Production of ethanol

Question 1

What is the molecular formula of ethanol?

Answer 1

• C2H5OH

Question 2

What are the main uses of ethanol?

Answer 2

• As a chemical feedstock: to produce other organic compounds
• As a biofuel: ethanol can be burnt like petrol
• Used in alcoholic drinks

Question 3

What are the different ways that ehtanol can be produced

Answer 3

• Ethene and steam
• Fermentation

Question 4

What is the equation for producing ethanol using ethene and steam and its pros and cons?

Answer 4

• C2H4 + H2O —> C2H5OH (using high temperatures and a catalyst)
• Pros: ethene is cheap, the reaction is cheap and efficient
• Cons: ethene is made form crude oil so is non-renewable

Question 5

What is the equation for producing ethanol from fermentation and its pros and cons? What conditions are required?

Answer 5

• C6H12O6 —> 2C2H5OH + CO2
• Done by adding yeast to the dissolved sugar solution and fermenting it between 15 and 35 C in anaerobic conditions
• Pros: sugar/glucose that is used is a renewable resource
• Cons: the process is relatively slow, ethanol produced isn’t pure

Question 6

What happens to the yeast in fermentation?

Answer 6

• After the concentration of alcohol reaches 15%, the yeast gets killed off so the vessel must be emptied and fermentation must be restarted