Ethylbenzene to styrene: By which fundamental reaction step is styrene industrially produced from ethylbenzene?

Introduction / Context:
Styrene is a major monomer for polystyrene and ABS. Its principal industrial route is from ethylbenzene in large, integrated plants.

Given Data / Assumptions:

• Feed: ethylbenzene (formed upstream via benzene + ethylene alkylation).
• Catalyst: iron oxide with promoters; steam is co-fed.
• Reaction conditions: high temperature, equilibrium limited.

Concept / Approach:
The key chemistry is endothermic dehydrogenation: ethylbenzene → styrene + hydrogen. Steam suppresses coke, shifts equilibrium by diluting products, and provides heat capacity. Alternative oxidative dehydrogenation exists but the classical route is catalytic dehydrogenation.

Step-by-Step Solution:
Identify process chemistry → remove H2 from side chain.Select dehydrogenation as the correct reaction class.

Verification / Alternative check:
Process flow diagrams show ethylbenzene dehydrogenation furnaces followed by separation of H2, styrene, and unreacted ethylbenzene.

Why Other Options Are Wrong:

• Oxidation route is not the mainstream commercial method.
• Alkylation describes EB synthesis, not conversion to styrene.
• Dehydration/hydrocracking do not apply.

Common Pitfalls:
Mixing up the upstream EB formation step (alkylation) with the downstream styrene step (dehydrogenation).

Final Answer:
Dehydrogenation