3) Describe any two methods of preparation of
benzene? Explain the halogenation, alkylation,
acylation, nitration and sulphonation of benzene.
Answers
Answer: See explanation
Explanation:
Presentation of benzene:
(1) Ring presentation
(2) Bond Presentation
(A) halogenation of Benzene
Halogenation is an example of electrophilic aromatic substitution. In electrophilic aromatic substitutions, a benzene is attacked by an electrophilic which results in substition of hydrogens.
(B) Alkylation of Benzene
Alkylation means substituting an alkyl group into benzene ring.
(C) Acylation of Benzene
An acyl group is an alkyl group attached to a carbon-oxygen double bond. If "R" represents any alkyl group, then an acyl group has the formula RCO-. Acylation means substituting an acyl group into benzene ring.
(D) Sulphonation of Benzene
Sulph onation is a reversible reaction that produces benzene sulfonic acid by adding sulfur tri oxide and fuming sulfuric acid. The reaction is reversed by adding hot aqueous acid to benzenesulfonic acid to produce benzene.