Organic Chemistry II Subscribe with Bloglines class wiki class vodcast

Saturday, July 02, 2005

Eco-Friendly Halogenation of Alkynes



This reaction is a summary of an ecologically friendly process for halogenating alkynes. The reaction works with both hydrobromic and hydrochloric acid, and produces water as its only waste product. It also gives a good yield of the halogenated product.
Instead of undergoing anti-Markovnakov addition of HBr, the alkynes are halogenated. This is due to the way the reactants are mixed. Mixing a hydrohalogenic acid with a solution of t-butylhydroperoxide (TBHP) and hydrogen peroxide will oxidize the halogens, causing them to become positively charged. The charged halogens will then attack the alkynes, and a halogenation reaction will occur.

For the full text of the article describing this process, see this report.

4 Comments:

  • 1) the link to the article is broken (end of text).
    2) use CiteULike at least once per post(see Yana' first post for how to do it correctly)
    3) This is not a reaction we looked at so explain a little more how it works - see start of article for hint. Normally peroxide and HBr give an anti-Markovnikov addition of HBr but this is a halogenation reaction, usually requiring Br2.

    By Blogger Jean-Claude Bradley, at 9:27 AM  

  • Your entry is good. You just need to put the CiteULike link and you are done.

    By Blogger Jean-Claude Bradley, at 8:15 PM  

  • Half marks: CiteULike link still missing after deadline

    By Blogger Jean-Claude Bradley, at 6:43 AM  

  • These reagents generate HOBr and t-BuOBr NOT a positively charged bromine atom. Also, organic peroxides (R-O-O-R)initiate free radical reactions not hydroperoxides.

    By Anonymous Anonymous, at 5:31 PM  

Post a Comment

<< Home