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Maggie Geselbracht, Reed College
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Joined: 11/17/2007 - 11:00am

Deuterated solvents and glove boxes

Another glove box question from a "formerly dry box-now working with a few solvents in the box" neophyte...

We want to make up some NMR samples in the glove box and want to know if there are any special precautions we should worry about in working with the deuterated solvents?  The deuterated solvents that we will be using include d8-iPrOH, d6-benzene, d6-acetone, and CDCl3.  The only other solvent we have in the box right now is a 1-L Sure-seal bottle of anhydrous iPrOH and a 1-L Sure-seal bottle of propylene carbonate.

Adam R. Johnson, Harvey Mudd College
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Joined: 11/17/2007 - 10:55am
The big concern is not so much getting the NMR solvents in your glovebox, but getting the other solvents from your box into the deuterated solvents.  Our NMR spectra are usually done in 1-5 mol% diethyl ether...  If you don't have volatile solvents in the box, no big worry.  For the halogenated solvents (CDCl3), you should turn off your circulator while using it, and then purge for 10-20 mintues with the circulator off before restarting.  This prevents halides interacting with the CuO/Cu catalyst and irreversibly ruining it.  To be honest, making up 1 NMR tube worth of CDCl3, I wouldn't worry so much about it.  Purging, by the way, refers to blowing most of the atmosphere out of the box.  I have a valve on the side that I can open.  I set the pressure way up high, open up the valve, and hope for laminar flow (ha ha ha)

I dry my deuterated Benzene rigorously (we go through 20-50 g per semester or more) from Na/Benzophenone followed bye 3 freeze-pump-thaw cycles. 
don't use CDCl3 in the box very much
thf, CD2Cl2, I tend to purchase high quality ampules from Cambridge Isotope Labs and use them as they come.  you can probably do the same.  If your stuff is air sensitive, but not protic sensitive (I'm guessing from iPrOH on this one) you should probably do a couple FPT cycles before use.

I keep my deuterated solvents in a storage "bomb" that I only open rarely, and take 10-20 mL out and store that in a 20 mL vial.  Keeping solvent vapors from the main storage supply as much as possible.
By the time you get to the bottom though, its 10% ether.  if you only have non-volatile solvents, or deuterated solvents in your box, its not much of a worry.
Nancy Scott Burke Williams, Scripps College, Pitzer College, Claremont McKenna College
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Joined: 11/17/2007 - 10:57am
I generally don't worry about deuterated solvents in the box, like Adam. The amount that is going to end up in your catalyst is really small. But he's right-closing the cat and purging for chlorocarbons (and nitriles, phosphines, and sulfides) is really good practice if you're doing something other than opening a bomb to syringe out 500 uL of CD2Cl2. I don't have as much trouble with solvents in the box getting into our NMR solvents, probably because we (a) do less wet chemistry in the box, (b) purge after major solvent parties, and (c) keep our solvents in pretty well-closed bottles that leak remarkably little (I've discovered year-old pentane bottles with plenty of liquid in them). Wrapping bottle threads with TFE tape (or, better yet, using bombs) can cut down on that problem.
Adam R. Johnson, Harvey Mudd College
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Joined: 11/17/2007 - 10:55am

You and I both know that "bombs" are glass vessels with Teflon valves, but I know that there is a movement afoot to change the name of that piece of glassware to a "valved reaction vessel" or "valved storage vessel."  VRV or VSV just doesn't roll off the tongue like "bomb" though.  And, I have a drawer in my lab labeled "bombs" so I hope Homeland Security doesn't come visit.

We need a marketing team to come up with a good acronym or name or something.

Nancy Scott Burke Williams, Scripps College, Pitzer College, Claremont McKenna College
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Joined: 11/17/2007 - 10:57am

Great. Just great. Now are we supposed to do valved reaction vessel calorimetry? Will the military begin dropping valved reaction vessels on countries that have pissed us off? I just can't wait until we have to evacuate the building during a big exam because of a valved reaction vessel threat. The valved reaction vessel squad and the valved reaction vessel sniffing dogs will probably make more money (or at least be fed better dog chow) because their job title will have more syllables. What's the world coming to?

 I know, I know...I should just go write my exam...er...student learning outcomes assessment instrument.

araz, Koc university
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Last seen: 5 years 2 months ago
Joined: 12/01/2012 - 9:57am

 

Hi all,

I recently join to this website which seems quite interesting and informative website. I am afraid my question can be a bit off topic but I decide to post it in this topic which seems similar to my question.

I want to use diethyle ether inside of glove box. I just want to pure it in to ball mill vial and close it fast. Then, I want to take out balls from the solution after ball mill is done which might take at most 10 min.

 I have read something about it and I found that there is not any problem with using it. But still I am not sure about complete procedure .

I wonder that how much diethyle ether is allowed to inter to N2 filled glove box? 50 ml or 100 ml? how long can I keep working with it inside of glove box? And during working should I keep circulation valve close? After finishing my work what should I do exactly?

Thanks for your supports

Araz

Kyle Grice, DePaul University
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Joined: 07/22/2010 - 5:29pm

We could start a new thread on solvents in gloveboxes in general.

I agree with what Adam and Scott already said. If you are working with a solvent open in a glovebox, especially something highly volatile like diethyl ether, be sure to keep everything else tightly capped. When you are done with the Et2O and have brought all of the glassware/supplies that have ether on them out of the box, purge for a long time when you are done.  Ether won't hurt really your catalyst, the biggest problem you will have is contamination of other solvents/liquids if they are not sealed. This relates back to the NMR solvent issue, any NMR solvents you have in the box will have ether in them.

We had that problem in a box here in my postdoc lab, someone used warm toluene open in the box and didn't have everything else closed and didn't purge long enough afterwards...sure enough, you see toluene in all of the NMR solvents that were in that box.

If you can get a bunch of teflon stopcock sealable vials (The "bombs" Adam and Scott referred to - chemglass's AF 0523 or similar), those work really well for keeping NMR solvents and solvents/liquid reagents in general well-sealed.

Again, purging before (especially if you were working with something else volatile earlier in the day/week) and after opening any solvents/liquids is something that should always be done in a box to reduce cross-contamination.

-Kyle

Fernando Sterea, AngraPorto, RJ, Brazil
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Joined: 10/31/2013 - 9:40pm

@Adam R. Johnson, makes real sense! I did exactly what you told and it worked as a charm. Thanks for the info!

Fernando Sterea