Carbonyl compounds

• Aldehyde can be reduced to primary alcohol by:

  • LiAlH4 in dry ether, rtp
  • NaBH4, ethanol, rtp
  • hydrogen gas, Ni/Pt/Pd catalyst, heat
• Ketones can be reduced to secondary alcohols by:

  • LiAlH4 in dry ether, rtp
  • NaBH4, ethanol, rtp
  • hydrogen gas, Ni/Pt/Pd catalyst, heat
• Nucleophilic addition to form nitriles from aldehydes/ketones

  • HCN, trace amount of NaCN/NaOH, cold
  • NaCN/NaOH added to increase concentration of CN- ions
  • NaCN can ionise completely
  • OH- can react with HCN to give CN-
• 2,4-DNPH can test for both aldehyde and ketone, orange ppt will be formed
• Tollens’ reagent and heat can be used to test for aromatic and aliphatic aldehydes
• fehling’s solution and heat tests for aliphatic aldehyde, brick-red ppt
• I2 in NaOH (aq) and heat used to test for this group

  
• acid hydrolysis of nitriles form Carboxylic acids and amines (ammonium ion)

  • using H2SO4 (aq), heat
• Alkaline hydrolysis of nitriles form carboxylate salt and ammonia

  • NaOH (aq), heat
• aldehydes can undergo oxidation with KMnO4 (aq) and H2SO4(aq) with heating to form carboxylic acid