1. Higher Chemistry Unit 2(c) Uses of addition reactions in industry

2. After today’s lesson you should be able to: give two examples of addition reactions used in industry. state two ways in which ethanol is produced and be able to write word and formulae equations for both methods. SAFELY carry out an experiment to convert ethanol back to its feedstock ethene.

3. Addition reaction in industry The production of margarine Margarine is made when hydrogen is added to the carbon to carbon double bonds in vegetable oils in the presence of a nickel catalyst.

4. The production of ‘industrial’ ethanol Ethanol can be made by adding water to ethene in the presence of the catalyst phosphoric acid. C 2 H 4 + H 2 O → C 2 H 5 OH The addition of water to an alkene is known as ‘hydration’.

5. Ethanol Because ‘industrial’ ethanol is unfit for human consumption the ethanol used in alcoholic drinks has to be made by fermentation of glucose. C 6 H 12 O 6 + H 2 O → C 2 H 5 OH + CO 2 Fermentation of glucose is a much slower reaction than hydration of ethene.

6. Dehydration Ethanol can be ‘dehydrated’ back to ethene in the presence of the catalyst aluminium oxide. C 2 H 5 OH → C 2 H 4 + H 2 O [Complete workcard 2]