Benzoic acid, like other carboxylic acids, undergoes several important reactions.
These reactions are primarily due to the reactivity of the carboxyl group (-COOH).
1.Formation of Benzoate Salts:
Reaction: Benzoic acid reacts with bases (e.g., NaOH) to form benzoate salts.
Example: C6H5COOH+NaOH→C6H5COONa+H2O
2. Esterification of Benzoic Acid/ Aromatic Acids:
Reaction: Benzoic acid reacts with alcohols in the presence of an acid catalyst (e.g., H₂SO₄) to form esters.
Example: C6H5COOH+CH3OH→C6H5COOCH3+H2O
3. Decarboxylation:
Reaction: Benzoic acid can lose a CO₂ molecule upon heating, especially in the presence of soda lime (NaOH and CaO), resulting in benzene.
Example: C6H5COOH→NaOH,CaOC6H6+CO2
4.Reduction to Benzyl Alcohol:
Reaction: Benzoic acid can be reduced to benzyl alcohol using reducing agents like LiAlH₄.
Example: C6H5COOH→LiAlH4C6H5CH2OH
5. Halogenation (Electrophilic Aromatic Substitution):
Reaction: The aromatic ring of benzoic acid can undergo electrophilic aromatic substitution reactions, like halogenation, nitration, and sulfonation, typically at the meta position relative to the carboxyl group due to the deactivating effect of the -COOH group.
Example: Nitration of benzoic acid produces m-nitrobenzoic acid.
6. Nitration:
Reaction: Benzoic acid reacts with a mixture of concentrated HNO₃ and H₂SO₄ to yield m-nitrobenzoic acid.
Example: C6H5COOH→HNO3/H2SO4m-NO2C6H4COOH
These reactions highlight the versatility of benzoic acid in synthetic chemistry, allowing for the creation of a wide variety of functionalized aromatic compounds.