Alcohols

• Alcohols General formula = $C_nH_{2n+1}$ OH
• Alcohols Functional Group: OH
• Methanol (n=1)

  
• Ethanol (n=2)

  
• Propanol (n=3)

  
• Butanol (n=4)

  
• Fermentation:

  • Enzymes in yeast break down glucose to ethanol and carbon dioxide, giving out heat
  • Can be done with substances that contain cellulose, starch or glucose
  • Done by grinding source (e.g. grapes) and adding enzymes to break down cellulose and starch into glucose.
  • Leave to ferment
  • Fractional distillation used to get ethanol from the mixture
• Catalytic Addition of Steam to Ethene:

  • Ethene is obtained by cracking long-chain alkenes from oil.
  • The ethene reacts with steam (reversibly) in the following conditions:
  • 570 °C
  • 60 - 70 atm
  • Catalyst = phosphoric acid
  • Low temperature gives a better yield, but high temperature is used to give a better rate of reaction.
• Alcohol evaporates easily, so used as solvent in glues, printing inks & perfumes