The Naked Scientists

The Naked Scientists Forum

Author Topic: I want an amine from a haloalkane, why does the ammonia have to be alcoholic?  (Read 4151 times)

Offline Chemistry4me

  • Neilep Level Member
  • ******
  • Posts: 7709
    • View Profile
Seeing as this board has been quite quiet lately, and also to help out our dear friend, I have this question:

In order for a haloalkane to form an amine, the ammonia it reacts with is dissolved in alcohol, why must the solvent used for the reaction be alcohol and not water?

Is it simply that an effective solvent must dissolve the reagents, and a simple haloalkane is not going to be very water soluble? Or is there something else?


 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8670
  • Thanked: 42 times
    • View Profile
There are two possible reasons and both play a part.
As you say, the reaction is going to work a whole lot better if the reactants mix and most haloalkanes have rather low solubillities in aqueous solutions.
A second point is that haloalkanes react with water. The reaction is generally slow (though it's faster in the presence of hydroxide ions which may be formed in a solution of ammonia or an amine).
The alcohol formed by the side reaction is both a waste of alkyl halide and also an impurity that you need to remove from the product.
 

The Naked Scientists Forum


 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums