isoprene

/ahy-suh-preen/US // ˈaɪ səˌprin //UK // (ˈaɪsəʊˌpriːn) //

异戊二烯,异戊二烯橡胶,异戊二烯二烯,异戊二烯二烯酮

Definitions

n.名词 noun

1
Chemistry.
- : a colorless, volatile, water-insoluble liquid, C5H8, of the terpene class, usually obtained from rubber or from oil of turpentine by pyrolysis: used chiefly in the manufacture of synthetic rubber by polymerization.

You will see that the isoprene consists of a chain of four carbon atoms (represented by the C's) with an extra carbon on the side.
What reagent could be found that would reverse the reaction and convert the liquid isoprene into the solid rubber?
From fusel oil by the use of chlorine isoprene can be prepared, so the chain was complete.
We can get isoprene by the distillation of turpentine—but why not bleed a rubber tree as well as a pine tree?
Petroleum when cracked up to make gasoline gives isoprene or other double-bond compounds that go over into some form of rubber.