1 Dr. Marwa Eid

2 Amines Derivatives of ammonia, NH 3. Contain N attached to one or more alkyl or aromatic groups.

3 Classification of Amines Amines are classified as primary, secondary, or tertiary. In a primary (1°) amine, one carbon group is bonded to the nitrogen atom. A secondary (2°) amine has two carbon groups bonded to the nitrogen atom. A tertiary (3°) amine has three carbon groups bonded to the nitrogen atom. H CH 3 CH 3 | | | CH 3 —N—H CH 3 —N—H CH 3 —N—CH 3 1° 2° 3°

Naming simple amines Simple 1º amines are named as “alkylamine” – Examples: methylamine CH 3 NH 2 ethylamine CH 3 CH 2 NH 2 butylamine CH 3 CH 2 CH 2 CH 2 NH 2 Symmetrical 2º or 3º amines are named as “dialkylamine” or “trialkyamine ” – Examples : diethylamine (CH 3 CH 2 ) 2 NH; trimethylamine (CH 3 ) 3 N

5 Naming Amines CH 3 —CH 2 —NH 2 Ethylamine CH 3 —NH—CH 3 Dimethylamine CH 3 | CH 3 —N—CH 2 —CH 3 Ethyldimethylamine

6 Aromatic Amines The amine of benzene is named aniline. Alkyl groups on the N use the prefix N- with alkyl name. aniline 3-chloroaniline methylaniline

7 Learning Check Give the common name of each compound. A. CH 3 —NH—CH 2 —CH 3 CH 3 | B.CH 3 —CH 2 —N—CH 2 —CH 3 C.

8 Solution A.CH 3 —NH—CH 2 —CH 3 ethylmethylamine CH 3 | B. CH 3 —CH 2 —N—CH 2 —CH 3 diethylmethylamine C. aniline

9 Learning Check Write the structural formula for A. methylpropylamine B. 2-chloroaniline

10 Solution A. methylpropylamine CH 3 –CH 2 –CH 2 –NH–CH 3 B. 2-chloroaniline

TO BE CONTINUED…..

12 Hydrogen Bonding for Amines The N − H bond provides hydrogen bonding in 1°and 2° amines, but not in 3° amines. is not as polar as the O-H bonds in alcohols.

13 Solubility in Water Amines With 1-6 carbon atoms are highly soluble in water. Form hydrogen bonds with the polar O-H bond in water.

14 Learning Check Consider the following compounds. 1) CH 3 —CH 2 —CH 2 —NH 2 2) CH 3 —CH 2 —NH—CH 3 3) CH 3 —CH 2 —CH 2 —CH 3 A. Which compound has the highest boiling point? B. Which compound is soluble in water?

15 Solution Consider the following compounds. 1) CH 3 —CH 2 —CH 2 —NH 2 2) CH 3 —CH 2 —NH—CH 3 3) CH 3 —CH 2 —CH 2 —CH 3 A. Which compound has the highest boiling point? 1) CH 3 —CH 2 —CH 2 —NH 2 B. Which compound is soluble in water? 1) CH 3 —CH 2 —CH 2 —NH 2 2) CH 3 —CH 2 —NH—CH 3

16 Amines are weak bases in water. CH 3 —NH 2 + H 2 O CH 3 —NH OH – methylammonium hydroxide (amine salt) Amines React as Bases

17 An amine salt forms when an amine is neutralized by acid. is named by replacing the amine part of the name with ammonium, followed by the name of the negative ion. CH 3 —NH 2 + HCl CH 3 —NH 3 + Cl – methylamine methylammonium chloride chloride Neutralization Forms Amine Salts

18 Properties of Amine Salts Amine salts are solids at room temperature. soluble in water. used for drugs.

19 Alkaloids Alkaloids are a group of naturally occurring chemical compounds that contain nitrogen. obtained from plants. used as anesthetics, antidepressants. Example of alkaloids are Morphine and Codeine