Ethylidene norbornene (ENB) is an
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...
that consists of an ethylidene (CH
3C(H)=) group attached to
norbornene. It is a colorless liquid. The molecule consists of two sites of
unsaturation, one of which participates in the
copolymer
In polymer chemistry, a copolymer is a polymer derived from more than one species of monomer. The polymerization of monomers into copolymers is called copolymerization. Copolymers obtained from the copolymerization of two monomer species are some ...
ization and the second of which (the ethylidene) undergoes vulcanization. It is a monomer in the production of the commercial polymer
EPDM. The compound consists of E- and Z-stereoisomers, but the mixtures are not separated.
It is prepared by isomerization of
vinyl norbornene, which in turn is obtained by the
Diels-Alder reaction of
butadiene
1,3-Butadiene () is the organic compound with the formula (CH2=CH)2. It is a colorless gas that is easily condensed to a liquid. It is important industrially as a precursor to synthetic rubber. The molecule can be viewed as the union of two viny ...
and
cyclopentadiene
Cyclopentadiene is an organic compound with the chemical formula, formula C5H6.LeRoy H. Scharpen and Victor W. Laurie (1965): "Structure of cyclopentadiene". ''The Journal of Chemical Physics'', volume 43, issue 8, pages 2765-2766. It is often ab ...
.
Safety
Its (intravenous, rabbit) ranges from 0.09 (male rabbit) to 0.11 ml/kg (female). It is also a neurotoxin.
References
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Cyclopentenes
Monomers