Chlorobenzene: Preparation, Properties and uses

Chemistry Page
3 min readNov 30, 2020

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Chlorobenzene formula and structure

Preparation

Laboratory Method

Aniline: Benzenediazonium chloride is obtained by replicating aniline with a mixture of NaNO2 and HCl at 0–5°C. Chlorobenzene is obtained by heating benzenediazonium chloride in the presence of cupreous chloride and hydrochloric acid.

C6H5NH2 + NH2 + HCl → C6H5 — N = N — Cl + 2H2O

The first reaction is called diazotization reaction and the second reaction is called sandmeyer reaction.

Read more about diazotization reaction and sandmeyer reaction

C6H5 — N = N — Cl → C6H5Cl + N2

Industrial Method

Chlorobenzene is obtained by mixing a mixture of benzene vapors, hydrogen chloride gas and oxygen (oxygen) at 250°C on a copper oxide catalyst. This reaction is used for the industrial manufacture of chlorobenzene. This method of industrial manufacture of chlorobenzene is called Rasching method.

2C6H6 + 2HCl + O2 → 2C6H5Cl + 2H2O

Physical properties

chlorobenzene is a colorless, volatile and aromatic liquid. Its boiling point is 132°C. It is insoluble in water and soluble in alcohol and ether. It is heavier than water and its relative density is 1.12.

Chlorobenzene Boiling point

The reaction of Chlorine Atom

Reaction with NaOH: phenol is obtained by heating chlorobenzene with aqueous NaOH at about 300°C.

C6H5Cl + NaOH → C6H5OH + NaCl

Reaction with Ammonia: Aniline is obtained by heating chlorobenzene with ammonia at high pressure and around 250°C in the presence of Cu2O.

C6H5Cl + NH3 → C6H5NH2 + HCl

Aniline is also obtained when chlorobenzene is reacted with NaNH2 or KNH2 in a fluid ammonia solution.

C6H5Cl + NaNH2 → C6H5NH2 + NaCl

Reaction with cuprous cyanide: Phenyl cyanide (benzonitrile) is obtained by heating chlorobenzene with cuprous cyanide (CuCN) at about 250°C in the presence of pyridone.

C6H5Cl + CuCN → C6H5CN + CuCl

Reduction: On the reaction of chlorobenzene with Na — Hg and water, it is reduced and benzene is obtained. This reaction can also be carried out by Ni Al alloy and NaOH.

C6H5Cl + 2H → C6H6 + HCl

Halogenation: A mixture of ortho and para diChlorobenzene is obtained when chlorine is reacted with chlorine in the absence of sunlight and in the presence of halogen carrier.

Nitration: A mixture of ortho and para chloro nitrobenzene is obtained by the reaction of chlorobenzene with concentrated HNO3 and concentrated H2SO4.

Sulfuration: A mixture of ortho and para Chlorobenzene sulfonic acid is obtained by the reaction of Chlorobenzene with the corresponding H2SO4.

Reaction with chloral: pp-Dichloro-diphenyl-trichloroethane formed upon heating Chlorobenzene with chloral in the presence of concentrated sulfuric acid. It is also called D.D.T..

It is a strong and major disinfectant. for more detail click here

What is chlorobenzene used for?

It is used in the manufacture of aniline, phenole, chloronitrobenzene, and disinfectant DDT.

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