Home > Community > How do you remove DMF without using a vacuum pump ?
Upvote

23

Downvote
+ Solvents
+ Hydrophobicity
+ Dimethylformamide
+ Organic chemistry
+ Solvent extraction
Posted by
Ooi Teng He

How do you remove DMF without using a vacuum pump ?

Damien Leimbach  Follow

solvent exchange

More

Upvote

VOTE

Downvote
Bette Stalford  Follow

In my experience, DMF is slightly more soluble in DCM than in EtOAc so I always extract with EtOAc (if the mixture is soluble).  I run an extraction by first diluting with excess EtOAc, then wash with sat. aq. brine (2X) followed by washing with H2O (2X).  Do not vigorously shake the sep. funnel, but slowly invert it a coupling of times to mix or an emulsion can form.  If the reaction was run with a base (e.g. DIPEA or Et3N), I add a single sat. aq. NaHCO3 wash after the brine wash and before the water wash.  Another point to be made here is to never back-extract your aqueous layer with more EtOAc, it will pull more DMF into your organic layer. Hope this helps and good luck!

More

Upvote

VOTE

Downvote
Liz O'Callaghan  Follow

Use toluene as extraction solvent.  Wash toluene phase with water or brine once after extraction.  Toluene can take a little work to pump off, but it is much easier than DMF.
See link for the article that led me to this method.
http://pubs.acs.org/doi/abs/10.1021/op060154k

More

Upvote

VOTE

Downvote
Ask Jadzie  Follow

In my experience, DMF is slightly more soluble in DCM than in EtOAc so I always extract with EtOAc (if the mixture is soluble).  I run an extraction by first diluting with excess EtOAc, then wash with sat. aq. brine (2X) followed by washing with H2O (2X).  Do not vigorously shake the sep. funnel, but slowly invert it a coupling of times to mix or an emulsion can form.  If the reaction was run with a base (e.g. DIPEA or Et3N), I add a single sat. aq. NaHCO3 wash after the brine wash and before the water wash.  Another point to be made here is to never back-extract your aqueous layer with more EtOAc, it will pull more DMF into your organic layer. Hope this helps and good luck!

More

Upvote

VOTE

Downvote
BeachLover62  Follow

DMF is soluble in water, you can extract with ether,DMF slighty soluble in ethyl acetate.
Batter use ether as a solvent for workup purpose.

More

Upvote

VOTE

Downvote
Declining USA  Follow


Removal of DMF from reaction mixtures may depends on the reactions and the nature of the products. I could suggest some following things.
1. Try to use less volume of DMF starting the reaction. Don't worry about the solubility of the reactants as it will be solubilized during the course of reaction.
2. DMF is more soluble in DCM , compared to ETOAc. Better try to extract in ETOAc or ether.
3. DMF is soluble in cold or chilled water. Firstly, treat the reaction mixtures with with organic solvent then add cold water and during extraction, let the two layers get separated completely with ample amount of time. Wash the organic layers with brine twice at the end.
4. If products are thermally stable enough, then rotary or high vacuum pump can be used with temperature range 50-60°C but long period of time is not recommended and must attach a solvent trap during evaporation.

More

Upvote

VOTE

Downvote
David Lovering  Follow

I did many reactions in DMF and this is how I always perfectly got rid of it from my products without distilling: repeated extractions diethyl ether/water. DMF does not mix with Et2O very well so if your product is soluble in this solvent, you can dissolve it and then extract 4-5 times with water. Be careful not to use too much Et2O, otherwise you end up with some DMF in it. Good luck!

More

Upvote

VOTE

Downvote
Andrew Wrigley  Follow

Rxn mix. added in cold crushed ice, stirrer well 10-15 minit. may be more  or repeat one time more

More

Upvote

VOTE

Downvote
Connie Francisco's Space  Follow

It is very easy to remove by using ice cold water and wash with brine solution (3 X) and then again wash with cold water.

More

Upvote

VOTE

Downvote
Chas Alston  Follow

Extraction and washing with H2O is a very good method, but sometimes does not solve the problem. Especially when the product is polar, then it's hard to extract it from the water/DMF layer.
For solid products precipitation often may be the easiest way to get rid of DMF (and other polar high boiling solvents).
If the product is solid and not soluble in water, DMF can be easily removed by the addition of excess amount of water (precipitate should form, cooling may fasten the process), filtration and washing the obtained solid with water.
If the product is soluble in water but not soluble in Et2O, then dilute with excess Et2O, cool down, filter out the solid and wash with cold Et2O. This works well especially for inorganic and organic salts (generally very polar compounds).

More

Upvote

VOTE

Downvote
Anne Eastman  Follow

DMF is completely soluble in water u can remove by solubilizing in it and after extract it by ethyl acetate. repeat it several times.

More

Upvote

VOTE

Downvote
Ali McGuire  Follow

Just add water to the reaction mixture (DMF) and then extract compound from DCM.

More

Upvote

VOTE

Downvote