Industrial styrene production: by which process is styrene (the monomer for polystyrene) most commonly produced at scale?

Introduction / Context:
Styrene is a foundational monomer for plastics and elastomers (PS, ABS, SBR). Knowing its commercial route clarifies upstream petrochemical linkages and plant integration with ethylbenzene and benzene–ethylene feeds.

Given Data / Assumptions:

• Styrene monomer supply is tied to ethylbenzene.
• Processes should be feasible and widely adopted industrially.

Concept / Approach:
The overwhelmingly dominant route is catalytic dehydrogenation of ethylbenzene to styrene and hydrogen. Ethylbenzene is itself made by alkylating benzene with ethylene. Alternative listed routes are not commercial styrene routes.

Step-by-Step Solution:
Identify real-world dominant pathway: ethylbenzene → styrene + H2.Eliminate non-standard or unrelated reaction schemes.

Verification / Alternative check:
Refinery–petrochemical flow diagrams show styrene units fed by ethylbenzene dehydrogenation alongside SM/PO variants.

Why Other Options Are Wrong:
They do not represent practiced styrene manufacturing routes.

Common Pitfalls:
Confusing ethylbenzene dehydrogenation with unrelated ethanol or acetaldehyde chemistry.

Final Answer:
Catalytic dehydrogenation of ethylbenzene