Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: peptideismylife on June 07, 2011, 07:22:05 PM
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Hey guys,
How can I remove DMSO? I put it in the roti but it doesnt remove it....
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Rotavap will not remove it, even at high bath temperatures.
You need to put on high vacuum (oil pump) and preferably heat it slightly if your compound can tolerate it.
As far as I know azeotropic distillation is not possible.
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Rotavap will not remove it, even at high bath temperatures.
You need to put on high vacuum (oil pump) and preferably heat it slightly if your compound can tolerate it.
As far as I know azeotropic distillation is not possible.
you also might be able to reduce the bulk of it by fractional recrystallization - DMSO has a pretty high MP.. question is if your compound forms a complex crystal with DMSO or separates out as DMSO cools, separates out, or if DMSO separates out and DMSO+compound remains a liquid above that.
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Is your compound soluble in any chlorinated solvents (DCM or choroform??). Try diluting the DMSO with water then extracting with DCM or chloroform.
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If your compound is quite low in polarity you can wash it out, as mentioned already.
I usually dissolve in EtOAc and wash with 1:1 brine/water a few times. This works very well for DMF - I haven't tried it for DMSO. Note that if you extract with an organic several times you will probably just back-extract all the DMSO, so I'd do aqueous washes as opposed to organic extractions. I'm basing this on my experience with DMF, so it may not transfer exactly.
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I've had good luck using the aqueous extraction method. The more water the better. Sometimes a little DMSO will carry over, but that can be fairly easily removed under high vac.
I've also set up a short path vacuum distillation apparatus to get rid of DMSO from solids.
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If your compound is less polar then you can try extraction with diethylether and it would be better to have chilled aq. medium. In my case it worked well.
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DMSO is a polar solvent dissolve in water so use the DMSO-H2O phase extracted with diethyl ether.
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It is not my own experience, but my colleague uses brine instead of just water.
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If your product is less polar then try with ethyl ether extraction process, If littlebit polar then better EtOAc. In my case I usually isolate with EtOAc extraction and then crystalization. But, if the product is oily or gummy and highly polar then probably high vacuum distilation is the only way.
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Are you using DMSO as solvent for reaction?
Your desired compound is soluble in organic solvent or water?
If you would like to remove by work-up/extraction try the following article's procedure.
Organic Process Research & Development 2007, 11, 160-164
This article will give u exact qty. of DMSO carried over in organic phase as shared by other members!!
Good Luck!
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Why do you keep on re-hashing the same stupid question?
This is the fourth or fifth or even sixth time you have asked this!
Can the moderators not do something here?
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Hey discodermolide,
take a look because I have only ask once. Look at the first message...it was from 7th June, the first time that I've asked. So, there are not fifth or even sixth time....please don't lie. It's not my fault if someone answer one month later and you think that is a new topic...
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Hey discodermolide,
take a look because I have only ask once. Look at the first message...it was from 7th June, the first time that I've asked. So, there are not fifth or even sixth time....please don't lie. It's not my fault if someone answer one month later and you think that is a new topic...
Not correct, this question has been asked and answered several times. Most post coming from you.
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So show me how many times I asked this question please...
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So show me how many times I asked this question please...
Check the search function. It does not help when one is registered under different names.
At the risk of being banned, I don't think you are cut out for this chemistry, perhaps try something else, a bit easier for your level?
You still did not have the manners to answer my reply to the polarity question!
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Discodermodile,
I am not going to discuss this stupid thing. In fact we are here to learn, not to discuss about stupid thing. As a said, I have asked only once. I don't have more names because I dont need to ask more than once.
Anyway, I dont understand why u are so agressive to me. To be honest it something that surprising me a lot.
However I wish u a nice evening and all the best....
Ciao
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Discodermodile,
I am not going to discuss this stupid thing. In fact we are here to learn, not to discuss about stupid thing. As a said, I have asked only once. I don't have more names because I dont need to ask more than once.
Anyway, I dont understand why u are so agressive to me. To be honest it something that surprising me a lot.
However I wish u a nice evening and all the best....
Ciao
Your manners and intelligence leave a lot to be desired. I am not being aggressive but honest. Your level of knowledge leaves a lot to be desired. You ask before doing the experiment. It should be the other way around.
In all my 30 years of research and development I have never come across this approach in synthetic organic chemistry.
Chemistry is an experimental science so do the experiments first.
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Thanks for your advices. And I am talking seriously...u are older than me and also with a huge experience in chemistry...so Im sure that your advices could help me.
Last topic that I write (take a look), is after the experiment....so more or less I am following your advices....
Thanks
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Thanks for your advices. And I am talking seriously...u are older than me and also with a huge experience in chemistry...so Im sure that your advices could help me.
Last topic that I write (take a look), is after the experiment....so more or less I am following your advices....
Thanks
I'm sure I could help you, but if you don't have the good manners to reply to an answer why should I try and help? How would you feel if you took the trouble to answer someone's question(s) and did not receive reply, positive or negative?
Instead of sitting at the PC get in the lab and do lots of experiments.
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You two behave yourselves.
Topic locked.