danaH Posted June 8, 2011 Posted June 8, 2011 Hey all,,, I have synthesised the compound 1,3-Diisopropylimidazolium chloride according to the patent procedure, and i have it by NMR, but it still contains contaminations, and i get it as a brown tar insted of brown solid,, what is the best method to wash this product? i washed few times with THF, but it still oily instead of solid! thank you,, Dana
hypervalent_iodine Posted June 8, 2011 Posted June 8, 2011 (edited) Sounds like you might have solvent in there and possibly water. Do you have many solvent peaks in your NMR? Easiest way to get rid of solvent is by freeze drying it off or by pumping it down under high vacuum. Otherwise, if the contaminants are less volatile than your product you could distill your product off, provided it isn't overly temperature sensitive. Edited June 8, 2011 by hypervalent_iodine
danaH Posted June 8, 2011 Author Posted June 8, 2011 i will send you the NMR tomorrow when i will be at the Faculty, i dried it under vacuum and high temperature, it doesn't solidify yet... have you tried this reaction before? thank you for the help! Dana
hypervalent_iodine Posted June 9, 2011 Posted June 9, 2011 No, I have not, but I have a lot of experience with things that won't solidify. How long did you leave it under high vac? Try doing it without the high temperatures and blast it with a heat gun at lowish temperatures every so often. Otherwise, you could try distilling it. What solvents have you used through out the reaction? EtOAc?
danaH Posted June 9, 2011 Author Posted June 9, 2011 The acetone is from the chloroform-D bottle we have,,,, someone contaminated it ! i will try to dry it more on the high vacuum..the problem is that it becomes like a tar and doesnt solidify the solvents i used are :THF, acetone, DCM, water, Toluene thank u Dana
hypervalent_iodine Posted June 9, 2011 Posted June 9, 2011 Your NMR peak at 1.56 is from water. That may be your problem, although it could have just as easily been from your NMR tube/chloroform. If it is a contaminant, you may like to try using a drying agent of some description. How hygroscopic is your compound? (Also, this: http://chem.chem.rochester.edu/~nvd/NMRSolventImpurities.pdf may help you in future. It's a great paper for working out solvent impurities).
danaH Posted June 9, 2011 Author Posted June 9, 2011 it is very hygroscopic,,,,thank you very much! this forum is great
mississippichem Posted June 9, 2011 Posted June 9, 2011 Tell your underlings, if you have any; that next time they hand you a wet NMR tube, you're going to smash it in their face. Thats what I do...seems to work
hypervalent_iodine Posted June 9, 2011 Posted June 9, 2011 Tell your underlings, if you have any; that next time they hand you a wet NMR tube, you're going to smash it in their face. Thats what I do...seems to work Given the hygroscopic nature of the product, I suspect it is the product that is contaminated with water more than it is the NMR tube.
mississippichem Posted June 9, 2011 Posted June 9, 2011 Given the hygroscopic nature of the product, I suspect it is the product that is contaminated with water more than it is the NMR tube. Yeah, I figured as much. Wet NMR tubes are just one of those things that make my blood boil. Even the possibility of such calls for a death atonement.
danaH Posted June 10, 2011 Author Posted June 10, 2011 heheh,,,,no need to get crazy....the water is from my compound,,,,the acetone is from the CDCl3 bottle
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