Crude Oil, Alkanes and Alkenes

Crude Oil, Alkanes and Alkenes

1. Crude Oil

   • Mixture of many compunds
   • Mainly made of hydrocarbons
   • Hydrocarbons contain only hydrogen and Carbon
   • Most of the hydrocarbons are Alkanes

2. Alkanes

   • Alkanes are a family of simple hydrocarbons
   • Alkanes are always covalently bonded
   • General Formula for Alkanes is: C n H 2n+2
   • Have no double bonds
   • Saturated Molecules, have the maximum possible single bonds
   • Isomers of Alkanes are exactly the same except that their structure is different
   • Burning Alkanes
     • Burn in oxygen or react with Halogens
     • In complete combustion it produces Carbon Dioxide and Water
     • In incomplete combustion it produces Carbon(as soot), Carbon Monoxide and water
   • Reacting with Halogens
     • An alkane will react with a halogen in the presence of UV light
       • A substitution reaction occurs
     • A substitution reaction is when the Halogen replaces the Hydrogen in the hydrocarbon
       • E.g. Methane + Bromine => Bromomethane + Hydrogen Bromide
   • The first five Alkanes are:
     • Methane CH4
     • Ethane C2H6
     • Propane C3H8
     • Butane C4H10
     • Pentane C5H12

3. Cracking

   • The process of breaking large alkanes into smaller ones
   • Performed by passing the alkane over a hot Aluminium Oxide Catalyst
   • Cracking an Alkane produces an Alkene
   • E.g. Cracking Propane would produce Propene

4. Fractional Distillation of Crude Oil

   • Crude Oil is heated before entering the Fractionating Column
   • The Fractionating Column has a temperature gradient
     • Hottest at the bottom, Coolest at the top
   • Heavier hydrocarbons remain at the bottom, lighter ones rise
   • The height a hydrocarbon reaches corresponds to the temperature in the column at which it can be condensed
   • Crude Oil contains more of the heavier, less useful alkanes
     • Larger alkanes can be converted into smaller ones via cracking

5. Alkenes

   • Created by cracking alkanes
   • General formula is 2n+2
   • Can be turned into polymers by addition polymerisation