1. Chemistry 20
Chapter 8
Amines

2. Amines Amines: Are derivatives of ammonia NH3.
Contain N attached to one or more alkyl (Aliphatic amine) or aromatic groups (Aromatic amine).
CH3-NH CH3-NH-CH3
-NH2 amino group
NH2

3. Amines Amines are classified into three groups:
depending on the number of carbon groups bonded to nitrogen.
CH CH3
 
CH3—NH2 CH3—NH CH3—N—CH3
Primary 1°
Secondary 2°
Tertiary 3°

4. Naming Amines IUPAC name – 1° amines
The same method as we did for alcohols.
- Drop the final “-e” of the parent alkane and replace it by “-amine”.
- Use a number to locate the amino group (-NH2) on the parent chain.
CH3-CH-CH3
NH2
CH3-CH-CH-CH3
NH2 Cl 3 5 3 1 6 4 2 1 3 2 2 1 4
2-propanamine
3-chloro-2-butanamine
1,6-hexanediamine

5. Names of alkyl groups (In alphabetical order) + “amine”
Naming Amines
Common name
Names of alkyl groups (In alphabetical order) + “amine”
CH3—CH2—NH2 ethylamine
CH3—NH —CH3 dimethylamine
CH3 |
CH3—N—CH2—CH3 ethyldimethylamine

6. Aniline (common name) NH2 Aniline NH2 NH2 NH2 CH3 CH3 Cl NO21 1 1 2 3
CH3 3 3 4
CH3 4 Cl
NO2
4-Nitroaniline
3-Methylaniline
4-Chloro-3-methylaniline

7. Naming Amines IUPAC name – 2° and 3° amines aniline CH3 CH3-N-CH2-CH3
Take the largest group bonded to nitrogen as the parent amine.
Name the smaller group(s) bonded to nitrogen, and show their locations on nitrogen by using the prefix “N”.
aniline
CH3-N-CH2-CH3
CH3
N,N-Dimethylethanamine

8. Heterocyclic amines When N is one of the atoms of a ring. Pyrrolidine
CH3
Pyrrolidine
Pyridine
Nicotine

9. Physical properties of Amines
They have unpleasant odors (rotting fish like ammonia).
They are polar compounds.
Difference in electronegativity between N - H (3.0 – 2.1 = 0.9)
3. 1° and 2° amines have hydrogen bonds (N-H).
Weaker than alcohols (O-H).
3° amines do not form hydrogen bonds (no H atom).
Boiling points: Hydrocarbons< Amines < Alcohols
Almost soluble in water (hydrogen bonding).

10. . Chemical properties of Amines
They are weak bases (like ammonia): react with acids.
(to form water-soluble salts) N H
CH3 . +
H – O – H
O – H -
Some amines present in our blood and make it approximately basic (pH = 7.4).

11. Chemical properties of Amines
Aliphatic amines are weak bases by comparison with inorganic bases
such as NaOH, they are strong bases among organic compounds.
Aliphatic amines are stronger bases than aromatic amines.
(slightly stronger than NH3)

12. Examples
Complete each acid-base reaction and name the salt formed.

13. Complete each acid-base reaction and name the salt formed.
Examples
Complete each acid-base reaction and name the salt formed.
Solutions: