What is chlorination of benzene?

Benzene reacts with chlorine or bromine in the presence of a catalyst, replacing one of the hydrogen atoms on the ring by a chlorine or bromine atom. The reactions happen at room temperature. The catalyst is either aluminium chloride (or aluminium bromide if you are reacting benzene with bromine) or iron.

What is chlorination reaction?

Chlorination reactions are part of various processes in the chemical industry, to manufacture heavy chemicals, specialty chemicals, pesticides and pharmaceuticals, in inorganic and organic chemistry. They are a valuable tool in organic synthesis.

Which catalyst is preferable during the chlorination of benzene *?

This page guides you through the mechanism for the electrophilic substitution reaction between benzene and chlorine in the presence of an aluminium chloride or an iron catalyst. The reaction involving bromine is exactly the same, except that iron would be the preferred catalyst.

Why is benzene iodination so hard?

For the halogens, the electronegativity and electrophilicity decrease from F to I in the periodic table. Fluorine is most electrophilic, and Iodine is least. Therefore, Fluorination is highly reactive, and Iodination is highly unreactive for electrophilic aromatic substitution reactions.

What is the mechanism of halogenation of benzene?

Halogenation is an example of electrophillic aromatic substitution. In electrophilic aromatic substitutions, a benzene is attacked by an electrophile which results in substition of hydrogens. However, halogens are not electrophillic enough to break the aromaticity of benzenes, which require a catalyst to activate.

What are 3 uses for chlorine?

Chlorine also has a multitude of industrial uses. Including making bulk materials like bleached paper products, plastics such as PVC and the solvents tetrachloromethane, chloroform and dichloromethane. It is also used to make dyes, textiles, medicines, antiseptics, insecticides and paints.

What is chlorination with example?

The chlorination process involves adding chlorine to water, but the chlorinating product does not necessarily have to be pure chlorine. The three most common types of chlorine used in water treatment are: chlorine gas, sodium hypochlorite, and calcium hypochlorite.

Why is benzene attacked by electrophiles?

Benzene and electrophiles Because of the delocalised electrons exposed above and below the plane of the rest of the molecule, benzene is obviously going to be highly attractive to electrophiles – species which seek after electron rich areas in other molecules.

Is halogenation of benzene exothermic?

Dissociation Energies of Halogens and its Effect on Halogenation of Benzenes. Being so exothermic, a reaction of flourine with benzene is explosive!

What is the mechanism of chlorination of benzene?

Mechanism of chlorination of Benzene [4] 1 First step: Chloronium ion formation, chlorine react with the Lewis acid to form a complex which makes the chlorine more electrophile. 2 Second step: Chloronium ion attack on the ring. 3 Third step: Proton transfer regenerates the aromatic character of the ring.

Is the addition reaction between benzene and bromine exothermic?

This reaction is exothermic by -29kcal/mol. An analogous addition reaction between benzene and bromine would be endothermic by +2kcal. The destruction of the aromaticsextet causes this endothermicity. This additionreaction is not observed under normal reaction conditions.

What happens when benzene is exposed to ultraviolet light?

Addition reaction of hot benzene undergo in the presence of ultraviolet light with chlorine or bromine. Chlorine or bromine atom adds on carbon atom and ring delocalization is permanently broken [2]. For example: 1,2,3,4,5,6-hexachlorocyclohexane is produced when bubble chlorine gas through hot benzene exposed to UV light for an hour.

What is the difference between chlorination and sulfonation?

This process involves the reaction between an organic compound and a sulfur-containing acidic compound such as sulfur trioxide (SO 3 ), sulfuric acid (H 2 SO 4) or chlorosulfuric acid. Sulfonation reactions form a C-S bond between one of the carbon atoms of the organic compound and the sulfur atom of the sulfur-containing compound.