alcohols

• contain the functional group -OH
• • Ethanol undergoes oxidation in three different ways

  1. Complete combustion

  • Burning in air or oxygen

  ethanol + O2 → CO2 + H2O

  2. Microbial oxidation

  ethanol + oxygen in the air → ethanoic acid

  3. Ethanol and potassium dichromate(VI)

  • With heat
  • With dilute sulfuric acid

  ethanol + potassium dichromate(VI) → ethanoic acid
• Manufacture of Ethanol

  1. Ethene + steam

  • Catalyst: phosphoric acidTemperature: 300oCPressure: 60-70 atm
• 2. Fermentation of glucose

  • Absence of air (anaerobic)
  • Optimum temperature of about 30oC
  • Using the enzymes in yeast
• Fermentation of Glucose

  glucose → ethanol + carbon dioxide

  • Why is the optimum temperature around 25 to 50oC?
  • If too low: yeast that is used would be inactive
  • If too high: enzymes in yeast would be denatured / would no longer function
  • Why must air be kept out (absence of oxygen)?
  • If there is air: ethanol would be oxidised to ethanoic acid