removal by extraction
« on: December 01, 2009, 03:21:12 PM »
Hi,

I'm running a coupling reaction between Hematin and PEG in DMF, and am looking to remove the DMF solvent by extraction with EtOAc.  Is this possible?  If I add 10X's as much water to the DMF and then extract with EtOAc, will the DMF enter the EtOAc phase and separate from the aqueous phase (leaving the coupled product in the aqueous phase)?  Any information on this would be great.

Thanks very much. 

Offline stewie griffin

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Re: DMF removal by extraction
« Reply #1 on: December 01, 2009, 03:40:57 PM »
The DMF will mix with the EtOAc. However, it won't mix much with diethyl ether. Whenever I run one of my reactions in DMF, I extract 5 times with a decent amount of diethyl ether (but not crazy amounts). I've never had a problem doing it this way... yields have always been fine.
Hope it works for you.

Offline irciniastatin J

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Re: DMF removal by extraction
« Reply #2 on: December 01, 2009, 09:27:06 PM »
Ditto, Et2O is the way to go.2

Offline Momer

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Re: DMF removal by extraction
« Reply #3 on: December 01, 2009, 11:30:19 PM »
I have similar problem, I have DMF mixed with TriEthylAmine and a new amoxicilline derivative, and I want a way to extract the pure (I call that derivative Nimoxicillin) Nimoxicillin from that mixture without destroying Nimoxicillin, I were trying to separate them by column ,but triethylamine try to have a spreading appearance on TLC (big tailing ). And I have a limited choices in my college to do such a research, I use the available technique in the lab. I don't have HPLC or GLC or other high developed technique, just Column (Silica Gel) and TLC , I were trying to solve this problem but the results are bad.

I hope some guidance from you.

By the way I'm undergraduate Pharmacist student, I'm fond of chemistry research.

Your kind assistance will be highly appreciated.

Thanks.

Momer


Offline stewie griffin

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Re: DMF removal by extraction
« Reply #4 on: December 02, 2009, 08:07:57 AM »
Well I don't know how acid sensitive your derivative is, but try to acidify the aq. layer (with say 10% H2SO4 and extract with Et2O. The triethylamine should get protonated and therefore become an ammonium ion which will stay in the aq. layer rather than go into your organic layer during the extraction. Then the problem is solved.
If your derivative is acid sensitive, then instead of acidic water/Et2O extraction, do an extraction with diethyl ether and saturated copper sulfate (a cool blue solution!). The copper will coordinate to the amine and help pull it into the organic layer.

Offline movies

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Re: DMF removal by extraction
« Reply #5 on: December 08, 2009, 11:46:53 AM »
The best way I have found to remove triethylamine is to wash with aqueous sodium citrate or aqueous citric acid.  Works like a champ.

Offline Momer

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Re: DMF removal by extraction
« Reply #6 on: December 27, 2009, 10:34:27 PM »
Well I don't know how acid sensitive your derivative is, but try to acidify the aq. layer (with say 10% H2SO4 and extract with Et2O. The triethylamine should get protonated and therefore become an ammonium ion which will stay in the aq. layer rather than go into your organic layer during the extraction. Then the problem is solved.
If your derivative is acid sensitive, then instead of acidic water/Et2O extraction, do an extraction with diethyl ether and saturated copper sulfate (a cool blue solution!). The copper will coordinate to the amine and help pull it into the organic layer.

I had tried that but the result was negative, there is no any Triethylamine in the organic layer by using TLC, do have any suggestions? Anyway thank u a lot....

Offline stewie griffin

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Re: DMF removal by extraction
« Reply #7 on: December 29, 2009, 02:16:37 PM »
Momer: I'm confused.. I thought the point was that you didn't want the triethylamine in the organic layer. So why is it a problem that you  don't see any triethylamine in the organic layer now?
BTW, I'm not sure you can really track triethylamine by TLC. I guess it depends what stain you use... but I don't think I've ever seen triethylamine on my TLC plates.
Even if there is some triethylamine in the organic layer, can you not vacuum it down and then put the stuff on a high vacuum pump for an extended period of time??? That should take off the triethylamine.

Offline Momer

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Re: DMF removal by extraction
« Reply #8 on: December 31, 2009, 05:16:45 AM »
I've confused too....

I need to get rid of the TEA from my mixture which is (TEA + DMF + derivative of amoxicillin ).

TEA has splash spot on TLC as u can see in this image ( the far right spot)


I want to get the derivative of amoxicillin pure by using a column. Since TEA has this splashy properties I think it could give rises to problems during the separation, so I decided to isolate this compound first by other technique before using the column.

Thank for your suggestion that is using the vacuum, I will study it with my professor.

I will be happy If you have any further suggestions.


Offline bromidewind

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Re: DMF removal by extraction
« Reply #9 on: December 31, 2009, 11:01:12 AM »
I found two lab techniques to remove DMF and TEA from your solutions. The second link is a paper that I found about removing TEA from synthetic wastewater that may or may not be helpful to you. I didn't read the entire paper, just the abstract.

http://chem.rochester.edu/~nvd/workupnotes.html
http://www.cababstractsplus.org/abstracts/Abstract.aspx?AcNo=20073289557

My professor has mentioned using chromatographic screening as a means of separation. I am not sure of the exact technique behind this, but I would recommend perhaps exploring HPLC.

Offline cpncoop

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Re: DMF removal by extraction
« Reply #10 on: January 05, 2010, 04:15:59 PM »
Hi,

I've worked pretty extensively with both of these things at scale.  In order to remove DMF, dissolve your material in TBME and wash with a 50% brinde solution (2X).  Dry over Na2SO4 and evaporate.  Take the residue up in heptane and evaporate to remove the TEA (it boils lower than heptane). 

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