Ethylidene norbornene

Ethylidene norbornene
Names
	Other names 2-ethylidene-5-norbornene
Identifiers
CAS Number	16219-75-3 ;
3D model (JSmol)	Interactive image;
ChEMBL	ChEMBL1427645;
ChemSpider	4517512;
EC Number	240-347-7;
PubChem CID	5365543;
UNII	Q4D40UVR0R ;
UN number	1993 1992
CompTox Dashboard (EPA)	DTXSID601270050 ;
	InChI InChI=1S/C9H12/c1-2-8-5-7-3-4-9(8)6-7/h2-4,7,9H,5-6H2,1H3/b8-2+ Key: OJOWICOBYCXEKR-KRXBUXKQSA-N;
	SMILES C/C=C/1\CC2CC1C=C2;
Properties
Chemical formula	C9H12
Molar mass	120.195 g·mol−1
Appearance	colorless liquid
Density	0.893 g/mL
Melting point	−80 °C (−112 °F; 193 K)
Boiling point	146 °C (295 °F; 419 K)
Hazards
	GHS labelling:[1]
Pictograms
Signal word	Danger
Hazard statements	H226, H304, H315, H317, H319, H332, H335, H373, H411
Precautionary statements	P210, P233, P240, P241, P242, P243, P260, P261, P264, P264+P265, P271, P272, P273, P280, P301+P316, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P317, P319, P321, P331, P332+P317, P333+P317, P337+P317, P362+P364, P370+P378, P391, P403+P233, P403+P235, P405, P501
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Ethylidene norbornene (ENB) is an organic compound that consists of an ethylidene (CH₃C(H)=) group attached to norbornene. It is a colorless liquid. The molecule consists of two sites of unsaturation. The compound consists of (E)- and (Z)-stereoisomers, but the mixtures are typically not separated.

Preparation and use

It is prepared by isomerization of vinyl norbornene, which in turn is obtained by the Diels-Alder reaction of butadiene and cyclopentadiene.^[1]

It is a monomer that used in the production of the commercial polymer EPDM. Only the ring alkene participates in the copolymerization. The exocyclic double bond (the ethylidene group) undergoes sulfur vulcanization.

Safety

Its LD₅₀ (intravenous, rabbit) ranges from 0.09 (male rabbit) to 0.11 ml/kg (female). It is also a neurotoxin.^[2]

References

^ Behr, Arno (2000). "Organometallic Compounds and Homogeneous Catalysis". Ullmann's Encyclopedia of Industrial Chemistry. p. 10. doi:10.1002/14356007.a18_215. ISBN 3527306730.
^ Ballantyne, Bryan; Myers, Roy C.; Klonne, Dennis R. (1997). "Comparative acute toxicity and primary irritancy of the ethylidene and vinyl isomers of norbornene". Journal of Applied Toxicology. 17 (4): 211–221. doi:10.1002/(SICI)1099-1263(199707)17:4<211::AID-JAT430>3.0.CO;2-X. PMID 9285533. S2CID 21154862.

[1] Behr, Arno (2000). "Organometallic Compounds and Homogeneous Catalysis". Ullmann's Encyclopedia of Industrial Chemistry. p. 10. doi:10.1002/14356007.a18_215. ISBN 3527306730.

[2] Ballantyne, Bryan; Myers, Roy C.; Klonne, Dennis R. (1997). "Comparative acute toxicity and primary irritancy of the ethylidene and vinyl isomers of norbornene". Journal of Applied Toxicology. 17 (4): 211–221. doi:10.1002/(SICI)1099-1263(199707)17:4<211::AID-JAT430>3.0.CO;2-X. PMID 9285533. S2CID 21154862.

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