1. Lesson 11 - Ethanol Learning Objectives:
Describe the two methods for producing ethanol.
Describe the advantages and disadvantages of each method.

2. Ethanol is an important industrial product
Organic Chemicals
Cosmetics
Drugs
Inks
Detergents
Bioethanol fuel

3. General Formula Alcohols are NOT hydrocarbons.
They have the extra group –OH.
Example:
Ethanol = C2H5OH

4. Making Ethanol from Crude Oil
Ethene is produced from cracking crude oil.
Ethene can then be reacted with steam, using a catalyst, to produce ethanol.
Cracking
Can you think of why this is called hydration?
Hydration

5. Fermentation
Ethanol can also be made from the fermentation of carbohydrates (from plants).
Carbohydrates are broken down into sugars and then converted into ethanol by enzyme action by yeast.
Sugar cane and sugar beet

6. Fermentation C6H12O6  2C2H5OH + 2CO2
yeast
C6H12O6  2C2H5OH + 2CO2
Glucose  Ethanol + Carbon Dioxide
Yeast are microorganisms.
They feed on sugar and in the absence of oxygen release energy through anaerobic respiration.
This produces ethanol and carbon dioxide as waste.

7. Distillation

8. Ethanol as Biofuel Biofuel = fuel made from plant material (renewable)
Being researched as an alternative to petrol so that we are no longer so reliant on crude oil, which is a non-renewable resource.

9. Carbon Neutral
The combustion of ethanol produces the same amount of carbon dioxide as the plant absorbed while living, so ethanol is said to be a carbon neutral fuel.
This is seen as a positive because CO2 is a greenhouse gas associated with global warming.
However, this does not take into account other energy costs such as transportation or processing.

10. Hydration of Ethene vs. Fermentation
Advantages
Disadvantages
Advantages
Disadvantages

11. Hydration of Ethene vs. Fermentation
Advantages
No waste products
Produces ethanol continuously
Disadvantages
Uses crude oil which is non-renewable
Requires a lot of energy for high heat and high pressure
Advantages
Renewable (uses plants)
Uses less energy, lower temperatures
Disadvantages
Slow, batch process, have to start a new batch once yeast die
Produces CO2 as waste