Reactions of benzenediazonium chloride (map)बेन्ज़ीनडाइऐज़ोनियम क्लोराइड की अभिक्रियाएँ (मानचित्र)Reactions of benzenediazonium chloride (map)

Class 12 Chemistry · Chapter 9 · interactive diagram

Parts and what they mean

• Benzenediazonium chloride (बेन्ज़ीनडाइऐज़ोनियम क्लोराइड) — –N₂⁺ is a very good leaving group: it escapes as N₂ gas, letting other groups enter the ring (A); or the –N=N– is kept (B, coupling).
• Sandmeyer: Cu₂Cl₂/HCl → chlorobenzene (सैन्डमायर: Cu₂Cl₂/HCl → क्लोरोबेन्ज़ीन) — ArN₂⁺X⁻ → (Cu₂Cl₂/HCl) → ArCl + N₂. Cl⁻, Br⁻, CN⁻ are introduced in the presence of Cu(I).
• Sandmeyer: Cu₂Br₂/HBr → bromobenzene (सैन्डमायर: Cu₂Br₂/HBr → ब्रोमोबेन्ज़ीन) — ArN₂⁺X⁻ → ArBr + N₂.
• Sandmeyer: CuCN/KCN → cyanobenzene (सैन्डमायर: CuCN/KCN → सायनोबेन्ज़ीन) — ArN₂⁺X⁻ → ArCN + N₂. CN cannot be put on chlorobenzene by nucleophilic substitution, but is easy via the diazonium salt.
• Gatterman: Cu powder + HCl (गाटरमान: Cu चूर्ण + HCl) — ArN₂⁺X⁻ + Cu/HCl → ArCl + N₂ + CuX. The yield of the Sandmeyer reaction is better than that of the Gatterman reaction.
• Gatterman: Cu powder + HBr (गाटरमान: Cu चूर्ण + HBr) — ArN₂⁺X⁻ + Cu/HBr → ArBr + N₂ + CuX.
• KI → iodobenzene (KI → आयोडोबेन्ज़ीन) — Iodine is not easily introduced into the ring directly; with KI: ArN₂⁺Cl⁻ + KI → ArI + KCl + N₂.
• HBF₄, then heat → fluorobenzene (HBF₄, फिर गर्म → फ़्लुओरोबेन्ज़ीन) — ArN₂⁺Cl⁻ + HBF₄ → ArN₂⁺BF₄⁻ (precipitate) + HCl; heating gives ArF + BF₃ + N₂.
• Hypophosphorous (phosphinic) acid → benzene (हाइपोफ़ॉस्फ़ोरस (फ़ॉस्फ़िनिक) अम्ल → बेन्ज़ीन) — Mild reducing agent: ArN₂⁺Cl⁻ + H₃PO₂ + H₂O → ArH + N₂ + H₃PO₃ + HCl (it is oxidised to phosphorous acid).
• Ethanol → benzene (एथेनॉल → बेन्ज़ीन) — ArN₂⁺Cl⁻ + CH₃CH₂OH → ArH + N₂ + CH₃CHO + HCl (ethanol is oxidised to ethanal).
• Warm water (≈283 K) → phenol (गर्म जल (≈283 K) → फ़ीनॉल) — If the temperature rises up to 283 K the salt is hydrolysed: ArN₂⁺Cl⁻ + H₂O → ArOH + N₂ + HCl.
• NaNO₂ + Cu, heat → nitrobenzene (NaNO₂ + Cu, गर्म → नाइट्रोबेन्ज़ीन) — Diazonium FLUOROBORATE heated with aqueous NaNO₂ in the presence of copper: ArN₂⁺BF₄⁻ + NaNO₂ → ArNO₂ + NaBF₄ + N₂.
• Coupling with phenol or aniline → azo dyes (फ़ीनॉल या ऐनिलीन से युग्मन → ऐज़ो रंजक) — Reaction with retention of the diazo group: the –N=N– joins two aromatic rings (electrophilic substitution at the para position).
• Two classes of reactions (अभिक्रियाओं के दो वर्ग) — (A) displacement of nitrogen, (B) retention of the diazo group.

Original diagram drawn by Simple Learning Hub, based on the NCERT textbook. Report a mistake