Reactions of Alcohols

• Substitution reactions of alcohols

  • Alcohols will react with compounds containing halide ions (such as NaBr) in a substitution reaction.
  • The hydroxyl (-OH) group is replaced by the halide, so the alcohol is transformed into a haloalkane.
  • The reaction also requires an acid catalyst, such as H2SO4

  
• Example of a substitution reactions of an alcohol

  
• Elimination reactions of alcohols

  • Alkenes are really useful organic chemicals that can be used as starting products for lots of organic chemicals such as polymers.
  • You can make alkenes by eliminating water from alcohols in an elimination reaction.
  • The alcohol is mixed with an acid catalyst either concentrated sulfuric acid (H2SO4) or concentrated phosphoric acid (H3PO4).
  • The mixture is then heated.
  • Water is eliminated from the alcohol, so this reaction is sometimes called a dehydration reaction.

  
• An example of an Elimination reaction of an alcohols

  
• Elimination reactions of alcohols

  • The water molecule that is eliminated from an alcohol when it forms an alkene is made up from the hydroxyl group and a hydrogen atom that was bonded to a carbon atom adjacent to the hydroxyl carbon.
  • This means that often there are two possible alkene products from one elimination reaction depending on which side of the hydroxyl group the hydrogen is eliminated from.
  • Sometimes an alkene product can form ElZ isomers- if this is the case then a mixture of both isomers will form.