Amines (R-NH2)
The amine family contains the amino group (-NH2) at the end of a hydrocarbon chain.
Amines are based on ammonia (NH3).
When organisms decompose, protein breaks down into amines, which have unpleasant odours. Putrescine and cadaverine are the amines found in decomposing animal tissue.
Physical Properties of the Amines
Amines have higher melting points and boiling points than hydrocarbons of equivalent size and the smaller amines are water soluble.
There are two types of polar bonds, the N-C bonds and any N-H bonds, which increase the intermolecular forces of attraction.
Since N-H bond is not as polar as -OH bond, amines have lower melting/boiling points than analogous alcohols.
Amines are organic bases and have all the properties of bases.
Amides
The amide linkage is very important in biology – it forms the backbone of protein molecules. In proteins, the amide linkages are called peptide bonds.
Properties
of Amides
The smaller amide are water soluble since the polar N-H bonds can H-bond with water.
Preparing Amides
Amides are formed by the reaction of a carboxylic acid with an amine in a condensation reaction.
Homework:
Practice, p. 230 #1-5
Answers:
