Organic Synthesis

• Alcoholic NH3


  Heated under pressure
• NuSub


  1. Step 1 H2SO4

  2. EAdd

  3. Step 2 H2O warm

  4. hydrolysis

  5. KOH aqueous

  6. heat under reflux

  7. NuSub
• Fr Sub


  1. Br2, Cl2

  2. UV light

  3. KOH aqueous

  4. heat under reflux

  5. Nu Sub
• Organic compounds


  • 1o amine
  • alkane
  • halogenoalkane
  • alkene
  • alcohol
  • ketone
  • aldehyde
  • carboxylic acid
  • diol
  • dihalogenoalkane
• EAdd


  1. Br2, Cl2 room temp

  2. HBr, HCl room temp
• Elimination


  1. KOH alcoholic

  2. heat under reflux

  3. conc. H2SO4 or

  4. conc. H3PO4
• Partial oxidation


  1. If primary

  2. Na2Cr2O7/H+

  3. heat and distill
• Oxidation


  1. If secondary

  2. Na2Cr2O7/H+

  3. heat
• Oxidation


  1. If primary

  2. Na2Cr2O7/H+

  3. heat under reflux + excess

  4. oxidising agent
• NuSub


  1. KCN in ethanol/

  2. water mixture heat

  3. under reflux
• Polymerisation


  1. poly(alkene)

  2. high pressure

  3. catalyst
• Esterification


  1. Acyl chloride/

  2. acid anhydride

  3. Alcohol + H2SO4

  4. heat

  5. Carboxylic acid +

  6. H2SO4

  7. heat
• Nu add/elim


  1. H2O room temp

  2. NH3 room temp

  3. 1o amine

  4. room temp

  5. Acyl chloride

  6. room temp
• Reduction


  1. NaBH4

  2. LiAlH4 in ether
• Nu Add


  NaCN + H2SO4
• Amines


  • 2o amine
  • 3o amine
  • Quaternary salt
• NuSub


  halogenoalkane
• Esters and amides can be hydrolysed by NaOH and acids
• Chemists aim to design processes that do not require a solvent and that use non-hazardous starting materials
• Chemists aim to design production methods with fewer steps that have a high percentage atom economy
• Distillation


  Separation technique to separate an organic product from its reacting mixture
• Oxidation of primary alcohol

  1. Reaction: primary alcohol aldehyde

  2. Reagent: potassium dichromate (VI) solution and dilute sulfuric acid

  3. Conditions: use a limited amount of dichromate and warm gently and distil out the aldehyde as it forms
• Oxidation of primary alcohol

  1. Reaction: primary alcohol carboxylic acid

  2. Reagent: potassium dichromate(VI) solution and dilute sulfuric acid

  3. Conditions: use an excess of dichromate, and heat under reflux
• Reflux


  Used when heating organic reaction mixtures for long periods, condenser prevents organic vapours from escaping
• Never seal the end of the condenser as the build up of gas pressure could cause the apparatus to explode
• Anti-bumping granules


  Added to the flask in both distillation and reflux to prevent vigorous, uneven boiling
• Electric heaters are often used to heat organic chemicals as they are normally highly flammable
• Fractional distillation


  Used to separate liquids with different boiling points
• Fractional distillation


  1. Heat the flask

  2. Vapours pass up the fractionating column

  3. Vapour of substance with lower boiling point reaches top first

  4. Vapours with higher boiling points condense back into the flask

  5. Only most volatile vapour passes into the condenser

  6. Condenser cools vapours and condenses to liquid
• Measuring boiling point


  Can determine purity of liquid, but not most accurate method of identification
• Recrystallisation


  1. Dissolve impure compound in minimum volume of hot solvent

  2. Hot filter solution

  3. Cool filtered solution in ice

  4. Suction filtrate to separate crystals

  5. Wash crystals with distilled water

  6. Dry crystals between absorbent paper
• Drying agent


  Insoluble in organic liquid, does not react with organic liquid
• Purifying organic liquid


  1. Put distillate in separating funnel

  2. Wash with sodium hydrogencarbonate or saturated sodium chloride solution

  3. Add drying agent

  4. Decant liquid into distillation flask

  5. Distil to collect pure product
• Melting point


  Indicates degree of purity, sharp melting point indicates high purity
• Impurities lower melting point and cause melting over a range
• Functional group tests


  • Alkene - bromine water
  • Aldehyde - Fehling's solution, Tollen's reagent
  • Carboxylic acid - sodium carbonate
  • 1o 2o alcohol and aldehyde - sodium dichromate and sulfuric acid
  • Chloroalkane - warm with silver nitrate
  • Acyl chloride - silver nitrate
• Tollen's reagent


  Oxidises aldehydes to carboxylic acids, forms silver mirror
• Fehling's solution


  Oxidises aldehydes to carboxylic acids, forms red copper(I) oxide precipitate