Helo, reders welcome to “textilesgreen.in” today I m going to explain about Nitrobenzene with latest and interesting information.
What is Nitrobenzene
It is an organic compound. it is also called aromatic nitro compound.
It is also industrial chemical compound.
The Chemical formula of nitrobenzene is C6H5-NO2.
It is insoluble in water, ether alcohol but it is soluble in acetone, acitic acid.
It is pale yellow oil liquid aromatic compound.
It is freezes to give greenish-yellow crystals. it is produce large scale from benzene.
it is prepared by treating benzene with a mixture of nitric and sulphuric acid.
In other words, it is prepared by nitration of benzene with concentration of nitric acid and sulphuric acid.
In case of preparation, during reaction one Hydrogen in the benzene molecule is replaced with group NO2.
Properties of nitrobenzene
- Chemical formula – C6H5-NO2
- Molar mass – 123.11 g/mol
- Boiling point – 210.9°C
- Melting point – 5.7°C
- Density – 1.2 g/cm3
- Class type – aromatic nitro compound
- Product colour – greenish yellow oily
- Product insoluble – water, ether, alcohol
- Product soluble – acetone, acetic acid
- Nitrobenzene reaction are completed due to NO2 group and the ring.
- In this case of, C-NO2 bond is very strong and it is not replaced OH group.
- But in this case, 1 Hydrogen in the benzene molecule is replaced with group NO2.
- Nitrobenzene undergoes electrophilic substitution at meta position.
Prepration of nitrobenzene
- Chemical reaction method.
- Laboratories methods.
- Chemical reaction methods
When benzene is react with nitric acid in the presence of sulphuric acid then it give (C6H5-NO2) as a product.
C6H6 + HNO3 _H2SO4 – C6H5-NO2 + NO2 benzene nitric acid nitrobenzene
In this reaction, when benzene are react with nitric acid then NO2 from nitric acid will attached with benzene. and it make C6H5-NO2. These are the first step of this reaction.
C6H5 + NO2
In second step, one Hydrogen from Benzene and one Hydrogen + one oxygen from nitric acid are replaced and it make water molecule.
H+H+O = H2O (water molecule)
Now, I can say that, the final product are given from this reaction is C6H5-NO2 and water.
C6H5-NO2 + H2O.
Lab preparation method
lets get started,
Nitration of nitrobenzene
When you want to do nitration of benzene then first of all it is necessary to select reagent such as;
HNO3 (nitric acid)
You know that nitric acid is the best reagent for nitration.
Nitric acid are play better role in nitration of nitrobenzene.
When nitrobenzene is react with nitric acid in the presence of concentration of sulphuric acid then it give meta dinitrobenzene and water.
Again, meta dinitrobenzene is react with HNO3 in the presence of H2SO4 then it give 1,3,5 meta trinitrobenzene as a product.
Reduction of nitrobenzene
reduction of nitrobenzene is carried out with different medium such as,
- Acidic medium
- Neutral medium
- Alkaline medium
Here, I m going to explain about reduction of nitrobenzene with the help of different medium.
Lets get started,
- Acidic medium
When C6H5-NO2 is react with the presence of zn/HCl (acidic medium) then it give aniline.
2. Neutral medium
When C6H5-NO2 is react with the presence of zn/NH4Cl then it give
3. Alkaline medium
When C6H5-NO2 is react with the presence of zn/NaOH (alkaline medium) then it give
4. Alkaline medium
When C6H5-NO2 is react with the presence of Fe/NaOH (alkaline medium) then it given
Resonance structure of nitrobenzene
According to first structure, first nitrogen are attached on benzene and one oxygen is attached with double bond and one oxygen is attached with single bond.
you know that oxygen have more electronegative compare with Nitrogen so, oxygen is pull electro from double bond and nitrogen get + charge (nitrogen have less electron).
Now, according to second structure, nitrogen have low electron density the nitrogen try to get electron. so, bond are sift up and then nitrogen get electron. So, both oxygen have negative charge.
Similarly, all structure work on the basis of single bond, double bond, and + charge.
You know that, in resonance structure coordinate bond will not show.
Resonating has be done with the help of conjugation single bond, double bond and positive charge.
In resonance structure, 1 structure and 5 structure is same. It mean final structure and 1st structure is same.
So, the final nitrobenzene structure is formed from resonating.
If I m talking about overall results then the partial double bond passing in benzene ring as well as in single bond oxygen or double bond oxygen as shown in figure.
It mean, partial double bond are make circle in benzene ring.
Finally, it make Partial positive charge on artho position and partial positive charge on Pera position. It mean electron density is low on both position (artho, Pera).
So, the next electrophile will attack on meta position. So, nitrobenzene is called meta directing.
- This product (C6H5-NO2) is windly used for preparation of different types of dyes.
- aniline dyes are prepared from nitrobenzene.
- It is also be used for preparation of cosmetic product such as, perfumes.