BENZENE

Introduction of Benzene

Benzene and all those compounds which resemble benzene in their chemical behavior are

termed aromatic. Benzene is an aromatic compound with a molecular formula of C₆H₆. The

benzene molecule comprises six carbon atoms joined in a planar ring with one hydrogen

atom attached. Benzene is a hydrocarbon because it contains only carbon and hydrogen atoms.

Benzene is a chemical that is a colorless or light-yellow liquid at room temperature. It has a

sweet odor and is highly flammable. Benzene evaporates into the air very quickly. Its vapor is

heavier than air. Benzene dissolves only slightly in water and will float on top of water.

Nomenclature of Derivatives of Benzene: –

In IUPAC nomenclature, there are various rules for naming benzene derivatives. These are as

follows: –

For Monosubstituted benzene derivatives: –

Monosubstituted benzene derivatives are compounds in which another functional group or atom replaces a single hydrogen atom on the benzene ring. Here are some common monosubstituted benzene derivatives:

1. Toluene (Methylbenzene, C₆H₅CH₃):

Substituent: Methyl group (-CH₃).

It is commonly used as a solvent and as a starting material in synthesizing various chemicals.

1. Phenol (C₆H₅OH):

Substituent: Hydroxyl group (-OH).

Used in the production of resins, plastics, and pharmaceuticals.

• Aniline (C₆H₅NH₂):

Substituent: Amino group (-NH₂).

Used in the synthesis of dyes, pharmaceuticals, and rubber chemicals.

• Nitrobenzene (C₆H₅NO₂):

Substituent: Nitro group (-NO2).

Used in the production of aniline and as a solvent.

• Benzaldehyde (C₆H₅CHO):

Substituent: Formyl group (-CHO).

Used in the synthesis of perfumes, dyes, and flavouring agents.

• Benzoic Acid (C6H5COOH):

Substituent: Carboxyl group (-COOH).

Used as a food preservative and in the synthesis of chemicals.

• Chlorobenzene (C6H5Cl):

Substituent: Chlorine atom (-Cl).

Used as a solvent and in the production of other chemicals.

• Bromobenzene (C6H5Br):

Substituent: Bromine atom (-Br).

Used in organic synthesis and as a solvent.

• Iodobenzene (C6H5I):

Substituent: Iodine atom (-I).

Used in organic synthesis and as a reagent in chemical reactions.

• Fluorobenzene (C6H5F):

Substituent: Fluorine atom (-F).

Used in organic synthesis and as a solvent.

These monosubstituted benzene derivatives have diverse applications in the chemical industry, including the production of pharmaceuticals, polymers, dyes, and various specialty chemicals. These compounds’ specific properties and reactivities depend on the nature of the substituent attached to the benzene ring.

For Disubstituted Benzene Derivative: –

Disubstituted benzene derivatives are compounds in which different functional groups or atoms replace two hydrogen atoms on the benzene ring. Here are some common examples of disubstituted benzene derivatives:

1. Ortho-dimethylbenzene (1,2-dimethylbenzene or o-xylene):

Substituents: Two methyl groups (-CH3) in the ortho positions.

Used as a solvent and in the production of polymers.

2. Meta-dimethylbenzene (1,3-dimethylbenzene or m-xylene):

Substituents: Two methyl groups (-CH3) in the meta positions.

Used in the production of resins, polymers, and as a solvent.

3. Para-dimethylbenzene (1,4-dimethylbenzene or p-xylene):

Substituents: Two methyl groups (-CH3) in the para positions.

Used in the production of terephthalic acid for polyester fibers.

4. Dichlorobenzene (1,2-dichlorobenzene):

Substituents: Two chlorine atoms (-Cl) in the ortho positions.

Used as a solvent and in the manufacturing of pesticides.

5. Dimethyl aminobenzene (N, N-dimethylaniline):

Substituents: Methyl group (-CH3) and amino group (-NH2) in the para positions.

Used in the synthesis of dyes and pharmaceuticals.

6. Dinitrobenzene (1,3-dinitrobenzene):

Substituents: Nitro groups (-NO2) in the meta positions.

Used in the production of dyes and as a chemical intermediate.

7. Dibromobenzene (1,4-dibromobenzene):

Substituents: Bromine atoms (-Br) in the para positions.

Used in organic synthesis and as a building block for various compounds.

8. Diethylbenzene (1,2-diethylbenzene):

Substituents: Two ethyl groups (-C2H5) in the ortho positions.

Used in the production of specialty chemicals.

These disubstituted benzene derivatives exhibit different chemical and physical properties based on the specific arrangement of substituents on the benzene ring. They find applications in various industrial processes, including synthesizing polymers, pharmaceuticals, and specialty chemicals.