Benzoic acid is a carboxylic acid derived from benzene, and it plays a significant role in organic chemistry. Its aromatic ring imparts unique reactivity, and various reactions highlight its versatile nature. Here’s a note on some important reactions of benzoic acid:
 1. Aromatic Electrophilic Substitution
Reaction: Benzoic acid can undergo electrophilic aromatic substitution reactions.
Example: Friedel-Crafts acylation involves the acylation of benzene using benzoic acid as a precursor.
 2. Kolbe-Schmitt Reaction
Reaction: This reaction involves the conversion of benzoic acid to salicylic acid, a precursor to aspirin.
Example: Benzoic acid reacts with sodium hydroxide to form sodium benzoate, followed by carbonation to produce salicylic acid.
 3. Decarboxylation
Reaction: Benzoic acid can undergo decarboxylation under specific conditions, producing benzene.
Example: Heating benzoic acid with a strong base or using soda lime (NaOH/CaO) promotes decarboxylation.
 4. Esterification
Reaction: Benzoic acid can react with alcohol to form esters.
Example: Reaction with methanol in the presence of an acid catalyst produces methyl benzoate.
 5. Benzoylation
Reaction: Benzoic acid can be used as a benzoylating agent in various reactions.
Example: Benzoylation of amines to form benzamides or benzoylation of hydroxyl groups in the presence of acid catalysts.
 6. Clemmensen Reduction
Reaction: Benzoic acid can be reduced to benzene by Clemmensen reduction.
Example: Reduction of benzoic acid using amalgamated zinc and hydrochloric acid.
 7. Grignard Reaction
Reaction: Benzoic acid reacts with a Grignard reagent to form a tertiary alcohol.
Example: Reaction with phenylmagnesium bromide (PhMgBr) produces triphenylmethanol.
 8. Hell-Volhard-Zelinsky Reaction
Reaction: Benzoic acid reacts with phosphorus and bromine to introduce a bromine atom at the alpha position.
Example: Formation of α-bromobenzoic acid.
 9. Schmidt Reaction
Reaction: Benzoic acid can undergo Schmidt reaction to form various products.
Example: Reaction with hydrazoic acid (HN₃) yields phenyl azide.
 10. Benzoin Condensation
Reaction: Benzoic acid can participate in benzoin condensation to form benzoin derivatives.
Example: Reaction with an aldehyde in the presence of cyanide ion to produce benzoin.
 11. Diazotization
Reaction: Benzoic acid can be diazotized to form the corresponding diazonium salt.
Example: Diazotization followed by reaction with phenol to produce salol.
 12. Oxidation to Phenol
Reaction: Benzoic acid can be oxidized to phenol using strong oxidizing agents.
Example: Oxidation with potassium permanganate (KMnOâ‚„) or chromic acid (Hâ‚‚CrOâ‚„) yields phenol.
Benzoic acid’s reactivity arises from the combination of its aromatic ring and carboxylic acid functionalities. These reactions showcase the versatility of benzoic acid as a starting material in organic synthesis and its role in preparing various important compounds.
