ENB or ethylidenenorbornene is a bicyclic monomer and intermediate that contains two double bonds, each with quite different reactivity. Thus, it is possible to react one of the double bonds, and retain the other double bond for subsequent reaction.
ENB is used predominantly as a diene monomer in the manufacture of EPDM (Ethylene-Propylene-Diene-monomer) rubber.
ENB is registered in chemical abstracts under bicyclo(2.2.1)hept-2-ene,5-ethylidene. The CAS registry number is 16219-75-3. Its EINICS number is 240-347-7 and the MITI number is D 44 602.
ENB is not listed in the EEC Annex One, but is listed in the TSCA (USA), in the AICS/NICNAS and in the DSL/NDSL.