Amines, Organic Derivatives of Ammonia

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Amines are organic derivatives of ammonia, meaning that one, two, or three hydrocarbon groups have replaced the hydrogens in ammonia. The simplest ones are: 
  H
  |
H-N-H
ammonia
 
    H
    |
CH3-N-H
methylamine
 
    H
    |
CH3-N-CH3
dimethylamine
 
    CH3
    |
CH3-N-CH3
trimethylamine
The NH bond is not as polar as the OH bond in alcohols, so amines boil at lower temperatures than alcohols of comparable molecular masses. Amines which have low molecular masses are soluble in water because of hydrogen bonding. This is also why trimethylamine has a lower boiling point than dimethylamine (even though its bigger), becuase there is no NH bond to cause significant hydrogen bonding.

Basicity and Reactions of Amines

Like ammonia, amines are Brønsted bases (proton acceptors) because of the nitrogen. In water, this equilibrium will exist: 
       H                       H
       |                       |+
CH3CH2-N-CH3 + H2O <==> CH3CH2-N-CH3 + OH-
                               |
                               H

ethylmethylamine + water <==> ethylmethylammonium ion + hydroxide ion
Because of reactions similar to above, aqeous solutions of amines are basic and therefore have pH values above 7.
When mixed with a strong proton donor like hydrochloric acid, amines change almost entirely into its protonated form by accepting a proton. 
       H                      H
       |                      |+
CH3CH2-N-CH3 + HCl ==> CH3CH2-N-CH3 + Cl-
                              |
                              H
When water-insoluble amines give this reaction, they can become more soluble because they have been changed into ions that can be hydrated by water.
Once amines have become protonated, they act as weak Brønsted acids and can neutralize a strong base by reversing the protonation.
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