It is a famous reaction that used to be a teaching lab experiment, but is now banned in Germany, because it is too dangerous. To quote-translate quite liberally from the German www.seilnacht.com:
In a stone quarry near Zurich, Hermann Staudinger attempted to artificially produce a diamond by reacting the potassium-sodium melt with tetrachlorocarbon in a bomb tube. The attempt failed as the mixture tore the bomb tube apart.
In einem Steinbruch bei Zürich versuchte Hermann Staudinger einen Diamanten künstlich herzustellen, indem er die Kalium-Natrium-Schmelze mit Tetrachlorkohlenstoff in einem Bombenrohr reagieren ließ. Der Versuch misslang, da die Mischung das Bombenrohr zerfetzte.
I was probably one of the last students who were still able to see this experiment, and while considerably down scaling the actual set-up, it was still one of the most powerful explosions I ever witnessed.
To me it was actually surprising that I found pages, while researching this reaction, that asked whether CClX4 can act as a solvent in the Wurtz Reaction, or that in the Wurtz reaction of carbon tetrachloride and sodium no product would be formed, because CClX4 is too stable to react.
However, due to this I found the following passage in Inorganic Chemistry:
Tetrahaloalmethanes can be reduced by strong reducing agents, such as alkali metals. For example, the reaction of carbon tetrachloride with sodium is highly exoergic: CClX4(l)+4Na(s)⟶4NaCl(s)+C(s)ΔrG∘=−249 kJmol−1
This reaction can occur with explosive violence with CClX4 and other polyhalocarbons, so alkali metals such as sodium should never be used to dry them.
Unfortunately I reached a dead end with finding more literature about the reaction. I am especially interested in the mechanism, and the final products. I would assume that the above equation only represents a theoretical model, and the products will likely be carbon dioxide and other combustion related products. I'd be interested to know if there are any practical and/ or theoretical studies to the kinetics and thermodynamics of the reaction.
If the source does not cover tetra-, but tri-, or bihalogenated methane, I assume it is fine, too, but it should go beyond the Wurtz reaction (2R−Cl+2Na⟶R−R+2NaCl).
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