Organic Chemistry R&C Flashcards by Soh Zhao Zheng

Alkane —> Alkyl halide

Free Radical Substitution
UV light, (limited X2 gas)

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Alcohol —> Alkenes

Elimination of H2O
1. Al2O3, heat
2. Excess conc. H2SO4, heat

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Alkyl Halide —> Alkenes

Elimination of HX
Ethanolic KOH/NaOH, heat under reflux

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Alkene —> Alkane

Reduction
H2 (g), Ni catalyst, heat

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Alkene —> Alkyl halide

Electrophilic Addition
HX(g), r.t.p.

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Alkene —> Dihaloalkane

Electrophilic Addition
1. Cl2(g) or Br2(l), r.t.p.
2. X2 dissolved in CCl4, r.t.p.

Observation: Reddish-brown/Orange-red Br2 (refer to Data Booklet) decolourises

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Alkene —> Alcohol

Electrophilic Addition
1. H2O (g), H3PO4 catalyst, heat at high pressure
2. Cold, conc H2SO4, heat with H2O

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Alkene —> Diol

Oxidation
Cold, alkaline KMnO4

Observation: Purple KMnO4 turns colourless, brown ppt forms

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Alkene —> Ketone

Oxidation (fragment contains 2 R groups)
Hot, acidified KMnO4

Observation: Purple KMnO4 turns colourless

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Alkene —> Carboxylic acid

Oxidation (fragment contains 1 R groups)
Hot, acidified KMnO4

Observation: Purple KMnO4 turns colourless

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Nitration of benzene

Electrophilic Substitution
conc. HNO3, conc. H2SO4, maintain at 55°C

Temperature changes based on R groups present

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Halogenation of benzene

Electrophilic Substitution
X2, Fe or anhydrous FeX3 or anhydrous AlX3

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Friedel-Crafts alkylation

RCl, anhydrous AlCl3 (or FeCl3)

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Friedel-Crafts acylation

RCOCl, anhydrous AlCl3

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Oxidation of Benzene side chain

acidified KMnO4, heat under reflux
alkaline KMnO4, heat under reflux

Observations: Purple KMnO4 decolourises, white ppt of benzoic acid forms on cooling
CO2 may be produced (more than 1 C side chain)

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Alcohol —> Alkyl halide

Nucleophilic Substitution
1. HX(g), heat
2. conc. HCl, ZnCl2 catalyst, heat under reflux
3. PX3, rtp
4. PCl5, rtp
5. SOCl2, rtp

Alkyl halide —> Alcohol

Nucleophilic Substitution
NaOH (aq) or KOH (aq), heat under reflux

Alkyl halide —> Nitrile

Nucleophilic Substitution
ethanolic NaCN/KCN, heat under reflux

Nitrile —> Amine

Reduction
1. H2(g), Ni catalyst, heat
2. LiAlH4 in dry ether

Nitrile —> Carboxylic acid

Hydrolysis
1. dilute H2SO4, heat under reflux
2. dilute NaOH, heat under reflux

Alkyl halide —> Amine

Nucleophilic Substitution
excess ethanolic NH3, heat in sealed tube

Chemical test for Alkyl halides

Heat alkyl halide with NaOH (aq)
Acidify cooled products with nitric acid to remove excess alkali (otherwise black ppt formed)
Add aqueous silver nitrate

Can distinguish aryl halides from alkyl halides

Aldehyde —> Alcohol

Reduction (to primary alcohol)
1. LiAlH4
2. NaBH4
3. H2, Ni catalyst

Ketone —> Alcohol

Reduction (to secondary alcohol)
1. LiAlH4
2. NaBH4
3. H2, Ni catalyst

Carboxylic acid ---> Alcohol

Reduction (to primary alcohol) LiAlH4

Alcohol ---> Ether

Intermolecular dehydration conc H2SO4, excess alcohol, heat By-product of alcohol ---> alkene synthesis

Alcohol ---> Ester

Condensation 1. Carboxylic acid, few drops of conc H2SO4, heat under reflux 2. Acyl chloride, rtp

Alcohol ---> Aldehyde

Oxidation (primary alcohol) acidified K2Cr2O7, heat with immediate distillation

Alcohol ---> Carboxylic acid

Oxidation (primary alcohol) 1. acidified K2Cr2O7, heat under reflux 2. acidified KMnO4, heat under reflux

Alcohol ---> Ketone

Oxidation (secondary alcohol) 1. acidified K2Cr2O7, heat under reflux 2. acidified KMnO4, heat under reflux

Iodoform Test

Oxidation warm with I2, NaOH (aq) CH3CH(OH)R + 4I2 + 6OH- ---> RCOO- + CHI3 + 5I- + 5H2O CH3COR + 3I2 +4OH- ---> RCOO- + CHI3 + 3I- + 3H2O

Phenol ---> Ester

NaOH (aq), acyl chloride

Chemical test for Phenols

React with neutral FeCl3 violet colouration formed

Aldehyde/Ketone ---> Cyanohydrin

Nucleophilic addition 1. HCN, small amt of NaOH/KOH (aq) 2. HCN, small amt of NaCN/KCN (aq)

Aldehyde/Ketone ---> Imine

Condensation (with -NH2 group) R-NH2, rtp 2,4-DNPH forms yellow/orange ppt Distinguishing test for aldehydes and ketones

Aldehyde ---> Carboxylic acid

Oxidation 1. acidified K2Cr2O7, heat under reflux 2. acidified KMnO4, heat under reflux Distinguishing test for aldehydes from aliphatic ketones colour changes from orange to green/purple to colourless

Chemical test for Aldehydes

Silver mirror test Tollen's reagent, warm silver mirror OR grey/black ppt formed RCHO + 2[Ag(NH3)2]+ + 3OH- ---> RCOO- + 2Ag(s) + 4NH3 + 2H2O

Chemical test for Aliphatic Aldehydes

Fehling's reagent, warm Brick-red ppt formed RCHO + 2Cu2+ + 5OH- ---> RCOO- + Cu2O(s) + 3H2O

Aldehyde/Ketone ---> Alcohol

Reduction 1. LiAlH4, dry ether 2. H2(g), Ni catalyst 3. NaBH4 Aldehydes form primary Ketones form secondary