lec 4 reactions

🔥⚗️ 3 HC≡CH ──Red hot Fe tube · 873K──▶ C₆H₆ · three acetylene molecules cyclically trimerize

Cyclic polymerization of ethyne → Benzene

🧪🧂 C₆H₅COONa + NaOH ──CaO · △──▶ C₆H₆ + Na₂CO₃ · soda lime = NaOH + CaO

Decarboxylation of sodium benzoate → Benzene

🌸⚗️ C₆H₅OH + Zn ──△──▶ C₆H₆ + ZnO · phenol vapours over heated zinc dust

Reduction of phenol (zinc dust) → Benzene

⚡🔄 C₆H₅–H + E⁺ ──Lewis acid──▶ C₆H₅–E + H⁺ · benzene + electrophile → substituted benzene

General EAS mechanism

💛💥 C₆H₆ + conc.HNO₃ + conc.H₂SO₄ ──323–333K──▶ C₆H₅NO₂ + H₂O

Nitration of benzene → Nitrobenzene

🟢⚗️ C₆H₆ + Cl₂ ──anhyd. AlCl₃ · room temp──▶ C₆H₅Cl + HCl

Chlorination of benzene → Chlorobenzene

🟤⚗️ C₆H₆ + Br₂ ──Fe or FeBr₃ · room temp──▶ C₆H₅Br + HBr

Bromination of benzene → Bromobenzene

🌋🧪 C₆H₆ + H₂SO₄(SO₃) ──△──▶ C₆H₅SO₃H + H₂O · fuming sulphuric acid

Sulfonation of benzene → Benzenesulphonic acid

🔧🧲 C₆H₆ + CH₃Cl ──anhyd. AlCl₃──▶ C₆H₅CH₃ + HCl

Friedel-Crafts alkylation → Toluene (methylation)

🔧⚙️ C₆H₆ + C₂H₅Cl ──anhyd. AlCl₃──▶ C₆H₅C₂H₅ + HCl

Friedel-Crafts alkylation → Ethylbenzene (ethylation)

🔧✨ C₆H₆ + CH₃COCl ──anhyd. AlCl₃ · △──▶ C₆H₅COCH₃ + HCl · using acetyl chloride

Friedel-Crafts acylation → Acetophenone (acetyl chloride)

🔧🍶 C₆H₆ + (CH₃CO)₂O ──anhyd. AlCl₃ · △──▶ C₆H₅COCH₃ + CH₃COOH · using acetic anhydride

Friedel-Crafts acylation → Acetophenone (acetic anhydride)

💨🔩 C₆H₆ + 3H₂ ──Ni · 300°C · 30 atm──▶ C₆H₁₂ · addition reaction NOT substitution

Hydrogenation of benzene → Cyclohexane