Norbornene

Norbornene or norbornylene or norcamphene is a bridged cyclic hydrocarbon. It is a white solid with a pungent sour odor. The molecule consists of a cyclohexene ring bridged with a methylene group in the para position. The molecule carries a double bond which induces significant ring strain and significant reactivity.

Norbornene, like many of its derivatives, is made by a Diels-Alder reaction of cyclopentadiene and ethylene. Related bicyclics are norbornadiene which has the same carbon skeleton but with two double bonds and norbornane which is completely saturated without double bonds.

Norbornene undergoes an acid-catalyzed hydration reaction with water to form norborneol. This reaction is of great interest to chemists studying non-classical ions.

Polynorbornenes
Norbornenes are important monomers in ring-opening metathesis polymerizations (ROMP) with for instance the Grubbs' catalyst. Polynorbornenes are polymers with high glass transition temperatures and high optical clarity.



In addition to ROMP polymerization, norbornene monomers also undergo vinyl-addition polymerization.

Ethylidene norbornene is a related monomer derived from cyclopentadiene and butadiene.

Practical Uses
Norbornene does not have as many practical uses as ethylene or other commodity chemicals. It is utilized to make pharmaceutical intermediates, pesticide compounds, specialty fragrances and in general organic synthesis. When combined with ethylene, norbornene will react and turn into a cyclic olefin copolymer.