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Amines constitute an important class of organic
compounds derived by replacing one or more hydrogen
atoms of ammonia molecule by alkyl/aryl group(s). In
nature, they occur among proteins, vitamins, alkaloids
and hormones. Synthetic examples include polymers,
dye stuffs and drugs. Two biologically active
compounds, namely adrenaline and ephedrine, both
containing secondary amino group, are used to increase
blood pressure. Novocain, a synthetic amino compound,
is used as an anaesthetic in dentistry. Benadryl, a well
known antihistaminic drug also contains tertiary amino
group. Quaternary ammonium salts are used as
surfactants. Diazonium salts are intermediates in the
preparation of a  variety of aromatic compounds
including dyes. In this Unit, you will learn about amines
and diazonium salts.
I. AMINES
Amines can be considered as derivatives of ammonia,
obtained by replacement of one, two or all the three
hydrogen atoms by alkyl and/or aryl groups.
For example:
Like ammonia, nitrogen atom of amines is trivalent and
carries an unshared pair of electrons.  Nitrogen orbitals
in amines are therefore, sp
3
 hybridised and the geometry
of amines is pyramidal. Each of  the three sp
3
 hybridised
orbitals of nitrogen overlap with orbitals of hydrogen or
carbon depending upon the composition of the amines.
The fourth orbital of nitrogen in all amines contains an
unshared pair of electrons.  Due to the presence of
unshared pair of electrons, the angle C–N–E, (where E is
After studying this Unit, you will be
able to
• describe amines as derivatives of
ammonia having a pyramidal
structure;
• classify amines as primary,
secondary and tertiary;
• name amines by common names
and IUPAC system;
• describe some of the important
methods of preparation of amines;
• explain the properties of amines;
• distinguish between primary,
secondary and tertiary amines;
• describe the method of prepara-
tion of diazonium salts and their
importance in the synthesis of a
series of aromatic compounds
including azo dyes.
Objectives
“The chief commercial use of amines is as intermediates in the
synthesis of medicines and fibres” .
Unit Unit Unit Unit Unit
13
A A A A Amines mines mines mines mines
13
A A A A Amines mines mines mines mines
13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines
2022-23
Page 2


Amines constitute an important class of organic
compounds derived by replacing one or more hydrogen
atoms of ammonia molecule by alkyl/aryl group(s). In
nature, they occur among proteins, vitamins, alkaloids
and hormones. Synthetic examples include polymers,
dye stuffs and drugs. Two biologically active
compounds, namely adrenaline and ephedrine, both
containing secondary amino group, are used to increase
blood pressure. Novocain, a synthetic amino compound,
is used as an anaesthetic in dentistry. Benadryl, a well
known antihistaminic drug also contains tertiary amino
group. Quaternary ammonium salts are used as
surfactants. Diazonium salts are intermediates in the
preparation of a  variety of aromatic compounds
including dyes. In this Unit, you will learn about amines
and diazonium salts.
I. AMINES
Amines can be considered as derivatives of ammonia,
obtained by replacement of one, two or all the three
hydrogen atoms by alkyl and/or aryl groups.
For example:
Like ammonia, nitrogen atom of amines is trivalent and
carries an unshared pair of electrons.  Nitrogen orbitals
in amines are therefore, sp
3
 hybridised and the geometry
of amines is pyramidal. Each of  the three sp
3
 hybridised
orbitals of nitrogen overlap with orbitals of hydrogen or
carbon depending upon the composition of the amines.
The fourth orbital of nitrogen in all amines contains an
unshared pair of electrons.  Due to the presence of
unshared pair of electrons, the angle C–N–E, (where E is
After studying this Unit, you will be
able to
• describe amines as derivatives of
ammonia having a pyramidal
structure;
• classify amines as primary,
secondary and tertiary;
• name amines by common names
and IUPAC system;
• describe some of the important
methods of preparation of amines;
• explain the properties of amines;
• distinguish between primary,
secondary and tertiary amines;
• describe the method of prepara-
tion of diazonium salts and their
importance in the synthesis of a
series of aromatic compounds
including azo dyes.
Objectives
“The chief commercial use of amines is as intermediates in the
synthesis of medicines and fibres” .
Unit Unit Unit Unit Unit
13
A A A A Amines mines mines mines mines
13
A A A A Amines mines mines mines mines
13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines
2022-23
390 Chemistry
C or H) is less than 109.5°; for instance, it is 108
o
 in case of
trimethylamine as shown in Fig. 13.1.
Amines are classified as primary (1
o
), secondary (2
o
) and tertiary (3
o
)
depending upon the number of hydrogen atoms replaced by alkyl or
aryl groups in ammonia molecule.  If one hydrogen atom of ammonia
is replaced by R or Ar , we get RNH
2 
or ArNH
2
, a primary amine (1
o
).
If two hydrogen atoms of ammonia or one hydrogen atom of R-NH
2
 are
replaced by another alkyl/aryl(R’) group,  what would you get? You
get R-NHR’, secondary amine.  The second alkyl/aryl group may be
same or different. Replacement of another hydrogen atom by alkyl/aryl
group leads to the formation of tertiary amine. Amines are said to be
‘simple’ when all the alkyl or aryl groups are the same, and ‘mixed’
when they are different.
In common system, an aliphatic amine is named by prefixing alkyl
group to amine, i.e., alkylamine as one word (e.g., methylamine).  In
secondary and tertiary amines, when two or more groups are the same,
the prefix di or tri is appended before the name of alkyl group.  In
IUPAC system, primary amines are named as alkanamines. The name
is derived by replacement of ‘e’ of alkane by the word amine. For
example, CH
3
NH
2
 is named as methanamine. In case, more than one
amino group is present at different positions in the parent chain, their
positions are specified by giving numbers to the carbon atoms bearing
–NH
2
 groups and suitable prefix such as di, tri, etc. is attached to the
amine. The letter ‘e’ of the suffix of the hydrocarbon part is retained. For
example, H
2
N–CH
2
–CH
2
–NH
2
 is named as ethane-1, 2-diamine.
To name secondary and tertiary amines, we use locant N to designate
substituent attached to a nitrogen atom. For example, CH
3
 NHCH
2
CH
3
 is
13.2 13.2 13.2 13.2 13.2 Classification Classification Classification Classification Classification
Fig. 13.1 Pyramidal shape of trimethylamine
13.3 13.3 13.3 13.3 13.3 Nomenclature Nomenclature Nomenclature Nomenclature Nomenclature
2022-23
Page 3


Amines constitute an important class of organic
compounds derived by replacing one or more hydrogen
atoms of ammonia molecule by alkyl/aryl group(s). In
nature, they occur among proteins, vitamins, alkaloids
and hormones. Synthetic examples include polymers,
dye stuffs and drugs. Two biologically active
compounds, namely adrenaline and ephedrine, both
containing secondary amino group, are used to increase
blood pressure. Novocain, a synthetic amino compound,
is used as an anaesthetic in dentistry. Benadryl, a well
known antihistaminic drug also contains tertiary amino
group. Quaternary ammonium salts are used as
surfactants. Diazonium salts are intermediates in the
preparation of a  variety of aromatic compounds
including dyes. In this Unit, you will learn about amines
and diazonium salts.
I. AMINES
Amines can be considered as derivatives of ammonia,
obtained by replacement of one, two or all the three
hydrogen atoms by alkyl and/or aryl groups.
For example:
Like ammonia, nitrogen atom of amines is trivalent and
carries an unshared pair of electrons.  Nitrogen orbitals
in amines are therefore, sp
3
 hybridised and the geometry
of amines is pyramidal. Each of  the three sp
3
 hybridised
orbitals of nitrogen overlap with orbitals of hydrogen or
carbon depending upon the composition of the amines.
The fourth orbital of nitrogen in all amines contains an
unshared pair of electrons.  Due to the presence of
unshared pair of electrons, the angle C–N–E, (where E is
After studying this Unit, you will be
able to
• describe amines as derivatives of
ammonia having a pyramidal
structure;
• classify amines as primary,
secondary and tertiary;
• name amines by common names
and IUPAC system;
• describe some of the important
methods of preparation of amines;
• explain the properties of amines;
• distinguish between primary,
secondary and tertiary amines;
• describe the method of prepara-
tion of diazonium salts and their
importance in the synthesis of a
series of aromatic compounds
including azo dyes.
Objectives
“The chief commercial use of amines is as intermediates in the
synthesis of medicines and fibres” .
Unit Unit Unit Unit Unit
13
A A A A Amines mines mines mines mines
13
A A A A Amines mines mines mines mines
13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines
2022-23
390 Chemistry
C or H) is less than 109.5°; for instance, it is 108
o
 in case of
trimethylamine as shown in Fig. 13.1.
Amines are classified as primary (1
o
), secondary (2
o
) and tertiary (3
o
)
depending upon the number of hydrogen atoms replaced by alkyl or
aryl groups in ammonia molecule.  If one hydrogen atom of ammonia
is replaced by R or Ar , we get RNH
2 
or ArNH
2
, a primary amine (1
o
).
If two hydrogen atoms of ammonia or one hydrogen atom of R-NH
2
 are
replaced by another alkyl/aryl(R’) group,  what would you get? You
get R-NHR’, secondary amine.  The second alkyl/aryl group may be
same or different. Replacement of another hydrogen atom by alkyl/aryl
group leads to the formation of tertiary amine. Amines are said to be
‘simple’ when all the alkyl or aryl groups are the same, and ‘mixed’
when they are different.
In common system, an aliphatic amine is named by prefixing alkyl
group to amine, i.e., alkylamine as one word (e.g., methylamine).  In
secondary and tertiary amines, when two or more groups are the same,
the prefix di or tri is appended before the name of alkyl group.  In
IUPAC system, primary amines are named as alkanamines. The name
is derived by replacement of ‘e’ of alkane by the word amine. For
example, CH
3
NH
2
 is named as methanamine. In case, more than one
amino group is present at different positions in the parent chain, their
positions are specified by giving numbers to the carbon atoms bearing
–NH
2
 groups and suitable prefix such as di, tri, etc. is attached to the
amine. The letter ‘e’ of the suffix of the hydrocarbon part is retained. For
example, H
2
N–CH
2
–CH
2
–NH
2
 is named as ethane-1, 2-diamine.
To name secondary and tertiary amines, we use locant N to designate
substituent attached to a nitrogen atom. For example, CH
3
 NHCH
2
CH
3
 is
13.2 13.2 13.2 13.2 13.2 Classification Classification Classification Classification Classification
Fig. 13.1 Pyramidal shape of trimethylamine
13.3 13.3 13.3 13.3 13.3 Nomenclature Nomenclature Nomenclature Nomenclature Nomenclature
2022-23
391 Amines
named as N-methylethanamine and (CH
3
CH
2
)
3
N is named as N, N-
diethylethanamine. More examples are given in Table 13.1.
In arylamines, –NH
2
 group is directly attached to the benzene ring.
C
6
H
5
NH
2
 is the simplest example of arylamine.  In common system, it
is known as aniline. It is also an accepted IUPAC name. While naming
arylamines according to IUPAC system, suffix ‘e’ of arene is replaced by
‘amine’. Thus in IUPAC system, C
6
H
5
–NH
2
 is named as benzenamine.
Common and IUPAC names of some alkylamines and arylamines are
given in Table 13.1.
Amine Common name IUPAC name
CH
3-
–CH
2
–NH
2
Ethylamine Ethanamine
CH
3
–CH
2
–CH
2
–NH
2
n-Propylamine Propan-1-amine
Isopropylamine Propan-2-amine
Ethylmethylamine N-Methylethanamine
Trimethylamine N,N-Dimethylmethanamine
N,N-Diethylbutylamine N,N-Diethylbutan-1-amine
Allylamine Prop-2-en-1-amine
Hexamethylenediamine Hexane-1,6-diamine
Aniline Aniline or Benzenamine
o-Toluidine 2-Methylaniline
p-Bromoaniline 4-Bromobenzenamine
or
4-Bromoaniline
N,N-Dimethylaniline N,N-Dimethylbenzenamine
Table 13.1: Nomenclature of Some Alkylamines and Arylamines
2022-23
Page 4


Amines constitute an important class of organic
compounds derived by replacing one or more hydrogen
atoms of ammonia molecule by alkyl/aryl group(s). In
nature, they occur among proteins, vitamins, alkaloids
and hormones. Synthetic examples include polymers,
dye stuffs and drugs. Two biologically active
compounds, namely adrenaline and ephedrine, both
containing secondary amino group, are used to increase
blood pressure. Novocain, a synthetic amino compound,
is used as an anaesthetic in dentistry. Benadryl, a well
known antihistaminic drug also contains tertiary amino
group. Quaternary ammonium salts are used as
surfactants. Diazonium salts are intermediates in the
preparation of a  variety of aromatic compounds
including dyes. In this Unit, you will learn about amines
and diazonium salts.
I. AMINES
Amines can be considered as derivatives of ammonia,
obtained by replacement of one, two or all the three
hydrogen atoms by alkyl and/or aryl groups.
For example:
Like ammonia, nitrogen atom of amines is trivalent and
carries an unshared pair of electrons.  Nitrogen orbitals
in amines are therefore, sp
3
 hybridised and the geometry
of amines is pyramidal. Each of  the three sp
3
 hybridised
orbitals of nitrogen overlap with orbitals of hydrogen or
carbon depending upon the composition of the amines.
The fourth orbital of nitrogen in all amines contains an
unshared pair of electrons.  Due to the presence of
unshared pair of electrons, the angle C–N–E, (where E is
After studying this Unit, you will be
able to
• describe amines as derivatives of
ammonia having a pyramidal
structure;
• classify amines as primary,
secondary and tertiary;
• name amines by common names
and IUPAC system;
• describe some of the important
methods of preparation of amines;
• explain the properties of amines;
• distinguish between primary,
secondary and tertiary amines;
• describe the method of prepara-
tion of diazonium salts and their
importance in the synthesis of a
series of aromatic compounds
including azo dyes.
Objectives
“The chief commercial use of amines is as intermediates in the
synthesis of medicines and fibres” .
Unit Unit Unit Unit Unit
13
A A A A Amines mines mines mines mines
13
A A A A Amines mines mines mines mines
13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines
2022-23
390 Chemistry
C or H) is less than 109.5°; for instance, it is 108
o
 in case of
trimethylamine as shown in Fig. 13.1.
Amines are classified as primary (1
o
), secondary (2
o
) and tertiary (3
o
)
depending upon the number of hydrogen atoms replaced by alkyl or
aryl groups in ammonia molecule.  If one hydrogen atom of ammonia
is replaced by R or Ar , we get RNH
2 
or ArNH
2
, a primary amine (1
o
).
If two hydrogen atoms of ammonia or one hydrogen atom of R-NH
2
 are
replaced by another alkyl/aryl(R’) group,  what would you get? You
get R-NHR’, secondary amine.  The second alkyl/aryl group may be
same or different. Replacement of another hydrogen atom by alkyl/aryl
group leads to the formation of tertiary amine. Amines are said to be
‘simple’ when all the alkyl or aryl groups are the same, and ‘mixed’
when they are different.
In common system, an aliphatic amine is named by prefixing alkyl
group to amine, i.e., alkylamine as one word (e.g., methylamine).  In
secondary and tertiary amines, when two or more groups are the same,
the prefix di or tri is appended before the name of alkyl group.  In
IUPAC system, primary amines are named as alkanamines. The name
is derived by replacement of ‘e’ of alkane by the word amine. For
example, CH
3
NH
2
 is named as methanamine. In case, more than one
amino group is present at different positions in the parent chain, their
positions are specified by giving numbers to the carbon atoms bearing
–NH
2
 groups and suitable prefix such as di, tri, etc. is attached to the
amine. The letter ‘e’ of the suffix of the hydrocarbon part is retained. For
example, H
2
N–CH
2
–CH
2
–NH
2
 is named as ethane-1, 2-diamine.
To name secondary and tertiary amines, we use locant N to designate
substituent attached to a nitrogen atom. For example, CH
3
 NHCH
2
CH
3
 is
13.2 13.2 13.2 13.2 13.2 Classification Classification Classification Classification Classification
Fig. 13.1 Pyramidal shape of trimethylamine
13.3 13.3 13.3 13.3 13.3 Nomenclature Nomenclature Nomenclature Nomenclature Nomenclature
2022-23
391 Amines
named as N-methylethanamine and (CH
3
CH
2
)
3
N is named as N, N-
diethylethanamine. More examples are given in Table 13.1.
In arylamines, –NH
2
 group is directly attached to the benzene ring.
C
6
H
5
NH
2
 is the simplest example of arylamine.  In common system, it
is known as aniline. It is also an accepted IUPAC name. While naming
arylamines according to IUPAC system, suffix ‘e’ of arene is replaced by
‘amine’. Thus in IUPAC system, C
6
H
5
–NH
2
 is named as benzenamine.
Common and IUPAC names of some alkylamines and arylamines are
given in Table 13.1.
Amine Common name IUPAC name
CH
3-
–CH
2
–NH
2
Ethylamine Ethanamine
CH
3
–CH
2
–CH
2
–NH
2
n-Propylamine Propan-1-amine
Isopropylamine Propan-2-amine
Ethylmethylamine N-Methylethanamine
Trimethylamine N,N-Dimethylmethanamine
N,N-Diethylbutylamine N,N-Diethylbutan-1-amine
Allylamine Prop-2-en-1-amine
Hexamethylenediamine Hexane-1,6-diamine
Aniline Aniline or Benzenamine
o-Toluidine 2-Methylaniline
p-Bromoaniline 4-Bromobenzenamine
or
4-Bromoaniline
N,N-Dimethylaniline N,N-Dimethylbenzenamine
Table 13.1: Nomenclature of Some Alkylamines and Arylamines
2022-23
392 Chemistry
Amines are prepared by the following methods:
1. Reduction of nitro compounds
Nitro compounds are reduced to amines by passing hydrogen gas
in the presence of finely divided nickel, palladium or platinum and
also by reduction with metals in acidic medium. Nitroalkanes can
also be similarly reduced to the corresponding alkanamines.
Reduction with iron scrap and hydrochloric acid is preferred because
FeCl
2
 formed gets hydrolysed to release hydrochloric acid during the
reaction. Thus, only a small amount of hydrochloric acid is required
to initiate the reaction.
2. Ammonolysis of alkyl halides
You have read (Unit 10, Class XII) that the carbon - halogen bond
in alkyl or benzyl halides can be easily cleaved by a nucleophile.
Hence, an alkyl or benzyl halide on reaction with an ethanolic
solution of ammonia undergoes nucleophilic substitution reaction
in which the halogen atom is replaced by an amino (–NH
2
) group.
This process of cleavage of the C–X bond by ammonia molecule is
known as ammonolysis.  The reaction is carried out in a sealed
tube at 373 K.  The primary amine thus obtained behaves as a
nucleophile and can further react with alkyl halide to form secondary
and tertiary amines, and finally quaternary ammonium salt.
13.4 13.4 13.4 13.4 13.4 Preparation Preparation Preparation Preparation Preparation
of Amines of Amines of Amines of Amines of Amines
13.1 Classify the following amines as primary, secondary or tertiary:
13.2 (i) Write structures of different isomeric amines corresponding to the molecular
formula, C
4
H
11
N.
(ii) Write IUPAC names of all the isomers.
(iii) What type of isomerism is exhibited by different pairs of amines?
Intext Questions Intext Questions Intext Questions Intext Questions Intext Questions
2022-23
Page 5


Amines constitute an important class of organic
compounds derived by replacing one or more hydrogen
atoms of ammonia molecule by alkyl/aryl group(s). In
nature, they occur among proteins, vitamins, alkaloids
and hormones. Synthetic examples include polymers,
dye stuffs and drugs. Two biologically active
compounds, namely adrenaline and ephedrine, both
containing secondary amino group, are used to increase
blood pressure. Novocain, a synthetic amino compound,
is used as an anaesthetic in dentistry. Benadryl, a well
known antihistaminic drug also contains tertiary amino
group. Quaternary ammonium salts are used as
surfactants. Diazonium salts are intermediates in the
preparation of a  variety of aromatic compounds
including dyes. In this Unit, you will learn about amines
and diazonium salts.
I. AMINES
Amines can be considered as derivatives of ammonia,
obtained by replacement of one, two or all the three
hydrogen atoms by alkyl and/or aryl groups.
For example:
Like ammonia, nitrogen atom of amines is trivalent and
carries an unshared pair of electrons.  Nitrogen orbitals
in amines are therefore, sp
3
 hybridised and the geometry
of amines is pyramidal. Each of  the three sp
3
 hybridised
orbitals of nitrogen overlap with orbitals of hydrogen or
carbon depending upon the composition of the amines.
The fourth orbital of nitrogen in all amines contains an
unshared pair of electrons.  Due to the presence of
unshared pair of electrons, the angle C–N–E, (where E is
After studying this Unit, you will be
able to
• describe amines as derivatives of
ammonia having a pyramidal
structure;
• classify amines as primary,
secondary and tertiary;
• name amines by common names
and IUPAC system;
• describe some of the important
methods of preparation of amines;
• explain the properties of amines;
• distinguish between primary,
secondary and tertiary amines;
• describe the method of prepara-
tion of diazonium salts and their
importance in the synthesis of a
series of aromatic compounds
including azo dyes.
Objectives
“The chief commercial use of amines is as intermediates in the
synthesis of medicines and fibres” .
Unit Unit Unit Unit Unit
13
A A A A Amines mines mines mines mines
13
A A A A Amines mines mines mines mines
13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines 13.1 Structure of Amines
2022-23
390 Chemistry
C or H) is less than 109.5°; for instance, it is 108
o
 in case of
trimethylamine as shown in Fig. 13.1.
Amines are classified as primary (1
o
), secondary (2
o
) and tertiary (3
o
)
depending upon the number of hydrogen atoms replaced by alkyl or
aryl groups in ammonia molecule.  If one hydrogen atom of ammonia
is replaced by R or Ar , we get RNH
2 
or ArNH
2
, a primary amine (1
o
).
If two hydrogen atoms of ammonia or one hydrogen atom of R-NH
2
 are
replaced by another alkyl/aryl(R’) group,  what would you get? You
get R-NHR’, secondary amine.  The second alkyl/aryl group may be
same or different. Replacement of another hydrogen atom by alkyl/aryl
group leads to the formation of tertiary amine. Amines are said to be
‘simple’ when all the alkyl or aryl groups are the same, and ‘mixed’
when they are different.
In common system, an aliphatic amine is named by prefixing alkyl
group to amine, i.e., alkylamine as one word (e.g., methylamine).  In
secondary and tertiary amines, when two or more groups are the same,
the prefix di or tri is appended before the name of alkyl group.  In
IUPAC system, primary amines are named as alkanamines. The name
is derived by replacement of ‘e’ of alkane by the word amine. For
example, CH
3
NH
2
 is named as methanamine. In case, more than one
amino group is present at different positions in the parent chain, their
positions are specified by giving numbers to the carbon atoms bearing
–NH
2
 groups and suitable prefix such as di, tri, etc. is attached to the
amine. The letter ‘e’ of the suffix of the hydrocarbon part is retained. For
example, H
2
N–CH
2
–CH
2
–NH
2
 is named as ethane-1, 2-diamine.
To name secondary and tertiary amines, we use locant N to designate
substituent attached to a nitrogen atom. For example, CH
3
 NHCH
2
CH
3
 is
13.2 13.2 13.2 13.2 13.2 Classification Classification Classification Classification Classification
Fig. 13.1 Pyramidal shape of trimethylamine
13.3 13.3 13.3 13.3 13.3 Nomenclature Nomenclature Nomenclature Nomenclature Nomenclature
2022-23
391 Amines
named as N-methylethanamine and (CH
3
CH
2
)
3
N is named as N, N-
diethylethanamine. More examples are given in Table 13.1.
In arylamines, –NH
2
 group is directly attached to the benzene ring.
C
6
H
5
NH
2
 is the simplest example of arylamine.  In common system, it
is known as aniline. It is also an accepted IUPAC name. While naming
arylamines according to IUPAC system, suffix ‘e’ of arene is replaced by
‘amine’. Thus in IUPAC system, C
6
H
5
–NH
2
 is named as benzenamine.
Common and IUPAC names of some alkylamines and arylamines are
given in Table 13.1.
Amine Common name IUPAC name
CH
3-
–CH
2
–NH
2
Ethylamine Ethanamine
CH
3
–CH
2
–CH
2
–NH
2
n-Propylamine Propan-1-amine
Isopropylamine Propan-2-amine
Ethylmethylamine N-Methylethanamine
Trimethylamine N,N-Dimethylmethanamine
N,N-Diethylbutylamine N,N-Diethylbutan-1-amine
Allylamine Prop-2-en-1-amine
Hexamethylenediamine Hexane-1,6-diamine
Aniline Aniline or Benzenamine
o-Toluidine 2-Methylaniline
p-Bromoaniline 4-Bromobenzenamine
or
4-Bromoaniline
N,N-Dimethylaniline N,N-Dimethylbenzenamine
Table 13.1: Nomenclature of Some Alkylamines and Arylamines
2022-23
392 Chemistry
Amines are prepared by the following methods:
1. Reduction of nitro compounds
Nitro compounds are reduced to amines by passing hydrogen gas
in the presence of finely divided nickel, palladium or platinum and
also by reduction with metals in acidic medium. Nitroalkanes can
also be similarly reduced to the corresponding alkanamines.
Reduction with iron scrap and hydrochloric acid is preferred because
FeCl
2
 formed gets hydrolysed to release hydrochloric acid during the
reaction. Thus, only a small amount of hydrochloric acid is required
to initiate the reaction.
2. Ammonolysis of alkyl halides
You have read (Unit 10, Class XII) that the carbon - halogen bond
in alkyl or benzyl halides can be easily cleaved by a nucleophile.
Hence, an alkyl or benzyl halide on reaction with an ethanolic
solution of ammonia undergoes nucleophilic substitution reaction
in which the halogen atom is replaced by an amino (–NH
2
) group.
This process of cleavage of the C–X bond by ammonia molecule is
known as ammonolysis.  The reaction is carried out in a sealed
tube at 373 K.  The primary amine thus obtained behaves as a
nucleophile and can further react with alkyl halide to form secondary
and tertiary amines, and finally quaternary ammonium salt.
13.4 13.4 13.4 13.4 13.4 Preparation Preparation Preparation Preparation Preparation
of Amines of Amines of Amines of Amines of Amines
13.1 Classify the following amines as primary, secondary or tertiary:
13.2 (i) Write structures of different isomeric amines corresponding to the molecular
formula, C
4
H
11
N.
(ii) Write IUPAC names of all the isomers.
(iii) What type of isomerism is exhibited by different pairs of amines?
Intext Questions Intext Questions Intext Questions Intext Questions Intext Questions
2022-23
393 Amines
The free amine can be obtained from the ammonium salt by treatment
with a strong base:
Ammonolysis has the disadvantage of yielding a mixture of primary,
secondary and tertiary amines and also a quaternary ammonium salt.
However, primary amine is obtained as a major product by taking
large excess of ammonia.
The order of reactivity of halides with amines is RI > RBr >RCl.
3. Reduction of nitriles
Nitriles on reduction with lithium aluminium hydride (LiAlH
4
) or
catalytic hydrogenation produce primary amines. This reaction is
used for ascent of amine series, i.e., for preparation of amines
containing one carbon atom more than the starting amine.
4. Reduction of amides
The amides on reduction with lithium aluminium hydride yield
amines.
Example 13.1 Example 13.1 Example 13.1 Example 13.1 Example 13.1
Solution Solution Solution Solution Solution
Write chemical equations for the following reactions:
(i) Reaction of ethanolic NH
3
 with C
2
H
5
Cl.
(ii) Ammonolysis of benzyl chloride and reaction of amine so formed
with two moles of CH
3
Cl.
2022-23
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FAQs on NCERT Textbook: Amines - Chemistry Class 12 - NEET

1. What are amines and what are their properties?
Ans. Amines are organic compounds that contain a nitrogen atom bonded to carbon atoms. They are derived from ammonia (NH3) by replacing one or more hydrogen atoms with alkyl or aryl groups. Amines can be classified as primary, secondary, or tertiary based on the number of carbon groups attached to the nitrogen atom. They have a characteristic ammonia-like odor and can be either a liquid or a solid at room temperature. Amines are generally polar and can form hydrogen bonds, which affects their boiling points and solubility in water.
2. How are amines prepared?
Ans. Amines can be prepared through various methods. Some common methods include: - Alkylation: Primary amines can be prepared by reacting ammonia with alkyl halides or primary alkyl halides. - Reduction of Nitro Compounds: Amines can be synthesized by reducing nitro compounds using reducing agents such as hydrogen gas and metal catalysts. - Gabriel Synthesis: Primary amines can be prepared by reacting phthalimide with alkyl halides followed by hydrolysis. - Hofmann Rearrangement: Primary amines can be obtained by treating primary amides with bromine and sodium hydroxide.
3. What are the uses of amines?
Ans. Amines have various applications in different fields. Some common uses of amines include: - Pharmaceuticals: Amines are used in the synthesis of many drugs and medications. They can act as bases, form salts, and participate in various chemical reactions. - Agriculture: Amines are used as intermediates in the production of pesticides, herbicides, and fungicides. They help in controlling pests, weeds, and diseases in crops. - Dyes and Pigments: Amines are used in the production of dyes and pigments. They can act as chromophores and provide color to various materials. - Rubber Industry: Amines are used as accelerators in the vulcanization process of rubber. They help in improving the elasticity, strength, and durability of rubber products. - Corrosion Inhibitors: Amines are used as corrosion inhibitors to protect metals from rusting and degradation in various industrial processes.
4. What are the harmful effects of amines?
Ans. While amines have several beneficial uses, they can also have harmful effects on human health and the environment. Some of the harmful effects of amines include: - Irritation: Amines can cause irritation to the skin, eyes, and respiratory system upon direct contact or inhalation. - Toxicity: Certain amines, such as aromatic amines, can be toxic and carcinogenic. Prolonged exposure to these substances can lead to serious health issues, including cancer. - Environmental Impact: Amines can be released into the environment through industrial processes and waste disposal. They can contribute to water pollution and harm aquatic organisms. - Allergic Reactions: Some individuals may develop allergic reactions to amines, leading to symptoms such as rashes, itching, and difficulty breathing.
5. How do amines act as bases?
Ans. Amines act as bases due to the presence of a lone pair of electrons on the nitrogen atom. This lone pair can accept a proton (H+) from an acid, forming a new bond and creating a positively charged ammonium ion. The basicity of amines depends on factors such as the electron-donating ability of the substituents attached to the nitrogen atom and the steric hindrance present. Primary amines are generally more basic than secondary and tertiary amines. The basic nature of amines allows them to react with acids, neutralizing them and forming salts.
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