Products from oil

• Ceramics, polymers and composites


  Most of the glass we use is soda-lime glass, made by heating a mixture of sand, sodium carbonate and limestone.

  Borosilicate glass, made from sand and boron trioxide, melts at higher temperatures than soda-lime glass.

  Clay ceramics, including pottery and bricks, are made by shaping wet clay and then heating in a furnace.

  The properties of polymers depend on what monomers they are made from and the conditions under which they are made.

  For example, low density (LD) and high density (HD) poly(ethene) are produced from ethene.
• Ceramics, polymers and composites


  Thermosoftening polymers melt when heated. Thermosetting polymers do not melt when they are heated. Students should be able to: • explain how low density and high density poly(ethene) are both produced from ethene

  • explain the difference between thermosoftening and thermosetting polymers in terms of their structures.

  Most composites are made of two materials, a matrix or binder surrounding and binding together fibres or fragments of the other material, which is called the reinforcement.

  Students should be able to recall some examples of composites.
• Cracking for hydrocarbons

  Many of the fractions obtained from fractional distillation aren't very useful. Those that contain long chain molecules are thick solids / liquids with high boiling points that don't burn easily, which makes them particularly useless as the main demand from crude oil is fuels which are small chain molecules
• Catalytic Cracking


  When long chain molecules are vaporised and passed over a hot catalyst - thermal decomposition occurs , breaking them down

  
• Steam cracking


  Carried out by vaporising a hydrocarbon and mixing it with steam at a very high temperature

  Cracking can form both an alkane and alkene

  Alkenes have double bonds between 2 of their carbon atoms - they are unsaturated

  Can have more than one alkane / alkene

  CnH2n

  First 4 - ethene, propene, butene, pentene
• Alkenes

  Diagram

  
• Bromine water and alkenes


  If you add bromine water to a solution of an alkane, the bromine water stays the same

  But if you add it to a solution of an alkene - the water becomes colourless because alkenes are more reactive than alkanes hence the colour change in the alkene

  Addition reaction - things make one

  Ethene + Bromine - Dibromoethane
• Bromine and alkenes 


  Diagram

  
• Hydration

  Ethanol (and other alcohol) can be made from the hydration(addition of water) of ethane (more alkenes)

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

  Ethene + water - ethanol

  
• Hydrogenation

  Alkenes are unsaturated meaning we can add more hydrogen to make them saturated

  Uses a nickel catalyst and usually at a temperature of 60 degrees

  Ethene + hydrogen - ethane
• Addition polymerisation


  Plastics are polymers made from monomers - by using different monomers, you can make different polymers with various properties

  Ethene - polyethene

  Propene - polypropene
• Ethene C2H4


  Smallest unsaturated hydrocarbon - used to make the polymer polythene which is a really useful plastic as it is strong and easy to shape. It is transparent, except when adding colouring to it.

  Carrier bags, cling films and dustbins are some polythene examples
• Propene C3H6


  Makes polymer polypropene which forms a very strong and tough plastic - used for carpets, milk crates and ropes.
• Addition polymerisation 


  Diagram

  
• How do monomers join together

  When alkene molecules join together, the double covalent bond between the 2 carbons 'opens up' and is replaced by a single covalent bond between the 2 carbon .

  They polymer chains they form are made up of a backbone of thousands of carbon atoms

  This is addition polymerisation - forms an addition polymer

  The long chain molecules are made up of repeated patterns of atoms - the repeating unit has the same displayed formula of one of its monomers, but the double bond - single one with a single bond sticking out on each end
• How do monomers join together

  Only one product is formed, just like other addition reactions of alkenes

  
• Types of polymers - thermo softening plastics


  Soften when heated and harden again when cooled

  Contain weak intermolecular forces which let the chains slide past each other

  Plastics made from these are stretchy and they also have a low melting point
• Types of polymers - thermosetting plastics

  Formed from polymers that harden or set permanently when formed, meaning thermosetting plastics can't be reshaped

  Contain strong intermolecular forces that hold polymer chains in place

  Plastics made of these polymers can't be stretched

  They are rigid and have a high melting point
• High density polythene HDE

  Uses a catalyst at 50 degrees and a slightly raised pressure

  Forms straight chained molecules

  Pack close together in a more crystalline structure

  High softening temperature

  Stronger than LDE

  Examples - shampoo bottles, toiletries
• Low density polythene LDE


  Formed using high pressure and a trace of oxygen

  Polymers are randomly branched

  Can be packed together tightly

  Lower softening temeprature

  Weaker than HDE

  Examples: food packaging