Sciencemadness Discussion Board

is lah soluble in dcm?

Furboffle - 9-11-2012 at 10:51

Can lah reduction be carried out in DCM?
I've seen one vague comment on another forum saying its possible but i cant refind the link. it had no source. I haven't been able to find articles or qualitative data regarding solubility in chlorinated solvents. Being aprotic I would expect potential but that's not definitive...

bfesser - 9-11-2012 at 20:19

More of <a href="http://www.sciencemadness.org/talk/viewthread.php?tid=22119#pid264514">this</a>?

[edited to remove grumpiness]

Why do you want to carry out your reduction in DCM? What are you trying to reduce?

[Edited on 11/10/12 by bfesser]

Hexavalent - 10-11-2012 at 07:11

No one who initializes LiAlH4 as 'lah' should even have access to such powerful and reactive chemicals.

http://www.chem.ed.ac.uk/safety/resources/notices/solvents.p...

suggests that mixing LAH and chlorinated solvents is a bad idea.

Most of what I've read in the last five minutes seems to favour THF as a solvent. Why can this not be used for your reduction?

Furboffle - 10-11-2012 at 15:04

I'm reducing an amide. I have no intention of using DCM as I have THF readily available. This is more for curiosity's sake. as both are easily attainable, THF as far as I've found is cheaper so why opt for DCM when it costs slightly more than the stuff that is typically the "ideal" solvent involving LAH.

I've just been taught and always see either using ether or THF(which is still an ether) in conjunction with LAH... but as an aprotic solvent is the key just wondered how does say DCM or chloroform play into being the solvent used.
Quote: Originally posted by Hexavalent  
http://www.chem.ed.ac.uk/safety/resources/notices/solvents.p...

I guess this hints at there being an issue but doesn't explain anything. I'm curious about the theory behind it. Would it be possible for LAH to attack the halides in the same way that it would attack water? perhaps something like this
LiAlH4 + 2 CH2Cl2 -> LiCl + AlCl3 + 2CH4