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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Chinnup on June 01, 2009, 11:45:35 PM

Title: remove DMSO
Post by: Chinnup on June 01, 2009, 11:45:35 PM

hello
My product dissolve in DMSO(1~2ml). It's kind of complex that may decompose at high temperature, and it can dissolve in water. Hence, vacuum pump at high temperature and extraction by organic solvent are not working. What can I do to remove DMSO?

if you have any crazy idea
i'll really appreciate

Title: Re: remove DMSO
Post by: Arctic-Nation on June 02, 2009, 04:43:55 AM

DMSO is a b$*%( to get rid of occasionally. If your product is thermally unstable, you can just try to dry it under high vacuum at room temperature or slightly above. Another possibility might be to stream air over or through it (use the pressurized air system and a fine pipette).

The best solution however is lyophilization, but as you posted here you probably don't have the necessary equipment. That's not to say that you can't just try it with a normal vacuum pump, of course.

Title: Re: remove DMSO
Post by: Chinnup on June 04, 2009, 06:23:51 AM

Thanks for your idea, but..
I don't know the "high' vacuum you mean. I have tried -750mmHg at 308k, but it's not working. what is more, lost of people said that lyophilization can dry DMSO. What is the exactly value about the vacuum degree?(ex: mmHg)
Another guestion is "stream air over or through it" that you talk about. I don't understand what you mean, but I'm really intreseted about it.

thank you again

Title: Re: remove DMSO
Post by: dfreema7 on July 21, 2009, 09:56:06 PM

You can mix a little bit of ethanol in with the DMSO to lower the boiling point. Anywhere from 10:1 to 1:10, really, and then you could try drying off the solvent under a vacuum pump. Our lyophilizer can remove DMSO/ethanol (10:1) after it has been frozen (about -48C) and vacuum applied at about 0.05mbar, which is about 0.04 Torr.

Title: Re: remove DMSO
Post by: arborescent on August 02, 2009, 03:29:14 PM

high vacumm means very low pressure; generally you need a diffusion pump to achieve that vacuum.
But I think with a standard pump while heating moderately, you should be able to get rid of your dmso.

Title: Re: remove DMSO
Post by: macman104 on August 02, 2009, 04:00:34 PM

You can use the nomograph here to figure what pressure you need to achieve to heat it to a low enough temperature.  We can achieve 0.4mmHg with our vacuum pump, so DMSO actually boils off at room temp.  Is it possible to recrystallize your sample from the solution?

http://www.sigmaaldrich.com/sigma-aldrich/areas-of-interest/chemistry/solvents/learning-center/nomo-assets.html