Named Reactions | NEET Chemistry | Complete List with Mechanisms

🧪 Aldehydes & Ketones Carbonyl Compounds

Aldol Condensation Addition

2 RCHO → RCH(OH)CHRCHO

Two aldehydes/ketones with α-hydrogen combine in presence of dilute base to form β-hydroxy carbonyl compound.

Reagent: Dilute NaOH / KOH Condition: Cold Mechanism: Enolate formation Product: β-hydroxy aldehyde/ketone

Example: 2 CH₃CHO → CH₃CH(OH)CH₂CHO (3-hydroxybutanal)

Cannizzaro Reaction Disproportionation

2 RCHO (no α-H) → RCH₂OH + RCOOK

Aldehydes without α-hydrogen undergo self-oxidation and reduction with concentrated alkali.

Reagent: Conc. NaOH / KOH Condition: Heat Mechanism: Hydride transfer Products: Alcohol + Salt

Example: 2 HCHO + NaOH → CH₃OH + HCOONa (Formaldehyde)

Clemmensen Reduction Reduction

R-CO-R' → R-CH₂-R'

Carbonyl group reduced to methylene group using zinc amalgam and hydrochloric acid.

Reagent: Zn(Hg) + HCl Condition: Reflux Mechanism: Radical Product: Alkane

Example: C₆H₅COCH₃ → C₆H₅CH₂CH₃ (Ethylbenzene)

Wolff-Kishner Reduction Reduction

R-CO-R' → R-CH₂-R'

Carbonyl group reduced to methylene using hydrazine and strong base.

Reagent: NH₂NH₂ + KOH Condition: Heat in ethylene glycol Mechanism: Hydrazone formation Product: Alkane

Example: C₆H₅COCH₃ → C₆H₅CH₂CH₃ (Ethylbenzene)

🔄 Aromatic Chemistry Benzene & Derivatives

Friedel-Crafts Alkylation Electrophilic Substitution

ArH + RCl → ArR + HCl

Introduction of alkyl group into aromatic ring using alkyl halide and Lewis acid catalyst.

Reagent: RCl + Anhydrous AlCl₃ Condition: Dry conditions Mechanism: Electrophilic substitution Product: Alkyl benzene

Example: C₆H₆ + CH₃Cl → C₆H₅CH₃ + HCl (Toluene)

Friedel-Crafts Acylation Electrophilic Substitution

ArH + RCOCl → ArCOR + HCl

Introduction of acyl group into aromatic ring using acyl chloride and Lewis acid catalyst.

Reagent: RCOCl + Anhydrous AlCl₃ Condition: Dry conditions Mechanism: Electrophilic substitution Product: Aromatic ketone

Example: C₆H₆ + CH₃COCl → C₆H₅COCH₃ + HCl (Acetophenone)

Sandmeyer Reaction Diazonium

ArN₂⁺Cl⁻ + CuCl/HCl → ArCl + N₂

Conversion of diazonium salt to halobenzene using copper(I) halide.

Reagent: CuCl/HCl or CuBr/HBr Condition: Room temp Mechanism: Radical Product: Halobenzene

Example: C₆H₅N₂⁺Cl⁻ → C₆H₅Cl + N₂ (Chlorobenzene)

Gattermann Reaction Diazonium

ArN₂⁺Cl⁻ + Cu/HCl → ArCl + N₂

Similar to Sandmeyer but uses copper powder instead of copper(I) halide.

Reagent: Cu + HCl Condition: Room temp Mechanism: Radical Product: Halobenzene

Example: C₆H₅N₂⁺Cl⁻ → C₆H₅Cl + N₂ (Chlorobenzene)

Schiemann Reaction Diazonium

ArN₂⁺BF₄⁻ → ArF + BF₃ + N₂

Conversion of diazonium salt to fluorobenzene using fluoroborate.

Reagent: HBF₄ Condition: Heat Mechanism: Radical Product: Fluorobenzene

Example: C₆H₅N₂⁺BF₄⁻ → C₆H₅F + BF₃ + N₂ (Fluorobenzene)

Diazotization Amines

ArNH₂ + NaNO₂ + 2HCl → ArN₂⁺Cl⁻ + NaCl + 2H₂O

Primary aromatic amines convert to diazonium salts at low temperature.

Reagent: NaNO₂ + HCl Condition: 0-5°C Mechanism: Diazotization Product: Diazonium salt

Example: C₆H₅NH₂ → C₆H₅N₂⁺Cl⁻ (Benzenediazonium chloride)

Coupling Reaction Diazonium

ArN₂⁺ + Ar'H → Ar-N=N-Ar'

Diazonium salt couples with phenols or aromatic amines to form azo compounds.

Reagent: Phenol/Aniline Condition: Basic medium Mechanism: Electrophilic substitution Product: Azo dye

Example: C₆H₅N₂⁺ + C₆H₅OH → C₆H₅-N=N-C₆H₄OH (p-hydroxyazobenzene)

⚡ Alkanes & Alkyl Halides Hydrocarbons

Wurtz Reaction Coupling

2R-X + 2Na → R-R + 2NaX

Alkyl halides react with sodium metal in dry ether to form higher alkanes.

Reagent: Na + Dry ether Condition: Room temp Mechanism: Radical Product: Alkane

Example: 2 CH₃Br + 2Na → CH₃CH₃ + 2NaBr (Ethane)

Finkelstein Reaction Halogen Exchange

R-Cl + NaI → R-I + NaCl

Chloro or bromo alkanes react with sodium iodide in acetone to form iodoalkanes.

Reagent: NaI + Acetone Condition: Reflux Mechanism: SN₂ Product: Iodoalkane

Example: CH₃Cl + NaI → CH₃I + NaCl (Iodomethane)

Swarts Reaction Halogen Exchange

R-Cl + AgF → R-F + AgCl

Chloro or bromo alkanes react with silver fluoride to form fluoroalkanes.

Reagent: AgF Condition: Room temp Mechanism: SN₂ Product: Fluoroalkane

Example: CH₃Cl + AgF → CH₃F + AgCl (Fluoromethane)

🧪 Carboxylic Acids & Derivatives Acid Derivatives

Hell-Volhard-Zelinsky (HVZ) Reaction Halogenation

R-CH₂COOH + Br₂ → R-CH(Br)COOH + HBr

Carboxylic acids with α-hydrogen are halogenated at the α-position using halogens and red phosphorus.

Reagent: Br₂ + P Condition: Heat Mechanism: Free radical Product: α-halo acid

Example: CH₃COOH + Br₂ → BrCH₂COOH (Bromoacetic acid)

🧪 Alcohols & Phenols Hydroxy Compounds

Reimer-Tiemann Reaction Formylation

Phenol + CHCl₃ + NaOH → Salicylaldehyde

Phenols react with chloroform and NaOH to form ortho-hydroxy benzaldehydes.

Reagent: CHCl₃ + NaOH Condition: Heat Mechanism: Carbene Product: Salicylaldehyde

Example: C₆H₅OH → C₆H₄(OH)CHO (o-hydroxybenzaldehyde)

Kolbe's Reaction Carboxylation

Phenol + CO₂ + NaOH → Salicylic acid

Phenols react with carbon dioxide in presence of base to form salicylic acid.

Reagent: CO₂ + NaOH Condition: High pressure, heat Mechanism: Electrophilic substitution Product: Salicylic acid

Example: C₆H₅OH + CO₂ → C₆H₄(OH)COOH (Salicylic acid)

🔬 Grignard Reagents Organometallic

Grignard Reagent Formation Organometallic

R-X + Mg → R-Mg-X

Alkyl/aryl halides react with magnesium metal in dry ether to form Grignard reagents.

Reagent: Mg + Dry ether Condition: Dry, inert atmosphere Mechanism: Oxidative addition Product: Grignard reagent

Example: CH₃Br + Mg → CH₃MgBr (Methyl magnesium bromide)

Grignard with Carbonyl Nucleophilic Addition

R-MgX + R'CHO → R'CH(OH)-R

Grignard reagents add to aldehydes to form secondary alcohols.

Reagent: RMgX + Aldehyde Condition: Dry ether, then H₃O⁺ Mechanism: Nucleophilic addition Product: Secondary alcohol

Example: CH₃MgBr + HCHO → CH₃CH₂OH (Ethanol)

🧬 Polymerization Polymers

Ziegler-Natta Polymerization Polymerization

n CH₂=CH₂ → (CH₂-CH₂)n

Ethylene polymerizes to polyethylene using Ziegler-Natta catalyst (TiCl₄ + AlEt₃).

Reagent: TiCl₄ + AlEt₃ Condition: Medium pressure Mechanism: Coordination Product: Polyethylene

Example: n CH₂=CH₂ → (CH₂-CH₂)n (Polyethylene)

Diels-Alder Reaction Cycloaddition

Diene + Dienophile → Cyclohexene

Conjugated diene reacts with dienophile to form six-membered ring.

Reagent: Heat Condition: Heat Mechanism: Pericyclic Product: Cyclohexene derivative

Example: Butadiene + Ethene → Cyclohexene