3.12 Describe the dehydration of ethanol to ethene, using aluminium oxide.

• Ethanol > ethene + water
• C2H5OH > C2H4 + H2O

Aluminium oxide is a catalyst in this reaction

3.9 Describe the manufacture of ethanol by passing ethene and steam over a phosphoric acid catalyst at a temperature of about 300°C and a pressure of about 60–70 atm

Ethanol can be made by reacting ethene (from cracking crude oil fractions) with steam (aka the hydration of ethene).

• Ethene + steam > ethanol
• C2H4 + H2O > C2H5OH

Phosphoric acid is a catalyst for this reaction. You also need to remember:
- The pressure (60-70 atm) at which the reaction takes place
- The temperature (300°C)

The process is continuous (as long as there are always reactants)

The high pressure and temperature make the reaction happen really quickly. This is described as the dehydration of ethene (I'm pretty sure)