Learning focus
Develop accurate organic nomenclature, connect functional groups to reactions, draw structural and polymer formulae, interpret industrial processes and apply evidence to unfamiliar compounds.
Equation
Ethene reacts with steam reversibly: C2H4 + H2O(g) <-> C2H5OH. The process uses 300 C, 6000 kPa/60 atm and an acid catalyst.
Raw materials
Ethene is usually obtained from cracking petroleum fractions, so the traditional feedstock is non-renewable. Steam is readily available.
Continuous process
The process is fast and continuous. Ethanol is separated and unreacted ethene and steam are recycled, improving overall conversion.
Condition compromise
High pressure favours ethanol because two gas molecules form one. A moderate high temperature gives a useful rate while limiting equilibrium disadvantages for the exothermic forward reaction, although detailed equilibrium treatment may be integrated from Volume 4.
High-value recall and connections
Essential recall: What are the reactants? Ethene and steam. What pressure is used? 6000 kPa or 60 atm. What happens to unreacted gases? They are recycled. Practical connection: Interpret a process-flow diagram and identify feed, catalyst, reactor, separator and recycle stream. Examination connection: State all three typical conditions when asked: 300 C, 6000 kPa and an acid catalyst.
Practical or data skill
Interpret a process-flow diagram and identify feed, catalyst, reactor, separator and recycle stream.
Examination tip
State all three typical conditions when asked: 300 C, 6000 kPa and an acid catalyst.
Review questions and suggested answers
Question 1
What are the reactants?
Suggested answer
Ethene and steam.
Question 2
What pressure is used?
Suggested answer
6000 kPa or 60 atm.
Question 3
What happens to unreacted gases?
Suggested answer
They are recycled.
