Ethanol can be produced from glucose using yeast as a catalyst. The process is known as fermentation.C6H12O6 → 2CO2 + 2C2H5OHThe industrial production of ethanol is by the hydration of ethene obtained from crude oil. The catalyst is phosphoric acid adsorbed on silica.CH2=CH2 + H2O ⇌ C2H5OHA high pressure and low temperature will give the maximum yield. Using excess steam will force the equilibrium to the right.However, high pressure increases the cost of the plant and tends to cause ethene to polymerise. Low temperatures will reduce the rate of reaction. Too much steam dilutes the catalystIn practice temperatures of about 570K and 6500kPa are used. This gives a yield of about 5% and the remaining reactants are recycled.
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Specification: AQA Chemistry (7404), AS-level, 3.1.6.1 Chemical equilibria and Le Chatelier's principle. Topic: Equilibria.
Key terms in this lesson
- Catalyst
- A substance that increases the rate of a chemical reaction without being used up, by providing an alternative reaction pathway with a lower activation energy.
More in Equilibria
- Changing Temperature
- Catalysts
- Equilibrium Reactions in Industry
- Ammonia
- Methanol
- The Equilibrium Constant Kc
- Finding the Value of Kc
- Example Question - 1
All 20 lessons in Equilibria · All AQA AS-level Chemistry topics