[alphahydroxy]

Hi.

Just wondering if anyone has any experience with NMP (that is, N-methylpyrollidinone, a dipolar aprotic solvent). I'm going to distill some at some point soon (I need it dry, and I'm starting to worry about the sure-seal...) and I'm hoping someone knows the best way to do it?

My plan as it stands is just to vacuum distill fromcalcium hydride onto molecular sieves, but I'm open to better ideas...

Cheers

[movies]

The lab purification book we use says that you can just azeotrope off the water with benzene.

If you really want to distill it, I hope you have a good vacuum.

[alphahydroxy]

hmmmm.... well i can't really be arsed messing around with azeotropes and running the possiblity of contaminating my solvent. I'm also not massively keen on using benzene at the best of times!

I'm sure the house vacuum is strong enough to pull NMP over at a reasonable temp anyway.

I'll have another route through the books....

[movies]

Benzene isn't all that bad as long as you are careful.  The benzene will boil out well before the NMP.  NMP boils at about 202 degrees C, benzene at 80 degrees C.  If you have a rotovap it should be no problem.

I doubt I could pull off NMP using my rotovap and our house vac without some serious heating.  I can pull off something like DMF (bp ~153 degrees C) with my water bath at about 35 degrees C.

If you can find another way though....

[alphahydroxy]

If you can pull DMF off at 35 degrees then NMP shouldn't take more than about 80 ?  That's what my nonograph tells me anyway... a little dubious, but not too bad!

I think I'd rather distill than use a rotovap cos then I can store it over sieves and can keep everything under vac or N2 at all times...

I'm thinking my sure-seal may be more robust than I've given it credit for so maybe I'll be leaving the distillation for a while anyway.

Cheers

[movies]

In our lab, every time we use a sure seal we cover the top with some heavy duty sticky tape (not just Scotch tape) and it seems to extend the lifetime considerably.

[alphahydroxy]

hmmm.... interesting.

Do you mean like electrical tape or something more like packing tape?

[movies]

I don't know what to compare it to.  It's kind of the same thickness as electrical tape, but it's clear and it doesn't get slimy the way electrical tape does after a while.  We get it from 3M, but I have no idea what it's called or anything.  We just call it "sticky tape."