<unk>  is a simple conjugated diene. It is an important industrial chemical used as a monomer in the production of synthetic rubber.  When the word<unk>  is used, most of the time it refers to<unk> .
The name<unk>  can also refer to the isomer,<unk> , which is a cumulated diene. However, this allene is difficult to prepare and has no industrial significance.
1,3-Butadiene
Benzene
Ether
Methylene diphenyl diisocyanate
Cyclohexane
Acetylene
Vinyl chloride
Dimethyl phthalate