sonoferos
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CCl2F2 substituted for H3N for reduction of Li
Can CCl2F2 be used to reduce Li for a birch instead of H3N?
And, if so, what would be the diffrence in the handling of the ccl2f2?
Any thoughts on this?
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12AX7
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Reduce Li??? With a halide? The only thing that would happen is the Li grabs the Cl and possibly F off the carbon! It may not be spontaneous at
room temp, but it will be energetic!
As I understand it, a Birch reduction involves NH3 (what is H3N exactly) as a solvent for the alkali metal.
Tim
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JohnWW
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Li metal is already "reduced", so the question does not make sense at all, really. However, addition of H to a compound is generally regarded as a
form of "reduction", so the only way Li metal could be further "reduced" is by formation of LiH, by direct reaction with H2 in the absence of air and
H20. With liquid NH3, alkali metals, depending on the temperature and pressure and the metal, can either be "solvated" with the electron given up to
NH3 molecules (probably in an anti-bonding orbital), or else would react to form mostly the ionic amides (NH2-) and imides (NH--), with possibly some
nitride also formed.
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ziqquratu
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@ JohnWW: Adding a H is only considered reduction in organic chem. If you think about it - LiH is lithium hydride, meaning Li+ H-. So from H2 to H- is
reduction, and Li to Li+ is oxidation.
I think that the whole thing with the Birch type reductions is those solvated metal species you mention. I cant remember for certain right now, but I
believe that the reaction is through electron transfer from the metal to the species to be reduced, and that the amine solvent stabilises the radicals
formed in the process.
Beyond that, I remember some discussion about using primary amines as solvents for these reactions, to replace liquid ammonia, but I cant remember if
those discussions concluded that it does work, or that it doesnt.
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