alcohols

• alcohols contain the functional group -OH
• uses of alcohol:

  • fuels (cars)
  • solvents (perfume)
  • drinks (ethanol)
• first 4 members of a homologous series of alcohols:

  • methanol - CH3OH
  • ethanol - C2H5OH
  • propanol - C3H7OH
  • butanol - C4H9OH
• ethanol can be made by hydrating ethene, which requires 300 temp, 70 atm pressure and phosophoric acid catalyse

  adv = high yield of ethanol

  disadv = high temp and energy, comes from crude oil = unrenewable
• fermentation of sugar:

  glucose ---> ethanol and carbon dioxide

  aqueous solutions of ethanol are produced when sugar solutions are fermented using yeast

  conditions = temp 30 and anaerobic conditions (no oxygen)
• fermentation of sugar

  adv = doesn't require a lot of energy as low temp, sugar comes from plants so renewable

  disadv = product is an aqueous solution, which would have to be purified via distillation which requires energy
• solubility in water:

  • alcohols are soluble in water and form neutral solutions
  • as the number of carbon atoms increases, the solubility decreases
• reaction with sodium:

  ethanol + sodium --> sodium ETHoxide + hydrogen

  will react steadily giving off bubbles of hydrogen gas and leaving a colourless solution
• reacting with oxidising agent:

  ethanol + oxygen atoms from oxidising agent ---> ETHanoic acid + water

  • ethanol has been oxidised to ethanoic acid (a carboxylic acid)
• combustion of alcohols:

  alcohol + oxygen --> carbon dioxide + water

  alcohols are flammable

  used in spirit burners and as biofuels