Chemical Properties of Alcohol


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 
\(C_2H_5OH(l) \xrightarrow[]{H_2SO_4, 180^\circ C} C_2H_4(g) + H_2O(l)\)