The NO2 group attached with organic chain is called as nitro functional group. All the compounds containing the nitro functional group are called as organic nitro compounds.

1. Nitro Compounds
DR. TANUJA NAUTIYAL
DEPT OF CHEMISTRY
NORTHERN INDIA ENGINEERING
COLLEGE

2. • Organic compounds containing nitrogen can be
broadly classified into two groups.
• Compounds containing nitro functional group -
NO2
• Compounds containing amine functional group -
NH2 and their derivatives.
• In this nitro compounds are primary source of
organic compounds with functional group -NO2 to
start the synthesis of many other important
compounds
Nitro Compound

3. • The NO2 group attached with organic chain is
called as nitro functional group.
• All the compounds containing the nitro
functional group are called as organic nitro
compounds.
They are classified as
• Aliphatic nitro compounds
• Aromatic nitro compounds
Nitro Compound

4. Aliphatic Nitro Compounds
• If the nitro functional group is attached with
aliphatic carbon chain it is called as aliphatic nitro
compound.
• They are weakly acidic due to their azinitro form
and they are soluble in alkalies and can undergo
condensation reaction with aldehydes.
CH3-NO2 - Nitro methane.

5. Aromatic Nitro Compounds
• If the nitro functional group is attached with
benzene ring it is called as aromatic nitro
compound.
• All aromatic nitro compounds are yellow
colored liquids which may change to dark
brown color due to oxidation.

6. • The NO2 group is called as nitro group.
• It is electron withdrawing group due to its -
Inductive effect as well as -Resonance effect.
Nitro Compound

7. Nomenclature of Nitro Compounds
• Organic compounds containing nitro -
NO2 functional group are called as nitro
compounds.
• They are obtained by replacing one or more
hydrogen in the hydrocarbon with nitro group.
Here, the nitrogen is directly attached to the
carbon atom in the organic chain.

8. Nomenclature of Nitro Compounds
• The general formula of nitro compounds is
• Nitro compounds are named by prefixing the
nitro with the root alkane name with the
locant.
• CH3NO2 is amino methane
• CH3-CH(NO2)-CH3 is 2-nitropropane

9. General method of preparation
1. Nitration of alkanes
2. From alkyl halides
3. From salts of α-halogeno carboxylic acid
4. From primary amines
5. From a-nitroalkenes
6. From oximes

10. By direct nitration of alkanes
Alkanes are treated with nitrating mixture
(fuming nitric acid) with concentrated sulfuric
acid to give nitro compounds. This method will
not give good yield in case of aliphatic nitro
compounds, but will give best yield for aromatic
nitro compounds like nitro benzene.
Ethane on nitration gives nitro ethane.
CH3-CH3 + HNO3/H2SO4 → CH3-CH2-NO2

11. From alkyl halides
• By treating iodoalkanes with silver nitrite
• Iodo alkanes on reacting with silver nitrite give
nitro compounds. This method will not give good
yield for nitro benzene. But all the aliphatic nitro
compounds can be prepared by this method.
For example iodoethane on treating with silver
nitrite gives nitroethane.
CH3-CH2-I + AgNO2 → CH3-CH2-NO2 + AgI

12. By treating amines with alkaline
KMnO4
• Tertiary amines on treating with alkaline
KMnO4 gives tertiary nitro compounds. This
method works only with tertiary amines.

13. Physical Properties of Nitro Compounds
• Aliphatic nitro compounds are mostly gaseous
in nature and higher members are liquids.
• Aromatic nitro compounds are yellow color
liquids which intensified to brown color by
time.
• They are polar due to the presence of nitro
group.

14. Isomerism in Nitro Compounds
• The isomerism exhibited by organic nitro compounds
can be classified into the following types.
1. Chain isomerism
•
Compounds having same molecular formula and
difference in the nature of carbon chain is called as
chain isomers. For example 1-nitro butane and 2-
methyl 1-nitro propane.
CH3-CH2-CH2-CH2-NO2 CH3-CH(CH3)-CH2-NO2

15. • 2. Position isomerism
• Compounds having same molecular formula
and difference in the position of attachment
of functional group is called as position
isomers. For example 1-nitro propane and 2-
nitro propane.
• CH3-CH2-CH2-NO2
• CH3-CH(NO2)-CH3
Isomerism in Nitro Compounds

16. • 3. Functional group isomers
• Nitro compounds are functional group isomers
for nitrite compounds in which the oxygen is
bonded with the carbon chain. The following
diagram explains the difference between nitro
methane and methyl nitrite.
Isomerism in Nitro Compounds

17. • 4. Tautamerism
• In solution the nitro form is in equilibrium
with azinitro form. The azinitro form is acidic
in nature and hence nitro methane is soluble
in alkalis.
Isomerism in Nitro Compounds

18. Nitro compounds undergo tautomerism in
solution to azinitro form, which is acidic in
nature.
Hence, all the nitro compounds are weakly
acidic in nature.
Chemical Properties of Nitro
Compounds

19. • They dissolve in bases to give salts and can
be regenerated by adding a stronger acid like
HCl.
• Similarly they can be reduced to amino
compounds in acidic or basic medium.
Chemical Properties of Nitro
Compounds

20. Reaction of nitroalkane
1. Reduction
2. Hydrolysis
3. Halogenation
4. Reaction with nitrous acid
5. Condensation with aldehydes and ketones
Chemical Properties of Nitro
Compounds

21. 1. Reduction of aliphatic nitro compounds
Aliphatic nitro compounds can be reduced to
amines by treating with Sn/HCl. This is the
effect way to convert nitro compounds to
amines.
CH3NO2 →→ CH3NH2
Chemical Properties of Nitro
Compounds

22. Aliphatic nitro compound can be reduced to
hydroxyl amines by treating with diborane.
CH3NO2 →→ CH3NHOH
Aliphatic nitro compounds are reduced to oximes
using stannous chloride.
CH3NO2 →→ CH3-N = OH
Chemical Properties of Nitro Compounds

23. Reduction of aromatic nitro compounds
• Nitro benzene can be reduced to aniline by
Sn/HCl.
On treating with Raney Nickle, nitro benzene is
reduced to phenyl hydroxylamine.

24. Uses of nitro compounds
• They are useful intermediates in the preparation
of amino compounds and diazonium salts which
are synthetic important materials to prepare
almost all organic compounds.
• Nitro benzene is used in shoe and floor polishes.
• It is also used in paint and solvents and to mask
unpleasant odor in chemicals.
• They are used to prepare the azo-dyes and in soil
sterility.
• It is used in the manufacture of Paracetamol (a
popular analgesic)

25. THANK YOU
DR. TANUJA NAUTIYAL
DEPT OF CHEMISTRY
NORTHERN INDIA ENGINEERING
COLLEGE