My reaction mixture has DMF and water in ratio 1:10 (DMF:Water). After the completion of reaction, I need to extract my compound which is highly polar. When, I use Dichloromethane or Ethyl Acetate, DMF extracts out. After rigorous washing with water some traces of DMF still persists.
Please let me know any other easy method to completely get rid of DMF.
Remains of DMF from the extract can be removed with activated carbon, especially if you repeat the operation 3 times with a fresh AС and each time to stand for at least half an hour.
http://chem.rochester.edu/~nvd/pages/solvents.php?page=solvent_workup
Dear Dr. Mauricio,
I am thankful to you for your interesting way. I will try to do it. But I am afraid of spilling of my compound. I hope it works.
If you add some toluene to your mixture, and then use the rotary evaporator, the DMF co-distills with the toluene and it can be removed. I've tried this and it works pretty well.
Dear Oscar,
Many thanks for the answer. It is indeed an easy way. I will try it.
i think acidify your reaction mixture with hydrochloric acid . after that extract your comound with methylene chloride
I think above suggestion work well.
My suggestion is that if your compound is solid then after distillation of solvent when only DMF remains in traces added antisolvent like IPE or MTBE to precipitate your product and filtered and washed with antisolvent DMF completely removes.
I will suggest you wash your ethyl acetate fractions with Sat. LiCl. That works with me always.
For 5 mL of DMF or DMSO, I use 5 X 10 mL of water during the aqueous wash. This should remove all of the DMF or DMSO. And then 5% LiCl (aq) to remove traces of DMF, then 0.5 N HCl. I hope this work for you.
Ii some case I just wash my product with traces of DMF with diethyl ether. And after extraction I always wash organic layer with saturated solution of NaCl.
washing organic layer (Ethyl acetate) with Sat.NaHCO3 also works well
Thank You so much Dr. Claire, Mohammad, Prof. Simon, Kyriukha and Vasu. This is really helpful.
I remove DMF, (which I use often) by co-evaporation with water or EtOH, on rotary evaporator (water pump, app. 20 mmHg) on 70-80 degrees C. Then, remove traces with vacuum pump (app. 1 mm Hg). All of this I usually do, after reaction complete, and before workout.
You should dry your final fraction under pressure through an aspiration device.
Sachin,
For me, washing ethylacetate or DCM or diethyl ether layer with brine (5-6 washes) got rid of DMF well enough. Another way to that worked well is washing with 5-10 % LiCl (aq).
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