How to synthesize p-nitrobenzoic acid and m-nitrobenzoic acid starting from benzene?

Mechanism of nitrification reaction: propose a synthetic pathway for synthesis of p-nitrobenzoic acid and m-nitrobenzoic acid if you are starting from benzene.

1 Answer
Apr 25, 2017

Answer:

How about these?

Explanation:

I. The Nitration Mechanism

(a) Formation of nitronium ion

(i) The sulfuric acid protonates the nitric acid.

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(ii) The protonated nitric acid loses a molecule of water to form nitronium ion

(b) Nitration of toluene

(i) Nitronium ion attacks the aromatic ring

Attack occurs at all possible positions to form resonance stabilized carbonation.

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However, the cations formed by ortho and para attack are more stable than those formed by meta attack.

They put the positive charge next to the methyl group, which is electron-donating and adds to the stabilization.

(ii) The hydrogen sulfate ion formed in Step (a) (i) removes a proton from the intermediate, regenerating the aromatic ring and the sulfuric acid catalyst.

II. Synthesis of 4-Nitrobenzoic acid

(a) Friedel-Crafts alkylation of benzene

Benzene to toluene

(b) Nitration of toluene

Toluene to 4-nitrotoluene

(c). Oxidation of the alkyl side-chain

4-Nitrotoluene to 4-nitrobenzoic acid

III. Synthesis of 3-Nitrobenzoic acid

(a) Friedel-Crafts alkylation of benzene

Benzene to toluene

(b) Oxidation of toluene to benzoic acid

Oxidation

(c) Nitration of benzoic acid

Nitration