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Synthesize propyne

  1. Dec 1, 2014 #1
    I would like to know how to synthesize propyne from propane. I know there is a better answer (much better) than the one I put on my test. I said that propane should be exposed to a bromine solution in the presence of ultra violet light to create 2,2-dibromopropane. I then said to take this compound and expose it to a strong hindered base to create propyne via an E2 mechanism. What is the better way to synthesize propyne, or any allyne from an alkane for that matter? Thanks.
  2. jcsd
  3. Dec 1, 2014 #2


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    MgC2 + H2O → CH2=C=CH2 + CH3-C≡CH, alkylation of acetylene (from CaC2, or other sources).
  4. Dec 4, 2014 #3
    2,2 dibromopropane is a minor product. reason: after formation of 1-bromo propane the bromine acts as an electron withdrawing group and this destabilises the carbon radical for next bromination.
    Better way: use bromination first to give 2-bromo propane(major). now use alcoholic KOH for elimination to get propene.Now use Br2 in CCl4 for dihalogination and use base to get alkyne.
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