6.1.6 - Types of Organic Reaction

• what's an addition reaction?

  reaction where 2 molecules are joined together to form a single product
• unsaturated compounds in addition reactions

  can be saturated in an addition reaction with hydrogen in the presence of a catalyst in a hydrogenation reaction

  also called a reduction reaction
• what's polymerisation?

  addition reaction where small molecules (monomers) join together forming a giant molecule (polymer)
• what's elimination

  reaction which produces an unsaturated product by loss of atoms or groups from adjacent carbon atoms
• what's substitution?

  reaction where an atom or group is replaced by another atom or group

  (like in halogenoalkanes)
• what's hydrolysis?

  reaction where a compound splits apart by adding water

  catalysed by aids or alkalis

  often chemical attack is by nucleophiles
• oxidation

  loss of electrons
• reduction

  gain of electrons
• example of addition reactions

  hydrogen adds to C=C bonds in alkenes in the presence of a platinum or palladium catalyst at room temperature or on heating to 150°C with a nickel catalyst
• example of polymerisation

  ethene molecules join together to form poly(ethene)
• examples of elimination

  removal of hydrogen halide from halogenoalkane in alkaline conditions to produce an alkene

  removal of water from an alcohol in acidic conditions to produce an alkene
• example of substitution

  replacement of hydrogen atoms in alkanes by chlorine or bromine in the presence of UV light
• example of hydrolysis

  hydrolysis of halogenoalkanes where water & halogenoalkanes split into alcohols & hydrogen halides

  very slow in the absence of alkali