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AMINES, DIAZONIUM SALTS, CYANIDES & ISOCYANIDES
AMINES, DIAZONIUM SALTS,
CYANIDES & ISOCYANIDES

STRUCTURE OF AMINES

ORGANIC COMPOUNDS CONTAINING NITROGEN
DIAZONIUM SALTS
ALKYL CYANIDES
ALKYL ISOCYANIDES
AMINES

AMINES
Amines are derivatives of ammonia, obtained by replacement of one, two
or all the three hydrogen atoms by alkyl or aryl groups.
Eg:
 N 

C
C
C

AMINES Structure of amines
 Nitrogen orbitals in amines are sp3
hybridised and the geometry of
amines is pyramidal.
 Each of the three sp3
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.

AMINES Structure of amines
Unshared
Electron pair
CH3
CH3
CH3
:
1080

1) Amines are derivatives of…
a) Ammonia
b) Oxygen
c) Water
d) Hydrogen sulphide
MCQS

2) In amines nitrogen atom undergoes ____ hybridization…
a) sp3
b) sp2
c) sp
d) sp3
d

3) No. of lone pairs on nitrogen atom in amine are …
a) 2
b) 3
c) 1
d) 4

CLASSIFICATION &
NOMENCLATURE OF AMINES

AMINES Classification
 On the basis of the number of alkyl groups attached to nitrogen
amines are classified as
1º (primary amine) RNH2
2º (secondary amine) R2NH
3º (tertiary amine) R3N

 In common system, an aliphatic amine is named by prefixing alkyl group
to amine.
 In secondary and tertiary amines when two (or) more groups are same,
the prefix di (or) tri is appended before the name of alkyl group.
 In IUPAC system, amines are named as alkanamine derived by
replacement of ‘e’ of alkane by the word amine.

Alk + an + amine = alkanamine
 If different alkyl groups are attached to N- the longest chain becomes
parent alkyl and remaining alkyl groups added as prefixes in alphabetical
order.

AMINES Nomenclature
Amine
Common Name
I.U.P.A.C. Name
CH3  CH2  NH2
Ethylamine
Ethanamine

AMINES Nomenclature
Amine
Common Name
I.U.P.A.C. Name
CH3  CH2  CH2 NH2
n-Propylamine
Propan -1- amine

AMINES Nomenclature
Amine
Common Name
I.U.P.A.C. Name
Isopropylamine
Propan -2- amine
CH3  CH2  CH2

NH2

AMINES Nomenclature
Amine
Common Name
I.U.P.A.C. Name
Ethyl methylamine
N-Methyl ethanamine
CH3  N  CH2  CH3

H

AMINES Nomenclature
Amine
Common Name
I.U.P.A.C. Name
Trimethylamine
N,N- Dimethylmethan
amine
CH3  N  CH3

CH3

AMINES Nomenclature
Amine
Common Name
I.U.P.A.C. Name
N,N- Diethylbutylamine
N,N- Diethylbutan-1-amine
C2H5NCH2CH2CH3 CH3

C2H5
1 2 3 4

AMINES Nomenclature
Amine
Common Name
I.U.P.A.C. Name
Allylamine
Prop-2-en-1-amine
NH2  CH2  CH = CH2
1 2 3

AMINES Nomenclature
Amine
Common Name
I.U.P.A.C. Name
Hexamethylenediamine
Hexan-1,6-
diamine
NH2  (CH2)6  NH2

NH2
NH2
CH3
Aniline Aniline or Benzamine
O - Toluidine 2- Aminotoluene
NH2
Br
N
p- Bromo
aniline
N,N – Dimethyl
aniline
4- Bromobenzamine
or
4- Bromoaniline
N,N – Dimethylbenzenamine

1) Classify the following amines as primary, secondary or tertiary :
i) primary;
NH2
(i)
N(CH3)2
(ii)
(iii) (C2H5)2CHNH2 (iv) (C2H5)2NH
ii) tertiary;
iii) primary;
iv) secondary.
Answer

2) (i) Write the structure of different isomeric amines corresponding to
the molecular formula, C4H11N;
(i) and (ii) Eight isomers of C4H11N are
(ii) Write IUPAC names of all the isomers;
(iii) What type of isomerism is exhibited by different pairs of amines ?
(a) CH3 - CH2 – CH2 – CH2 – NH2
(b) CH3 - CH – CH2 – NH2
CH3
Butan–1-amine
(primary)
2 – methylpropan – 1 - amine
(primary)

(c) CH3 – CH2 – CH – (d) CH3 – C – NH2
CH3
CH3
Butan– 2 - amine
(primary)
2-methylpropan-2-amine
(primary)
(e) C2H5 – N – H
C2H5
N-ethylethanamine
(secondary)
(f) C3H7 – N – H
CH3
N-methylpropan-1-amine
(secondary)
NH2
CH3

(g) CH3 – CH – NH – CH3
CH3
(h) CH3 – N – CH3
C2H5
N-methylpropan-2-amine
(secondary)
N,N-dimethylethanamine
(tertiary)

(a)&(c ), (b)&(d), (f)&(g)
(a)&(e) , (a)&(f), (a)&(g), (a)&(h), (b)&(e), (b)&(f),
(b)&(g),(b)&(h), (c)&(e), (c)&(f), (c)&(g), (c)&(h), (d)&(e) ,
(d)&(f), (d)&(g), (d)&(h), (e)&(h), (f)&(h), (g)&(h)
(e)&(f), (e)&(g)
 Positional isomers
 Functional group isomers
 Metamers
 Chain isomers
(a)&(b), (a)&(d), (b) &(c), (c) &
(d)
(iii) What type of isomerism is exhibited by different pairs of amines ?

1) The structural formula of N-methyl amino methane is…
a) (CH3)2CHNH2
b) (CH3)3N
c) (CH3)2NH
d) CH3NH2
MCQS

2) IUPAC name of CH3 (CH2)2NH2 is…
a) 1- Propanamine
b) 2-methyl ethanamine
c) Iso-Propylamine
d) Methyl amine

3) Which of the following is a 10
amine?
a) (CH3)3 CNH2
b) C6H5NHCH3
c) CH3NHCH(CH3)2
d) (CH3CH2)2NCH3

4) Which of the following is a secondary amine?
a) H2N-NH2
b) CH3-NH2
c) (CH3)2NC6H5
d) C6H5-NH-CH3

PREPARATION OF AMINES

Preparation of Amines
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.
NO2 H2/Pd
Ethanol
NH2
NO2 Sn+HCl
or Fe+HCl
NH2

2) Ammonolysis of alkyl halides:
This reaction is carried out in a sealed tube at 373 K.
The process of cleavage of the
C–X bond by ammonia molecule
is known as Ammonolysis.
NH3
. .
+ R  X R  NH3 X
+ 
Nucleophile
Substituted ammonium salt

(10
) (20
) (30
) Quaternary ammonium salt
RNH2 R2NH R3N R4NX
RX RX RX + 
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 excess
of ammonia.

By treatment of the ammonium salt with a strong base, free amine is
obtained.
The order of reactivity of halides with amines is
.
RNH3X + NaOH RNH2 +H2O + NaX
+  
+
2) Ammonolysis of alkyl halides:

3) Reduction of nitriles:
 Nitriles on reduction with lithium aluminium hydride () or catalytic
hydrogenation produce primary amines.
R  C  N
Na/C2H5OH
H2/Ni
Nitrile is a cyanide group
R  CH2  NH2

4) Reduction of amides:
 The amides on reduction with lithium aluminium hydride yield
amines.
=

R  C
O
NH2
=

R  C
O
NH2
(i) LiAlH4
(ii) H2O
R  CH2 NH2
Amide is

5) Gabriel phthalimide synthesis:
 This synthesis is used for the preparation of only primary amines.
C
=
O
C
=
O
N  H
KOH C
=
O
C
=
O
NK
- +
C
=
O
C
=
O
N  R
NaOH(aq)
+
+
-
- + R  NH2
Phthalimide
( 10
amine )
R-X
C
=
O
C
=
O
ONa
ONa
-H2O -KX

Gabriel phthalimide synthesis exclusively
forms primary amines only, why?
Phthalimide on treatment with ethanolic KOH forms potassium salt of
phthalimide which on heating with alkyl halide followed by hydrolysis gives
primary amine (Breakage of two amide bonds takes place).

Aromatic primary amines cannot be
prepared by Gabriel phthalimide
synthesis, Why?

C
=
O
C
=
O
NK + C6H5-X
Heat
No reaction
Potassium phthalimide
In Gabriel phthalimide reaction, potassium salt of
phthalimide is formed. It reacts readily with alkyl halide
to form the corresponding alkyl derivative. But aryl
halide does not react with potassium phthalimide.
Because C-X bond in halo arene is difficult to be cleaved
due to partial double bond character. So, aromatic
primary amines cannot be prepared by this method.

 Primary amines can be prepared by treating an amide with
bromine in an aqueous or ethanolic solution of sodium hydroxide.
6) Hoffmann bromamide degradation reaction:
=

R  C
O
NH2 Br2 + 4NaOH
R – NH2 + Na2CO3 + 2NaBr+ 2H2O
+
( 10
amine )

3) How will you convert...
(i) benzene to aniline ?
(ii) Benzene to N, N-dimethyl aniline ?
(iii) Cl – (CH2)4 - Cl to hexan-1, 6-diamine ?

(i) Benzene to aniline
Con H2SO4+
Con HNO3, <600
C Sn/HCl
Benzene
NO2
6
NH2
Aniline

(ii) Benzene to N, N – dimethyl aniline
(i) HNO3+H2SO4 ,<600
C
(2 mole)
(CH3Cl )
N(CH3)2
Benzene
NO2
N,N-dimethyl aniline
NH2
Aniline
(ii) Sn/HCl

(iii) Cl – (CH2)4 – Cl to hexan -1,6 - diamine
Cl – (CH2)4 – Cl + 2KCN
Alcohol
-2KCl
H2/Pt
or LiAlH4
Hexan-1, 6-diamine
NH2CH2(CH2)4CH2NH2
NC-(CH2)4 – CN

1)
a) b)
c) d)
MCQS
A.The compound ‘A’ is…
NO2
H2/pd
C2H5OH
OH NH2
CONH2
NH2

2) In the reaction of C6H5OH
a) C6H5NH2
b) C6H5Cl
c) C6H5OH
d) C6H5COOH
NH3
ZnCl2
X; ‘X’ may be

3) Nitro benzene on reduction with Sn/HCl gives ‘A’ which on reaction
with acetyl chloride forms ‘B’ which of the following is ‘B’?
a) C6H5 - CO – CH3
b) C6H5 – NH - CO –CH3
c) C6H5 – NH3Cl
d) C6H5 – O – CO – CH3
–
+

4) Gabriel phthalimide synthesis is used for the preparation of …
a) 10
amine
b) 20
amine
c) 30
amine
d) 40
amine

CONVERSIONS AND
PHYSICAL PROPERTIES

Write Chemical equations for the following reaction :
(i)Reaction of ethanolic NH3 with C2H5Cl.
(ii) Ammonalysis of benzyl chloride and reaction of amine so formed
with two moles of CH3Cl.
Answer:
Question
C2H5-Cl
NH3 C2H5 – NH2
C2H5 – Cl
H
C2H5 – N – C2H5
–
C2H5 – Cl
H
C2H5 – N – C2H5
–
–
C2H5
C2H5 – Cl (C2H5)4 N+
Cl -
N-Ethylethanamine
N,N- Diethylethanamine
Quaternary
ammoniumchloride

C6H5 – CH2 – Cl
NH3 2CH3 –Cl
C6H5 – CH2 – N –CH3
–
CH3
C6H5 – CH2 – NH2
N,N- Dimethyl benzyl amine

Write Chemical equations for the following conversions :
(i) CH3 – CH2 – Cl into CH3 – CH2 – CH2 –NH2
(ii) C6H5 – CH2 – Cl into C6H5 – CH2 – CH2 –NH2
Answer:
Question
CH3 – CH2 – Cl
Ethanolic NaCN
CH3 – CH2 –C ≡ N
Reduction
CH3 – CH2 – CH2 – NH2
Propannitrile Propan-1-Amine
CH3 – CH2 –C ≡ N

C6H5 – CH2 – Cl
Ethanolic NaCN
C6H5 – CH2 –C ≡ N
H2/Ni
C6H5 – CH2 – CH2 – NH2
Phenylethanenitrile
2- phenylethanamine

Write structure and IUPAC names of :
(i) The amides which gives propanamine by Hoffmann bromamide
reaction.
(II) The amine produced by Hoffmann degradation of benzamide.
Answer:
Question
(1) Propanamine contains three carbons. Hence the amide molecule must
contain four carbon atoms. Structure and IUPAC name of the starting
amide with four carbon atoms are given below.

CH3 – CH2 – CH2 – C –NH2
=
O
(Butanamide)
(ii) Benzamide is an aromatic amide containing seven carbon atoms.
Hence, the amine formed from benzamide is aromatic primary amine
containing six carbon atoms.
NH2 (Aniline or Benzamine)

Physical Properties
 The lower aliphatic amines are gases with fishy (or) Fishy
ammonical odour.
 Primary amines with three or more carbon atoms are liquids and
still higher ones are solids.
 Aniline and other arylamines are usually colourless but get
coloured on storage due to atmospheric oxidation.

Physical Properties
 Lower aliphatic amines are soluble in water because they can form
hydrogen bonds with water molecules.
 Intermolecular association is more in primary amines than in
secondary amines as there are two hydrogen atoms available for
hydrogen bond formation.
 Solubility decreases with increase in molecular mass of amines due to
increase in size of the hydrophobic alkyl part.
 Primary and secondary amines are engaged intermolecular
association due to hydrogen bonding between nitrogen of one and
hydrogen of another molecule.

 Q: Between butan -1 - ol and butan -1 –amine, which is more
soluble in water, Why?
Ans: Alcohols are more polar than amines and form stronger
intermolecular hydrogen bonds than amines. So alcohols are more soluble
than amines.
 Tertiary amines do not have intermolecular association due to the
absence of hydrogen bonding.
 Order of boiling points of isomeric amines is
Primary > Secondary > Tertiary.

H


…….H
H


N
R
H
H



N
H…….
R
H…….


H R

………...
Physical Properties
………...
………...
………...
………...
N

R N


Explain why ethylamine is more
soluble in water whereas aniline
is not soluble.
Ethylamine is soluble in water due to hydrogen bonding.
In aniline due to bulky hydrocarbon part, the extent of
hydrogen bonding is less and hence it is not soluble in
water.

Chemical Reactions
Basic character of amines
Amines react with acids to form salts.
R  NH2 + HX
.. + 
NH2
+ HCl
NH3Cl
.. + 
Aniline Anilinium chloride
Difference in electronegativity between
nitrogen and hydrogen atoms and the
presence of unshared pair of electrons
over the nitrogen atom makes amines
reactive.
R  NH3X (Salt)

Amine salts on treatment with a base like NaOH, regenerate the parent
amine.
RNH3 X + OH
+   
RNH2 + H2O + X
Chemical Reactions

Amines have an unshared pair of electrons on nitrogen atom due to
which they behave as Lewis base.
Larger the value of or smaller the value of p, stronger is the base.
R  NH2 + H2O
+ 
Kb =
+
PKb
= -log Kb
Chemical Reactions
R  NH3 + OH

4) Arrange the following in increasing order of their basic strength :
(i) C2H5NH2, C6H5NH2, NH3, C6H5CH2NH2 and (C2H5)2NH
(ii) C2H5NH2, (C2H5)2NH, (C2H5)3N, C6H5NH2
(iii) CH3NH2, (CH3)2NH, (CH3)3N, C6H5NH2
C6H5CH2NH2

Order of basic strength of amines is
P- nitroaniline < Aniline < P- toluidine
(i) C6H5NH2 < NH3 < C6H5CH2NH2 < C2H5NH2 < (C2H5)2NH
(ii) C6H5NH2 < C2H5NH2 < (C2H5)3N < (C2H5)2NH
(iii) C6H5NH2 < C6H5CH2NH2 < (CH3)3N < CH3NH2 < (CH3)2NH
Answer:

5) Complete the following acid-base reactions and name the products :
(i) CH3CH2CH2NH2 + HCl 
(ii) (C2H5)3N + HCl 
(i) CH3CH2CH2NH2 + HCl CH3CH2CH2NH3 Cl
n – propyl ammonium
chloride
n – propanamine
  + -
(ii) (C2H5)3N+ HCl (C2H5)3NH3 Cl
triethyl ammonium chloride
triethyl amine


_
+

6) Write reactions of the final alkylation product of aniline with excess
of methyl iodide in the presence of sodium carbonate solution.
C6H5NH2 + CH3-I [C6H5NH2 CH3]I
N-methyl anilinium iodide
aniline


-
+
2[C6H5NH2CH3]I + Na2CO3
+ -
2C6H5NHCH3 + 2NaI + CO2 +H2O
Hoffmann’s ammonolysis reaction : In the presence of excess methyl iodide,
aniline (primary amine)forms quaternary ammonium salt.

C6H5NH2
[C6H5N(CH3)2]
N, N-dimethyl aniline
aniline


CH3I
Na2CO3
C6H5N(CH3)2 + CH3 - I [C6H5N(CH3)3]I]
N,N,N-trimethyl anilinium iodide


-
+
[C6H5N(CH3)3]I+Na2CO3
N, N, N-trimethyl anilinium carbonate
+ - +
[C6H5N(CH3)3]2CO3
2-
+ 2NaI

7) Write the chemical reaction of aniline with benzoyl chloride and
write the name of the product obtained:
N H
H

 C
O
Cl
aniline
Benzoyl chloride
+
Base
N+
H
H
C
O-
Cl
N C
H O
N-Phenyl benzamide
HCl +

8) Write the structures of different isomers corresponding to the
molecular formula C3H9N. Write IUPAC names of the isomers
which will liberate nitrogen gas on treatment with nitrous acid:
C3H9N has four isomers
Sol:
(a) CH3CH2CH2NH2
Propan -1- amine
[10
]
(b) CH3CHCH3
NH2
Propan -2- amine
[10
]
(c) CH3NHC2H5
N- methyl ethanamine
[20
]
(d)
CH3
CH3
CH3N
N,N- dimethyl methanamine
[30
]

Primary amines react with HNO2 to produce N2 gas
(a) CH3CH2CH2NH2 + HONO CH3CH2CH2OH + N2 + H2O
Propan-1-ol
Propan-1- amine
(b) + HONO CH3CHCH3 + N2 + H2O
Propan-2-ol
Propan-2- amine
CH3 CHCH3
NH2 OH

1) Intermolecular association is more in…
a) RNH2
b) RNHR
c) R3N
d) N+
(CH3)4

2) Amines acts as:
a) Lewis base
b) Lewis acid
c) Bronsted acid
d) Arrhenius acid

3) Which is not a property of aniline?
a) it is basic in nature
b) it gives carbylamine
c) it can react with alkylhalide
d) it turns blue litmus to red

CHEMICAL PROPERTIES OF AMINES

Alkanamines versus ammonia
Basic character of an amine depends upon the ease of formation of the cation
by accepting a proton from the acid. If the amine forms more stable cation then
the amine is more basic.
R  N

H
H

+ H
+

R  N

H
H

H
H  N

H
H

..
..
+

H  N

H
H

H
H
+
+
+
Basic strength of amines α stability of cation formed.

Order of basicity of amines:
(b)The greater is the size of the ion, lesser will be the solvation and
the less stabilised is the ion. The order of stability of amines is….
a) In gaseous state expected order :
(Due to positive inductive effect )
Tertiary amine > secondary amine > primary amine > NH3
(Due to solvation effect )
10
amine > 20
amine> 30
amine.

Order of basicity of amines:
Due to steric hindrance, solvation effect and positive inductive
effect
c) In aqueous state :
(C2H5)2NH > (C2H5)3N > C2H5NH2 > NH3
(CH3)2NH > CH3 NH2 > (CH3)3N > NH3

Arylamines versus ammonia
 In aryl amines unshared electron pair on nitrogen atom to be in
conjugation with the benzene ring and thus making it less available for
protonation.(due to positive resonance effect).
 Arylamines are less basic than ammonia due to aryl ring which acts as
electron withdrawing group that decreases the electron density on nitrogen .
NH2
..
NH2 NH2
+
-
-
+
NH2
-
+
NH2
..

 In case of substituted aniline, electron releasing groups like increase
basic strength whereas electron withdrawing groups like decrease it.
 Aniline (Five resonating structures) is more stable than
anilinium ion (Two resonating structures).
Stability α no. of resonating structures

Amines undergo alkylation on reaction with alkyl halides
(refer ch. 11 of inter 2 year.)
Alkylation
Why aniline does not undergo
Friedel – Crafts reaction?
Aniline being a Lewis base forms a complex with AlCl3 a Lewis acid.
As a result nitrogen of aniline becomes postively charged and acts as a
strong deactivating group for electrophilic substitution reaction
consequently, aniline does not undergo friedel crafts reaction.
C6H5 NH2 + AlCl3 [C6H5 NH2]+
[AlCl3] -

 Aliphatic and aromatic primary and secondary amines react with acid
chlorides, anhydrides and esters by nucleophilic substitution reaction.
This reaction is known as acylation.
Acylation
 The reaction is carried out in the presence of a base stronger
than the amine, like pyridine, which removes HCl so formed
and shifts the equilibrium to the right hand side.

C2H5 – N – H
H
..
C – Cl
O
CH3
Base
C2H5 – N – C – Cl
H
+
H
O
CH3
_
C2H5 – N – C – CH3
H O
+
H – Cl
Ethanamine
N-ethylethanamide
+

C2H5 – N
C2H5
..
H
+ CH3 – C – Cl
O
Base
C2H5 – N – C - CH3
C2H5
..
O
+ H – Cl
N-Ethyl ethanamine N, N-Diethyl ethanamide
C6H5 – N –H +
H
..
CH3 – C – O
O
– C –CH3
O
C6H5 – N – C - CH3+ CH3COOH
H
..
O
Benzenamine Ethanoic anhydride
Acetanilide

Amines react with benzoyl chloride ).
This reaction is known as Benzoylation.
Methanamine Benzoyl Chloride N - Methylbenzamide
CH3NH2 + C6H5COCl CH3NHCOC6H5 + HCl

Carbyl amine reaction:
Aliphatic and aromatic primary amines on heating with chloroform and
ethanolic potassium hydroxide form isocyanides or carbylamines.
Isocyanide test is used to detect both aliphatic and aromatic primary amines
Heat R  NC + 3KCl + 3H2O
Isocyanide (foul smell)
R NH2 + CHCl3 + 3KOH
(alc)

5. Reaction with nitrous acid
 Primary aliphatic amines react with nitrous acid to form aliphatic
diazonium salts which being unstable, liberate nitrogen gas
quantitatively and alcohols.
H2O
+ 
R NH2 + HNO2
NaNO2 + HCl
[R N2Cl ] ROH + N2 + HCl
273 – 278K
Quantitative evolution of nitrogen is used in
estimation of amino acids and proteins.

 Aromatic amines react with nitrous acid at low temperatures
(273-278 K) to form diazonium salts.
C6H5  NH2
273 – 278K
NaNO2 + 2HCl
C6H5  N2Cl + NaCl 2H2O
+
+ 
Aniline
Benzenediazonium
chloride
Secondary and tertiary amines react with
nitrous acid in a different manner.

6. Reaction with arylsulphonyl chloride
 The reaction of benzenesulphonyl chloride with primary amine
yields N-ethylbenzenesulphonyl amide.
Benzenesulphonyl chloride is
known as Hinsberg’s Reagent
S
=
=
O
O
Cl + 
H N

H
C2H5
S
=
=
O
O
N
H
C2H5 + HCl
N- Ethyl benzene sulphonamide (soluble in alkali)
The hydrogen attached to nitrogen in sulphonamide is strongly acidic due to the
presence of strong electron withdrawing sulphonyl group.
Hence it is soluble in alkali.

With secondary amine, N,N-diethyl-benzene sulphonamide is formed.
Tertiary amines do not react with benzenesulphonyl chloride.
S
=
=
O
O
Cl + 
H  N

C2H5
C2H5 S
=
=
O
O

N

C2H5
C2H5 + HCl
N,N-Diethyl benzene sulphonamide ( insoluble in alkali.)
Hinsberg’s reagent is used to distinguish
10
, 20
and 30
amines.

1) Among the following the most basic compound is :
a) p-nitroaniline
b) acetanilide
c) aniline
d) benzyl amine

2) Carbylamine test is used to detect which one of the following?
a) C6H5CHO
b) C6H5CO2H
c) C6H5NH2
d) C6H5OH

3) The order of basic strength of : (1) C6H5NH2 , (2) C2H5NH2 ,
(3) (C2H5)2NH , (4) NH3 is…..
a) 1 < 4 < 2 < 3
b) 1 < 3 < 2 < 4
c) 4 < 2 < 3 < 1
d) 3 < 2 < 4 < 1

4) The order of basicity of amines in gaseous state is:
a) 10
> 20
> 30
> NH3
b) 30
> 20
> NH3 > 10
c) 30
> 20
> 10
> NH3
d) NH3 > 10
> 20
> 30

ELECTROPHILIC
SUBSTITUTION OF AMINES

7. Electrophilic substitution
a) Bromination:
This is also known as uncontrolled
bromination Reactions
Aniline reacts with bromine water at room temperature to give a white precipitate of
2,4,6-tribromoaniline.
NH2
+ 3Br2
Br2/H2O
NH2
Br
Br Br
+ 3HBr
2,4,6 - Tribromoaniline

Controlled Bromination Reaction :
To prepare mono substituted aniline derivative, group is protected by
acetylation with acetic anhydride, then bromination reaction is carried out
followed by Hydrolysis.
NH2
(CH3CO)2O
Pyridine
Br2
CH3COOH
HN C CH3
=
O
OH or H
+
-
NH2
Br
1
2
3
HN C CH3
=
O
Br (4 –bromoaniline)
(major)

The lone pair of electrons on nitrogen of acetanilide interacts with
oxygen atom due to resonance.
The lone pair of electrons on nitrogen is less available for donation to
benzene ring by resonance. Therefore, activating effect of group is less
than that of amino group.
-
+
O
..
 CH3

..
..
O
N C CH3
=
..
..
..
N = C

b) Nitration:
 Nitration of Aniline gives ortho, para and meta nitro aniline .
 Meta nitroaniline is due to formation of anilinium ion which is
metadirecting.
+
+
(51%) (47%) (2%)
HNO3,H2SO4, 288K
NH2
NO2
NH2
NO2
NH2
NO2
NH2

Controlled Nitration Reaction: To prepare mono substituted aniline
derivative, group is protected by acetylation with acetic anhydride,
then Nitration reaction is carried out followed
by Hydrolysis.
(CH3CO)2O
Pyridine
HNO3, H2SO4, 288K
Acetanilide
OH or H
+
-
NH2 NH
NHCOCH3
NO2 NO2
NH2
P-Nitroacetanilide P-Nitroaniline
COCH3
288K

c) Sulphonation:
Aniline reacts with concentrated sulphuric acid to form anilinium
hydrogensulphate which on heating with sulphuric acid at 453-473K
produces p-amino benzene sulphonicacid, commonly known as
sulphanilic acid, as the major product.
Zwitter ion has both positive and
negative charges.

H2SO4
453 - 473
K
+
-
+ -
NH3HSO4
NH2
SO3H
NH3
SO3
Anilinium hydrogen sulphate
Sulphanilic acid
Zwitter ion
NH2
..

 Aniline does not undergo friedel-crafts reaction(alkylation and acetylation)
due to salt formation with aluminium chloride, the lewis acid,
which is used as a catalyst. Due to this nitrogen of aniline acquires positive
charge and hence acts as a strong deactivating group for further reaction.

CONVERSIONS
:
(i) C6H5N2Cl
CuCN
A
H2O/H+
B
NH3
 C
A = C6H5CN
B = C6H5COOH
C = C6H5CONH2

NH2
Aniline
NHCOCH3
Acetanilide
(CH3CO)2O
CH3COCl
(ii) ANILINE TO P- BROMOANILINE
P-bromo acetanilide
Br2/CH3COOH
NHCOCH3
Br
H2O/OH-
P-bromo aniline
NH2
Br

1) Zwitter ion can be formed by….
a) Acetanilide
b) Benzanilide
c) Sulphanilic acid
d) Benzene sulphonamide

2) Aniline (1 mole) react with bromine to give symmetrical
tribromoaniline. The amount of bromine required is….
a) 3.0 moles
b) 1.5 moles
c) 4.5 moles
d) 6.0 moles

3) Aniline reacts with … to yield … as the final product:
a) Bromine, 2-bromoaniline
b) Bromine water; 2,4,6 - tribromoaniline
c) Chlorofrom/KOH, phenyl cyanide
d) Acetyl chloride, benzanilide

METHODS OF
PREPARATION OF
DIAZONIUM SALTS

Diazonium Salts
 The diazonium salts are represented by general formula ,
where stands for the aryl group and X may be any anion such as
etc.
 They are named by adding the suffix diazonium to the parent
compound and is further followed by the name of the anion.
The group is called diazonium group

Ex: C6 H5
Ex: C6 H5
Diazonium Salts
 Primary aliphatic amines form highly unstable alkyldiazonium salts.

 Primary aromatic amines form arenediazonium salts which are
stable
for a short time in solution at low temperatures (273 - 278 K).
 The stability of arene diazonium ion is explained on the basis of resonance.

N  N: 
N = N:
:

N = N:
:

N = N:
:




Diazonium Salts
N2Cl-
+
Benzene
diazonium
chloride
Benzene
diazonium
hydrogen
sulphate
P-toluene
diazonium
hydrogen
sulphate
P-nitrobenzene
diazonium
fluoroborate
+ -
N2HSO4
+ -
N2HSO4
CH3
+ -
N2BF4
NO2

Method of Preparation of Diazoniun Salts
 Benzenediazonium chloride is prepared by the reaction of aniline
with nitrous acid at 273 - 278K.
 The conversion of primary amine into a diazonium salt is called
diazotisation.

C6H5N2Cl + NaCl + 2H2O
273-278K
-
+
C6H5NH2 + NaNO2 + 2HCl
or HNO2
Due to its instability, the diazonium salt is not generally stored and is used
immediately after its preparation.

 Benzenediazonium chloride is a colourless crystalline solid.
Physical Properties
 It is readily soluble in water and is stable in cold but reacts with
water when warmed.
 It decomposes easily in the dry state.
Benzene diazonium fluoroborate is water insoluble and stable at
room temperature.

Chemical Reactions
Reactions involving displacement of nitrogen:
 Diazonium group being a very good leaving group, is substituted by
other groups such as , , , ,
which displace nitrogen from the aromatic
ring.
The nitrogen formed escapes from the reaction mixture as a gas.

ArX
CuBr/HBr
CuCl/HCl
CuCN/Cu
Ar Br + N2
Ar Cl + N2
Ar CN + N2
-
The nucleophiles can easily be introduced in the benzene ring in the
presence of ion.
This reaction is called Sandmeyer reaction.
1. Replacement by halide or cyanide ion:
Where Ar =

 Chloride or bromide can also be introduced in the benzene ring by
treating the diazonium salt solution with corresponding halogen acid
in the presence of copper powder. This is referred as Gatterman
reaction.
ArN2X
Cu/HCl
Cu/HBr
ArCl + N2 + CuX
ArBr + N2 + CuX
+ -
 The yield in Sandmeyer reaction is found to be better than
Gattermann reaction.

Replacement by iodide ion:
ArN2Cl
+ -
+ KI
Warm
ArI + N2 + KCl
Replacement by fluoride ion:
ArN2Cl
+ -
+ HBF4
-HCl ArN2BF4
+ - 
Ar – F + N2 + BF3
Replacement by H:
ArN2Cl
+ - + H3PO2 +H2O ArH + N2 + H3PO3+HCl
ArN2Cl
+ -
+ CH3CH2OH ArH + N2 +CH3CHO+HCl
(Fluoroboric acid)

Replacement by hydroxyl group
Replacement by group:
H2SO4
(Boiling)
HBF4
-HCl
NaNO2
Cu,
NO2
N2Cl
+ - N2BF4
+ -
ArN2X
+ -
+ H2O Ar – OH + N2 +
HX
Phenol
Nitrobenzene
+ N2+NaBF4

1) Replacement of –N2
+
X-
group by or or is called
a) Diazo coupling
b) Hoffmann reaction
c) Sandmeyer reaction
d) Perkin reaction

2) Action of HCl on Benzene diazouium chloride in the presence of
copper powder gives….
a) P-chloro benzene diazonium chloride
b) O-chloro benzene diazonium chloride
c) Chloro benzene
d) O-dichloro benzene

3) Benzene diazonium fluoro borate on heating to dryness yields….
a) Fluoro benzene
b) Benzene
c) Aniline
d) O-fluoro aniline

COUPLING REACTIONS

 The azo products obtained have an extended conjugate system
having both the aromatic rings joined through the bond.
Reactions involving retention of diazo group (coupling reactions:)
 Benzene diazonium chloride reacts with phenol in which the phenol
molecule at its para position is coupled with the diazonium salt to form
p-hydroxyazobenzene .
This type of reaction is known as coupling reaction.
 These compounds are often coloured and are used as dyes.
 The reaction of diazonium salt with aniline yields p-aminoazobenzene.
This is an example of electrophilic substitution reaction.

Reactions involving retention of diazo group coupling reactions:
+ NN OH+ + H2O
+
H
NN H2O +
NN
+
NN
+
H OH
H NH2
NH2 +
OH
P-Hydroxyazobenzene (orange dye)
P-aminoazobenzene (yellow dye)

Importance of diazonium Salts in Synthesis of Aromatic Compounds
 The diazonium salts are very good intermediates for the introduction of
groups into the aromatic ring.
Aryl fluorides and iodides cannot be
prepared by direct halogenation.

 The replacement of diazo group by other groups is helpful in preparing
those substituted aromatic compounds which cannot be prepared by
direct substitution in benzene or substituted benzene.
 The cyano group cannot be introduced by nucleophilic substitution of
chlorine in chlorobenzene but cyanobenzene can be easily obtained from
diazonium salt.
Importance of diazonium Salts in Synthesis of Aromatic Compounds

Conversion
s
How will you convert 4 – nitrotoulene to 2- bromobenzoic
acid?
CH3
NO2
Br2
Sn/HCl
NO2
CH3
Br
NH2
CH3
Br
NaNO2/HCl
273-278K
N2Cl
CH3
Br
H2O
H3PO2
COO
H Br
CH3
Br
KMnO4
𝑶𝑯−

Conversion
s
Convert : (i) 3-methyl aniline to 3- nitrotoluene;
(ii) Aniline to 1,3,5-tribromobenzene.
Sol: (i) 3-methyl aniline to 3-nitrotoluene
NaNO2
Cu,Heat
NH2
CH3
3-methyl aniline
Diazotisation
NaNO2/HBF4
Diazonium salt
N2BF4
CH3
+ -
NO2
CH3
3-nitrotoluene

Conversion
s
Convert :(ii) Aniline to 1,3,5-tribromobenzene.
Sol:
NH2
Aniline
Bromination
Br2/H2O
Diazotisation
NaNO2/HCl
Br
NH2
Br Br
Br
N2Cl
Br Br
+ -
Br
Br
Br
2,4,6 Tribromo aniline Diazonium salt
1,3,5 Tribromo benzene
H3PO2+ H2O

1) Which of the following is the correct order of ease of coupling
with C6H5N2Cl ?
a) A > D > B > C
b) C > A > B > D
c) C > A > D > B
d) B > D > A > C
A) Benzene B) Nitro benzene
C) Phenol D) Chloro benzene

2) Coupling of phenol with benzene diazonium salt yields….
a) O-hydroxy derivative of salt
b) P-hydroxy derivative of salt
c) m-hydroxy derivative of salt
d) A mixture of a,b and c

INTRODUCTION OF CYANIDES

Cyanides and Isocyanides
Hydrogen cyanide is known as hydrocyanic acid and hydrogen cyanide
have two Isomeric forms.
HCN HN  C
Hydrogen isocyanide
Hydrogen cyanide
Structure of cyanides and isocyanides
Hence it forms two types of isomeric forms (cyanides and
Isocyanides)

R  C  N
alkyl isocyanides
alkyl cyanide
Difference between cyanides and isocyanides
Alkyl cyanides are polar compounds.
In cyanides alkyl group is attached to the carbon of cyanide ion and nitrogen
is present at the end while in isocyanides alkyl group is linked to N and the
carbon atom at the end.
The cyanide ion CN: has one unshared pair of electrons on both ends .
R N  C

Nomenclature
Alkyl cyanides are also known as nitriles of the acid. They produce
carboxylic acid on hydrolysis.
Hence HCN is named as formonitrile.
HCOOH
formic acid
H2O
Ex: HCN

FORMULA AS CYANIDE AS ACID
NITRITE
IUPAC NAME
HCN
Hydrogen
cyanide
Formo nitrile Methan nitrile
CH3CN Methyl cyanide Acetonitrile Ethan nitrile
CH3CH2CN Ethyl cyanide Propionitrile Propan nitrile
(CH3)2CHCN
Isopropyl
cyanide
Isobutyronitrile 2-methyl propan
nitrile
CH2 =CHCN Vinyl cyanide Acrylo nitrile
Prop-2-en-1-
nitrile

Preparation
Isocyanides (Isonitriles or Carbyl amines) are named as alkyl isocyanides or
alkyl isonitriles or alkyl carbyl amines.
Ex: (C  NC )
Methyl isocyanides or methyl carbyl amine or methyl isonitrile.
(Major)
C  Cl
KCN
Ethanolic
C  CN + C NC
C  NC+ C  CN
Methyl cyanide
Methyl isocyanide
From Alkyl halides:
Ethanolic
AgCN
Methyl isocyanide
(Major) (Minor)
Methyl cyanide
(Minor)

1) Acetonitrile has the structure:
a) C2H5NC
b) C2H5CN
c) CH3NC
d) CH3CN

2) When methyl cyanide is hydrolysed in presence of alkali, it
forms….
a) acetamide
b) methane
c) CO2 + H2O
d) acetic acid

3) Acetonitrile on reduction gives:
a) Propanamine
b) Methanamine
c) Ethanamine
d) Both a and b

PREPARATION OF
CYANIDES AND ISOCYANIDES

From Amides The dehydration of primary amides yields nitriles.
C  C  N
=
O
+ Cl
Pyridine
c
C  CN + H +HCl
(Acetamide)
C  CN
The reaction is run in pyridine, which takes up the two acids in the
form of their pyridine salts.
P2O5 may be used as dehydrating agent but not convenient to
handle.

ALDOXIMES
The dehydration of aldoximes with acetic anhydride gives nitriles.
C-CH2 -CN
propanaldoxime
2CCOOH
Ethyl cyanide
ISOCYANIDES
Preparation of isocyanides
amines reacts with chloroform and alkali gives isocyanides.
+
C-CH2 - CH = NOH + (C-CO)2O
FROM AMINES

R  N R - NC + 3 KCl +3H2O
heat
PHYSICAL PROPERTIES
+ CHC + 3KOH
 Cyanides are fairly polar compounds but they are less soluble in
water than amines.
 Nitriles higher than propionitrile are only slightly soluble in water.
Isocyanide
They are much weaker bases than amines too, therefore
they are not soluble in aqueous acids.

 Alkyl cyanides have pleasant odour and are slightly toxic, in contrast
to isocyanides which have very bad odour and highly toxic.
 Isocyanides boil at low temperatures than their isomeric cyanides.
 However both isomers are more polar than alkyl halides, hence their
boiling points are higher than the corresponding alkyl halides.
 Cyanides have more polar character than isocyanides,
hence cyanides have high B.P and more soluble in water .

CHEMICAL REACTIONS
Hydrolysis
Cyanides on hydrolysis gives carboxylic acids and ammonia.
R  C≡ N + 2O
H3 O+
−𝑵𝑯𝟑
R  C - OH → R - COOH +
H2O
OH
OH

1) Ethyl isocyanide on hydrolysis in acidic medium gives….
a) Ethanoic acid and ammonium salt
b) Propanoic acid and ammonium salt
c) Ethylamine salt and methanoic acid
d) Methylamine salt and ethanoic acid

Isocyanides on hydrolysis gives amines and formic acid.
R  NC
+
H3 O+
O
R  N + HCOOH
Addition of Grignard
reagent
R  CN R  C = NMgX

H3 O+
R  C 
=
O
+ 2
+ + N

REDUCTION
 Nitriles on reduction gives - amines.
R  CN
 Isocyanides on reduction gives - amines.
LiAl
R  C N
R  NC
Na  Hg
R  N C
()
()
Na in alcohol (or) H2/catalyst
H2/catalyst

Oxidation with HgO
HgO being mild oxidising agent converts isocyanides to isocyanates.
R  N  C
Alkyl isocyanides
+ Hg
+ R  N = C = O
Alkyl isocyanate
Conversion
(ii) COOH
Benzoic acid
CONH2
Benzamide
NH3
Cyano Benzene
CN
H2O/H+

USES
 Cyanides are more important intermediates in multistep synthesis in
the laboratory.
Cyanides are used in the production of nitrile rubbers, synthetic
textiles and acrylonitrile (Vinyl cyanide).

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