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Homework Help: Alcoholos and nucleophilic subst.

  1. Dec 12, 2007 #1
    i was doing some revision and i wondered whether alcohols can be made from nucleophilic substitution reactions of halogeno alkanes.

    e.g.: ethylchloride + OH- -------> ethanol + Cl-

    i know the reverse works. halogeno alkanes are formed via nucleophilic substitution reactions. but what about alcohols being formes through this mechanism too.

    nothing is said about it in my text book.
  2. jcsd
  3. Dec 13, 2007 #2


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    Kushal, this is a known reaction to produce alcohols. I'm not so sure about the reverse reaction... hydroxide is a terrible leaving group. Acid-catalyzed reactions are possible with primary alcohols but secondary, and especially tertiary alcohols, undergo elimination under these conditions.

    Alcohols are usually converted into another group to make them suitable for nucleophilic displacement. The reagents to do this include triflate, anhydrides of carboxylic acids, organo sulfonates (espescially tosylate), organo phosphorus compounds and other more exotic species. The upshot is that hydroxide is such a bad leaving group (for nucleophilic displacement) that they must be substituted with strongly electron withdrawing groups to make it happen.

    Good luck on your tests.
    Last edited: Dec 13, 2007
  4. Dec 13, 2007 #3
    aa.....ok.....i never knew this about hydroxides....
    thnks for the tip
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