Indian feedstock history: which starting material has been used in India for producing butadiene?

Introduction / Context:
Butadiene is a key monomer for synthetic rubbers (SBR, polybutadiene). Historically, multiple routes existed globally; in India, ethanol-derived routes (e.g., Lebedev process) have been notable.

Concept / Approach:
Ethanol can be converted to butadiene through catalytic dehydrogenation–condensation sequences. Other listed feedstocks do not represent India’s historical starting material choice for butadiene.

Final Answer:
Ethyl alcohol (ethanol)