1. Amines are organic derivatives of ammonia, NH3
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.1
Introduction
Amines are organic derivatives of ammonia, NH3
Classification of Amines
Primary amines
Secondary amines
Tertiary amines

2. Classify the following amines:
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.1
Classify the following amines: 1° 2°
Aliphatic amines 3° 2° 1°
Aromatic amines 3°

3. Chapter 19 : Amines 19.1 : Introduction 19.4 : Preparation 19.2
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.2
IUPAC Nomenclature
In primary amines, the suffix ‘amine’ replaces the ‘e’ in the name of the parent alkane
propan e
amine e
Secondary and tertiary amines are named as N-substituted derivatives of primary amines 2°
N-methyl
ethan e
amine e

4. N-ethyl-N-methyl ethanamine
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.2
Examples:
Structure
IUPAC Name
Methanamine
2-propanamine
Cyclopentanamine
N-methylpentanamine
N-ethyl-N-methyl ethanamine

5. Chapter 19 : Amines 19.1 : Introduction 19.4 : Preparation 19.2
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.2
IUPAC Nomenclature
When multiple functional groups are present and the –NH2 group does not take priority, it is named as an “amino” substituent
Examples:
2-amino
ethanoic acid 4 1
2,4-diamino
phenol 3 2

6. Aromatic amines are named as derivatives of aniline
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.2
IUPAC Nomenclature
Aromatic amines are named as derivatives of aniline
N-ethyl-N-methylaniline

7. Most primary amines are named as alkylamines Structure IUPAC Name
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.2
Common Name
Most primary amines are named as alkylamines
Structure
IUPAC Name
methylamine
ethylamine
propylamine
dimethylamine
methylethylamine

8. Tertiary amines cannot form hydrogen bonds to each other.
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.3
(i) Boiling Point
Both primary and secondary amines can form intermolecular hydrogen bonds.
Boiling point
Solubility
Basicity
1° amines
3° amines
2° amines
Tertiary amines cannot form hydrogen bonds to each other.

9. Relative molecular mass
Examples:
The table below compares the boiling points of isomeric amines.
Amines
Class
Relative molecular mass
Boliling points/oC
CH3CH2CH2NH2 1° 59 49
CH3CH2-NH-CH3 2° 37
CH3 |
CH3-N-CH3 3° 4
Boiling Point : CH3CH2CH2NH2 > CH3CH2NH(CH3) > (CH3)3N

10. intermolecular hydrogen bonding
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.3
(i) Boiling Point
Amines have higher boiling points than alkanes or haloalkanes of similar relative molecular mass due to
Boiling point
Solubility
intermolecular hydrogen bonding
Example
Basicity
Amines have lower boiling points than alcohols or carboxylic acids of comparable molecular weight because
H- bond in RNH2 is weaker than the
H- bond in ROH and RCOOH
(Nitrogen is less electronegative than the Oxygen)

11. Relative molecular mass
Examples:
The table below compares the boiling points of organic compounds of comparable relative molecular mass.
Amines
Type
Relative molecular mass
Boliling points/oC
CH3CH2CH2CH3
butane
CH3CH2Cl
chloroethane
CH3CH2CH2NH2
1-propanamine
Alkane 58
-0.5
64.5
12.5
Haloalkane 59
48.6
Amine

12. intermolecular hydrogen bonding
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.3
(i) Boiling Point
Amines have higher boiling points than alkanes or haloalkanes of similar relative molecular mass due to
Boiling point
Solubility
intermolecular hydrogen bonding
Example
Basicity
Amines have lower boiling points than alcohols or carboxylic acids of comparable molecular weight because
H- bond in RNH2 is weaker than the
H- bond in ROH and RCOOH
(Nitrogen is less electronegative than the Oxygen)
Example

13. Relative molecular mass
Examples:
The table below compares the boiling points of organic compounds of comparable relative molecular mass.
Amines
Type
Relative molecular mass
Boiling points/oC
CH3CH2CH2CH3
butane
CH3CH2Cl
chloroethane
CH3CH2CH2NH2
1-propanamine
Alkane 58
-0.5
64.5
12.5
Haloalkane
CH3CH2CH2NH2
1-propanamine 59
48.6
Amine
CH3CH2CH2OH
1-propanol
Alcohol 60
97.2
CH3COOH
ethanoic acid
Carboxylic acid 60
118
Boiling Point : Carboxylic acid > Alcohol > Amine > Haloalkane > Alkane

14. Chapter 19 : Amines 19.1 : Introduction 19.4 : Preparation 19.3
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.3
(ii) Solubility
Boiling point
All amines including tertiary amines, are capable of forming hydrogen bonds with water molecules. Thus simple amines (amines of fewer than 5 carbons) are generally water soluble and dissolve to form basic aqueous solutions
Solubility
Basicity

15. Comparison the solubility between 1°,2° and 3°amine
3° < 2 ° < 1 °
Increasing solubility
: hydrogen bonds
3 hydrogen bonds per a 1° amine molecule
2 hydrogen bonds per a 2° amine molecule
1 hydrogen bond per a 3° amine molecule

16. Chapter 19 : Amines 19.1 : Introduction 19.4 : Preparation 19.3
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.3
Basicity
An amine is a nucleophile (a Lewis base) because its lone pair of non-bonding electrons on nitrogen
Boiling point
Solubility
Basicity
Ammonia
Ammonium ion

17. Basicity – (i) Inductive effect An alkyl group is electron donating
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.3
Basicity – (i) Inductive effect
An alkyl group is electron donating
group, and it stabilises the
alkylammonium ion by dispersing its
positive charge
Boiling point
Solubility
Basicity
1° Amine
alkylammonium ion
Stabilised by the alkyl group
Stronger base

18. Increasing Chapter 19 : Amines 19.1 : Introduction 19.4 : Preparation
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.3
Boiling point
Solubility
1° Amine
alkylammonium ion
Basicity
2° Amine
alkylammonium ion
Strength as a base : Methyl, 1°, 2°
Increasing

19. Basicity – (ii) Resonance effect
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.3
Basicity – (ii) Resonance effect
Aromatic amines (e.g., aniline) are weaker bases than the corresponding aliphatic and cyclic amines
Boiling point
Solubility
Basicity
Example:
Cyclohexylamine Aniline
pKb = pKb = 9.42

20. Basicity – (ii) Resonance effect Aromatic amines are less basic
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.3
Basicity – (ii) Resonance effect
Aromatic amines are less basic
Boiling point
The lone pair electrons of nitrogen atom are delocalised and overlapped with the aromatic ring π electrons system make it less available for bonding to H+
Solubility
Basicity
arylamines are stabilised due to the 4 resonance structures

21. Hoffmann’s degradation of amides
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.4
Reduction of nitro compounds
Aromatic amines can be prepared by reduction of nitro compounds using Zn/H+ or SnCl2/H+
Reduction of
nitro compound
Reduction of nitriles
Zn/H+ or
SnCl2/H+
NO2
NH2
Reduction of amides
nitrobenzene
Aniline
anline
Hoffmann’s degradation of amides

22. Hoffmann’s degradation of amides
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.4
Reduction of nitriles
Nitriles are reduced to primary amines by H2 / catalyst, LiAlH4 / H+ or
NaBH4 / H+.
Reduction of
nitro compound
Reduction of nitriles
Reduction of amides
Example :
Hoffmann’s degradation of amides

23. Hoffmann’s degradation of amides
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.4
Reduction of amides
Reduction of an amide using LiAlH4 / H+ or NaBH4 / H+ can yield a primary, secondary, or tertiary amine depending on the type of amide used
Reduction of
nitro compound
Reduction of nitriles
Reduction of amides
Hoffmann’s degradation of amides

24. Hoffmann’s degradation of amides
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.4
Example :
Reduction of
nitro compound
Reduction of nitriles
Reduction of amides
Hoffmann’s degradation of amides

25. Hoffmann’s degradation of amides
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.4
Hoffmann’s degradation of amides
On warming a primary amide with bromine in solution of NaOH, a primary amine is formed.
This reaction is used to synthesise primary alkyl and aryl amines.
Reduction of
nitro compound
Reduction of nitriles
Reduction of amides
Hoffmann’s degradation of amides
The elimination of carbonyl group is shortening the length of carbon chain by one carbon atom.

26. Hoffmann’s degradation of amides
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.4
Example :
Reduction of
nitro compound
Reduction of nitriles
Reduction of amides
Hoffmann’s degradation of amides

27. Benzenesulphonyl chloride
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.5
Reaction with acyl chlorides
Reaction with :
1° and 2° amines are acylated to form N-substituted amides
Acyl chloride
Acid anhydride
Benzenesulphonyl chloride
Nitrous acid
Bromine water
3° amines are not acylated because they do not have a H atom attached to N atom.
Formation of dye

28. Benzenesulphonyl chloride
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.5
Reaction with acid anhydride
Reaction with :
1° and 2° amines are acylated to form N-substituted amides
Acyl chloride
Acid anhydride
Benzenesulphonyl chloride
Nitrous acid
Bromine water
3° amines are not acylated because they do not have a H atom attached to N atom.
Formation of dye

29. Benzenesulphonyl chloride
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.5
Reaction with benzenesulphonyl chloride
Reaction with :
Hinsberg’s test
Acyl chloride
This reaction is used to differentiate between 1°, 2° and 3° amines.
Acid anhydride
Benzenesulphonyl chloride
Nitrous acid
Bromine water
Formation of dye

30. Benzenesulphonyl chloride
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.5
1° amines
Benzenesulphonyl chloride reacts with a 1° amine to form a white precipitate (N-substituted sulphonamides)
Reaction with :
Acyl chloride
Acidic hydrogen
Acid anhydride
Benzenesulphonyl chloride
Nitrous acid
Bromine water
N-substituted sulphonamides have an acidic hydrogen, N-H.
Formation of dye
Therefore, it dissolve in aqueous NaOH.

31. Benzenesulphonyl chloride
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.5
2° amines
Benzenesulphonyl chloride reacts with a 2° amines to form a white precipitate (N,N-disubstituted sulphonamide)
Reaction with :
Acyl chloride
Acid anhydride
Benzenesulphonyl chloride
Nitrous acid
Bromine water
N,N-disubstituted sulphonamides do not have an acidic hydrogen, N-H.
Formation of dye
Therefore, it dissolve in aqueous NaOH.

32. Benzenesulphonyl chloride
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.5
3° amines
3° amine do not gives visible reaction with benzenesulphonyl chloride
Reaction with :
Acyl chloride
Summary of Hinsberg’s test:
Acid anhydride
1° amines  white precipitate  clear solution
NaOH
Benzenesulphonyl chloride
2° amines  white precipitate  do not dissolved
NaOH
Nitrous acid
Bromine water
3° amines  do not give any visible change
Formation of dye

33. Benzenesulphonyl chloride
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.5
Reaction with nitrous acid (NaNO2 + HCl)
Reaction with :
Nitrous acid (HNO2) is a weak and unstable acid.
Acyl chloride
It is always prepared in situ, by treating cold sodium nitrite (NaNO2) with an aqueous solution of a cold dilute hydrochloride acid (-5°C).
Acid anhydride
Benzenesulphonyl chloride
Nitrous acid
Nitrous acid reacts with all classes of
amines
Bromine water
Nitrous acid test can be used to distinguish:
1° aliphatic and 1° aromatic amines
1° and 2° aliphatic amines
Formation of dye

34. Benzenesulphonyl chloride
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.5
1° amines (Aliphatic)
Primary aliphatic amines react with nitrous acid to yield highly unstable aliphatic diazonium salts
Reaction with :
Acyl chloride
Acid anhydride
Benzenesulphonyl chloride
Nitrous acid
Bromine water
Observation :
Formation of gas bubbles (N2)
Formation of dye

35. Benzenesulphonyl chloride
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.5
1° amines (Aromatic)
Primary arylamines react with nitrous acid to give arenediazonium salts
Reaction with :
Acyl chloride
Acid anhydride
Benzenesulphonyl chloride
Nitrous acid
Bromine water
Formation of dye

36. 1° aliphatic amines and 2° aliphatic amines
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.5
1° aliphatic amines and 2° aliphatic amines
Reaction with :
Primary aliphatic amines
Form a mixture of alkenes, alcohols, alkyl halides and nitrogen gas.
Secondary aliphatic amines
Form secondary N-nitrosamines as yellow oil, which is stable under the reaction conditions.
Acyl chloride
Acid anhydride
Benzenesulphonyl chloride
Nitrous acid
Bromine water
Formation of dye

37. Benzenesulphonyl chloride
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
Identification test
19.5
Reaction with bromine water
Reaction with :
Aniline reacts with aqueous bromine to yield white precipitates
Acyl chloride
NH2 group is an activating and ortho-para directors group
Acid anhydride
Benzenesulphonyl chloride
Nitrous acid
Bromine water
(2,4,6-tribromoaniline)
Formation of dye
Observation: White precipitate formed

38. Benzenesulphonyl chloride
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.5
Formation of dye
Reaction with :
Primary arylamines react with nitrous acid to give arenediazonium salts which are stable at 0 C
Acyl chloride
Acid anhydride
Arenediazonium salts also undergo coupling reaction with aromatic compounds with strong electron donating group, such as –OH and –NR2 at the para position to yield azo compounds
Benzenesulphonyl chloride
Nitrous acid
Bromine water
Azo compounds are usually intensely coloured and relatively inexpensive compounds, they are used as dyes
Formation of dye

39. Benzenesulphonyl chloride
Chapter 19 : Amines
19.1 : Introduction
19.2 : Nomenclature
19.3 : Physical Properties
19.4 : Preparation
19.5 : Chemical properties
19.5
Reaction with :
Acyl chloride
Acid anhydride
Benzenesulphonyl chloride
Nitrous acid
Bromine water
Formation of dye