turd
National Hazard
Posts: 800
Registered: 5-3-2006
Member Is Offline
Mood: No Mood
|
|
Drying DMSO with sodium
Don't do it.
Actually don't dry any oxidiser with a reducer or vice-versa. But never, never, NEVER try to dry DMSO with molten sodium.
I just was really close to blowing myself up doing this. When I had finished preparing an ice bath there were already sparks in the mix!! 
|
|
|
garage chemist
chemical wizard
Posts: 1803
Registered: 16-8-2004
Location: Germany
Member Is Offline
Mood: No Mood
|
|
Same with DMF and sodium, the reaction is even more violent and nasty, and generates carbon monoxide.
I made a thread about this a while back. Glad that I only used about 5ml DMF.
|
|
|
BromicAcid
International Hazard
Posts: 3227
Registered: 13-7-2003
Location: Wisconsin
Member Is Offline
Mood: Rock n' Roll
|
|
What would even make you think to do such a thing? I mean, yeah... sodium is used to dry a lot of things, but the reaction of sodium with DMSO
readily forms the dimsyl anion (although sodium hydride is preferred) and most firmilar with DMSO are knowledgeable of this reaction. Supposedly
there is no noticeble reaction with lithium though, at least at room temperature.
What exactly happened? DMSO can be dried over sodium or potassium hydroxide given enough time.
|
|
|
turd
National Hazard
Posts: 800
Registered: 5-3-2006
Member Is Offline
Mood: No Mood
|
|
| Quote: | | What would even make you think to do such a thing? |
Something like this: CaH is a recommended drying agent, and Na is considered to be of about the same potency, so it should be ok. Somewhere else I
read that they distilled DMSO from sodium, so 70-80°C should be ok and if that is ok, one can heat it just a bit more, to avoid cutting the sodium
and to look at those funny metal bubbles. Ok, ok, I admit it, it was the funny bubbles that made me do it. 
| Quote: | | What exactly happened? |
At first not much, the solution became yellow, which is not out of the norm when drying with sodium. But when the sodium started melting, the solution
suddenly became very dark and started emitting white fumes. I thought darn it and removed the heat, but it would not calm down, so I prepared an ice
bath and when I came back, there were sparks and nasty brown fumes. The ice-bath helped and the solid residue with finely dispersed sodium was killed
with n-PrOH. So maybe I wasn't close to blowing myself up, but seeing sparks in a sodium/solvent mix was pretty scary.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
