Carboxylic acids and derivatives

• Esters are carboxylic acid + alcohol

  Conditions required

  • An acid catalyst usually H2SO4
  • Heat
• Acid catalysed hydrolysis

  Ester + Water in acidic conditions would cause equilibrium to shift to the left which means low yield of alcohol and carboxylic acid

  
• Base catalysed hydrolysis

  Where sodium hydroxide NaOH is reacted with the ester and water to make a carboxylate salt and cause equilibrium to shift to right to increase yield of alcohol made

  
• Carboxylate salt naming e.g. CH3CH2COONA would be called sodium propanoate
• Glycerol + 3 Fatty acids = Tri-ester which would be used to make vegetable oil and fats
• Glycerol is an alcohol so it's IUPAC naming would be propane-1,2,3-triol
• Acid hydrolysis of triesters

  Triesters + 3H2O in acidic conditions would react to form glycerol and 3 fatty acids
• Base hydrolysis of a triester

  Triester + 3H2O with 3NaOH would react to form glycerol and soap

  
• In soap, the polar end ( the Na+O- bit) would interact with water while the non polar tail interacts with the grease or fat on dirty plates then the water washes it off
• Methanol + Fatty acids react to form Biodiesel and water
• Uses of esters

  • Soap
  • Biodiesel
  • Solvents for reaction
  • Plasticisers ( something added to plastics to make it malleable which means flexible)
  • Perfumes
  • Flavourings
• Acylation

  The acyl group formula is RCO-x ( R-C=O)

  x can be an OR which would form an ester , Cl which would form acid chlorides and OCOR which forms acid anhydrides
• Nucleophilic addition elimination in acid chlorides

  Three substances go through nucleophilic addition elimination with acid chloride

  • Water which forms a carboxylic acid and hydrogen chloride
  • Alcohol ( forms an ester and hydrogen chloride)
  • Ammonia (forms an amide and hydrogen chloride e.g. ethanamide )
• Nucleophilic addition elimination

  Amides would react with any of the carboxylic derivatives e.g. esters, acid chlorides and acid anhydrides would form N-substituded amides

  
• In industries acid anhydrides are preferred to acid chlorides because

  • It's safer ( HCl is a toxic gas)
  • Carboxylic acids form which can be used so 100% atom economy
  • It's cheaper
• Preparation of aspirin

  Salicylic acid + either ethanoic anhydride and ethanol chloride would form aspirin