Preparation of ethanol
Production of ethanol in the industry
- Addition reaction with water (steam)
- Catalyst: phosphoric acid
- Temperature: 300°C
- Pressure: 60 atm
\(C_2H_4(g) + H_2O(l) \xrightarrow[]{H_3PO_4} C_2H_5OH(l)\) |
Production of ethanol in the laboratory
- The fermentation process of carbohydrate or sugary substances like rice, barley or fruits
- These substances contain glucose.
- Zymase in yeast acts as a catalyst to convert glucose to ethanol.
\(C_6H_{12}O_6(aq) \xrightarrow[]{yeast} 2C_2H_5OH(l) + 2CO_2(g)\) |
Chemical properties of ethanol
- Combustion
- Combustion of ethanol in excess oxygen produces carbon dioxide and water.
\(C_2H_5OH(l) + 3O_2 (g) \rightarrow 2CO_2(g) + 3H_2O(l)\) |
- Oxidation
- Ethanol is oxidised by acidified potassium dichromate(VI) solution.
- Product: ethanoic acid
- Dichromate ion (orange) changes to chromium ion (green).
\(C_2H_5OH(l) \xrightarrow[]{[O]} CH_3COOH(l)\) |
- Dehydration
- A water molecule is eliminated from the reaction.
- Catalyst: sulphuric acid
- Temperature: 180°C
- Product: ethene
\(C_2H_5OH(l) \xrightarrow[]{H_2SO_4, 180^\circ C} C_2H_4(g) + H_2O(l)\) |