In discussing how best to deuterate chloroform, it occurred to me that we could use sodium metal to reduce hydrogen into hydrogen gas. If this could actually happen, this would be a great thing - we wouldn't have much if any residual hydrogen in the liquid phase of the system after treatment.

Is this possible? I had a possible mechanism in mind.

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The problems I foresee are:

1) Won't reduction of chlorine to chlorine gas be a competitive, side reaction? From this page (http://en.wikipedia.org/wiki/Standard_electrode_potential_(data_page)) I see that the reduction potential for chloride ion to to chlorine gas is -1.36 V (unfavorable) and reduction of hydride ion to hydrogen gas is a +2.23 V (favorable). Am I interpreting and applying the data correctly?

2) What happens to the $\ce{CCl_3}$ radicals after hydrogen is reduced? Is dimerization going to occur to a large extent?

3) How then do we introduce deuterium and effectively incorporate it with $\ce{CCl_3}$ radicals?

  • 2
    $\begingroup$ The charges don't balance in your first mechanistic step. There has to be an anion produced... $\endgroup$
    – jerepierre
    Sep 16 '14 at 0:18
  • $\begingroup$ @jerepierre I see what you're saying, there should be a hydride anion. Thank you! $\endgroup$
    – Dissenter
    Sep 16 '14 at 0:21
  • $\begingroup$ Do not for goodness sake mix chloroform and sodium metal, it can explode. $\endgroup$ May 5 '18 at 5:45

Sodium + Chloroform: https://www.youtube.com/watch?v=du3ksrfnCcg

To prepare deuterochloroform I'd recommend the haloform reaction.

  • $\begingroup$ That was very, very interesting! Thank you for sharing! Perhaps the reaction can be controlled? After all the use of sodium isn't unheard of in the lab. Also the gas produced sure didn't look like chlorine gas and probably wasn't given that there were students a few feet away. Perhaps it is H2 gas. $\endgroup$
    – Dissenter
    Sep 16 '14 at 0:10

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