alcohols.

• hydration reaction- ethene to ethanol

  • reagent used is phosphoric acid or sulphuric acid

  the conditions needed;

  • excess ethene / steam
  • 60 atm
• nucleophilic substitution- bromethane to ethanol

  • reagent used is potassium / sodium hydroxide
  • conditions; warm / heat / reflux and aqueous

  reasons why method is not used in the industry;

  • bromoethane has to be made
  • bromoethane is expensive
  • the rate of reaction is slow
  • low yield
• Fermentation;

  • C6H12O6 —-> 2CH3CH2OH + 2CO2
  • conditions; 37 °C, yeast, anaerobic
• Fermentation may not be a carbon-neutral process because transporting sugar burns fossil fuels which releases co2
• carbon-neutral means there is no net emission of co2 into the atmosphere
• fractional distillation produces a more concentrated solution of ethanol than fermentation
• advantages of using ethanol as a fuel instead of a petroleum column;

  • ethanol doesn’t contain sulphur-containing impurities
  • ethanol produces less pollution
  • ethanol is less smokey
  • less carbon / carbon monoxide is produced
• Advantages of fermentation over hydration;

  • low technology is required
  • renewable feedstock
  • can be used in drinks / perfumes
  • considered to be green
• disadvantages of fermentation over hydration;

  • reaction is slow
  • low yield
  • intensive labour
  • has to be distilled
• the catalyst used in the elimination reaction of ethane to ethene is concentrated sulphuric acid
• an alcohol is tertiary if there are no hydrogens on the central carbon
• advantages of hydration over fermentation;

  • reaction is fast
  • pure product
  • 100% alcohol
  • continuous process
  • cheap on manpower
  • high yield
• disadvantages of hydration over fermentation;

  • high technology is required
  • ethene is not renewable
  • equipment is expensive
• saturated means it contains single bonds only
• hydrogenation reaction of alkene to alkane;

  • catalysts; nickel, platinum, palladium
  • the reagent is hydrogen
• test for alkenes;

  • reagent is bromine water
  • if alkene present, it goes from orange to colourless
• conditions needed for complete combustion of fuel in air;

  • good supply of air
  • good mixing of fuel and air
• disadvantages of using crops for ethanol production;

  • reaction is slow
  • depletes food supply
  • uses fossil fuels
  • not carbon-neutral
• conditions for hydration of ethene to ethanol for highest yield;

  • excess ethene or steam
  • 60 atm
  • 400 °C
• catalyst for ethanol to ethene is phosphoric / sulfuric acid
• when unsaturated molecules are hardened, a hydrogenation reaction is taking place, in which the reagent is hydrogen and catalyst is nickel
• elimination reaction of alcohol;

  • small molecule of h2o is lost
  • -OH group and an adjacent hydrogen is lost
  • catalyst used is aluminum oxide
  • conditions; 600K
  • alcohol —-> alkene + h2o
• uses of ethene

  • ripening fruit
  • making polymers
  • making plastics
• why is thermal cracking reactions are used in the industry?

  • to make products which are greater in demand
  • to make alkenes
• what is the process in which SO2 is removed?

  flue gas desulfurisation
• why might two hydrocarbons have similar boiling points?

  similar sizes, so similar van der waals’ forces between molecules
• differentiate primary and secondary alcohols to tertiary

  • use acidified K2Cr2O7
• distinguish between 1° and 2° alcohols

  • identify the aldehyde
  • use tollen’s reagant