Chemical Properties of Nitro Compounds and Properties

Chemical Properties of Nitro Compounds and Properties

→ Reduction : Reduction takes place in different steps. The final product, however depends upon the reaction medium and nature of the reducing agent.

Chemical Properties of Nitro Compounds and Properties 1

Acidic Medium :

Chemical Properties of Nitro Compounds and Properties 2

Neutral Medium :

Chemical Properties of Nitro Compounds and Properties 3

Basic Medium :

Chemical Properties of Nitro Compounds and Properties 4

→ Electrolytic Reduction : In electrolytic reduction nitrobenzene forms paminophenol by rearrangement in the presence of weak acid or base.

Chemical Properties of Nitro Compounds and Properties 5
Chemical Properties of Nitro Compounds and Properties 6

Catalytic reduction :

Chemical Properties of Nitro Compounds and Properties 7

→ Reduction with Metallic Hydride :

Chemical Properties of Nitro Compounds and Properties 8

→ Selective Reduction : Selective reduction is the reduction of one NO2 group from two group present in compound into NH2.

Chemical Properties of Nitro Compounds and Properties 9

→ Hydrolysis : Primary nitro alkanes when heated with conc. HCl or 85% H2SO4 then the salt of carboxylic acid and hydroxylamine is formed.

Chemical Properties of Nitro Compounds and Properties 10
Chemical Properties of Nitro Compounds and Properties 11

2° nitroalkane when heated with HCl forms ketone and nitrous acid.
3° nitroakane do not hydrolyse.

→ Reaction with HNO2 : Primary nitroalkane having α — H atom reacts with HNO2.

Chemical Properties of Nitro Compounds and Properties 12

→ 1° nitroalkane reacts with HNO2 and forms nitrolic acid which dissolve in base and form red colour solution

Chemical Properties of Nitro Compounds and Properties 13

→ Secondary nitroalkane having α — H reacts with HNO2 and form pseudonitrol whose colour is blue and it is insoluble in base.

→ 3° nitroalkane does not react therefore this reaction is used for differentiation among 1°, 2° and 3° nitroalkane.

→ Halogenation : Primary and secondary nitroalkane having α — H reacts with halogen in presence of NaOH.

Chemical Properties of Nitro Compounds and Properties 14

Ring substitution reaction of nltrobonzene : stable nitrobenzene gives two type of reaction

  • Electrophilic Substitution Reactions
  • Nucleophilic Substitution Reactions

→ Electrophilic Substitution Reactions : Nitro group in nitrobenzene is m-directive and deactivating group. Which can be represented in the following resonating structures:

Chemical Properties of Nitro Compounds and Properties 15

→ Due to —I effect and —M effect of NO2 group, electron density decreass at ortho and para position of ring.

→ That’s why nitrobenzene is less reactive for electrophilic reaction.

→ But electron density is high at m-position so electrophile attacks on mcta position.

Chemical Properties of Nitro Compounds and Properties 16

→ Nucleophilic Substitution reaction : According to resonance structure of nitrobenzene, positive charge comes on o-and p-position hence nucleophile attacks on o-and p-position. Hence nitrobenzene is o-and p-directive.

Chemical Properties of Nitro Compounds and Properties 17

Chemistry Notes