Crotyl chloride

Crotyl chloride
Names
	Preferred IUPAC name (2E)-1-Chlorobut-2-ene
	Other names 1-Chloro-2-butene, 1-chlorobut-2-ene, 2-butenyl chloride, gamma-methylallyl chloride
Identifiers
CAS Number	591-97-9 ;
3D model (JSmol)	Interactive image;
Beilstein Reference	605304
ChemSpider	553496;
ECHA InfoCard	100.008.855
PubChem CID	637923;
RTECS number	EM4264000;
UNII	G6Y5C34N83 ;
CompTox Dashboard (EPA)	DTXSID5052258 ;
	InChI InChI=1S/C4H7Cl/c1-2-3-4-5/h2-3H,4H2,1H3/b3-2+ Key: YTKRILODNOEEPX-NSCUHMNNSA-N; InChI=1/C4H7Cl/c1-2-3-4-5/h2-3H,4H2,1H3/b3-2+ Key: YTKRILODNOEEPX-NSCUHMNNBH;
	SMILES C/C=C/CCl;
Properties
Chemical formula	C4H7Cl
Molar mass	90.55 g·mol−1
Appearance	Liquid
Density	0.949 g/cm3
Melting point	−65 °C (−85 °F; 208 K)
Boiling point	84 °C (183 °F; 357 K)
Vapor pressure	37084 mmHG
Hazards
NFPA 704 (fire diamond)	2 3 2
Flash point	−15 °C (5 °F; 258 K)
Autoignition; temperature	510 °C (950 °F; 783 K)
Related compounds
Related chloroalkenes	Allyl chloride; Methallyl chloride
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Crotyl chloride is an organochloride with the molecular formula C₄H₇Cl or H₃C(CH)₂CH₂Cl.^[1] It is a derivative of 2-butene with a chlorine atom at a terminal carbon. It exhibits cis-trans isomerism about the double bond; the (E) isomer predominates in commercial preparations.^[2]

Preparation

It can be produced by the chlorination of crotyl alcohol by chlorinating agents such as triphenylphosphine dichloride.^[2]

Applications

Treatment of crotyl halides with magnesium produces crotyl Grignard reagents. The chloride is more stable than the bromide.^[3] These reagents can then be used in the Grignard reaction for crotylation of carbonyl compounds.^[4]

Dehydrohalogenation of crotyl chloride was once used as a laboratory route to produce butadiene, though the pyrolysis of cyclohexene is preferred according to Organic Syntheses.^[5] Crotyl chloride may be used as a model compound for other allylic hydrochlorocarbons.^[6]

References

^ NIST Web Book
^ ^a ^b d'Angelo, Lihong L. (2001). "Crotyl Chloride". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rc254. ISBN 0-471-93623-5.
^ Florio, Saverio; Capriati, Vito (2001). "Crotylmagnesium Bromide". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rc258. ISBN 0-471-93623-5.
^ Matsukawa, Satoru; Funabashi, Yohei; Imamoto, Tsuneo (2003). "Regioselective allylation reactions using crotyl Grignard reagent–CeCl3 systems". Tetrahedron Letters. 44 (5): 1007–1010. doi:10.1016/S0040-4039(02)02741-7.
^ E. B. Hershberg and John R. Ruhoff (1937). "1,3-butadiene". Organic Syntheses. 17: 25.
^ Purmova, Jindra; Pauwels, Kim F. D.; Van Zoelen, Wendy; Vorenkamp, Eltjo J.; Schouten, Arend J.; Coote, Michelle L. (2005). "New Insight into the Formation of Structural Defects in Poly(Vinyl Chloride)". Macromolecules. 38 (15): 6352–6366. Bibcode:2005MaMol..38.6352P. doi:10.1021/ma050035p.

[nist-1] NIST Web Book

[ereagent-2] 'Angelo, Lihong L. (2001). "Crotyl Chloride". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rc254. ISBN 0-471-93623-5.

[3] Florio, Saverio; Capriati, Vito (2001). "Crotylmagnesium Bromide". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rc258. ISBN 0-471-93623-5.

[4] Matsukawa, Satoru; Funabashi, Yohei; Imamoto, Tsuneo (2003). "Regioselective allylation reactions using crotyl Grignard reagent–CeCl3 systems". Tetrahedron Letters. 44 (5): 1007–1010. doi:10.1016/S0040-4039(02)02741-7.

[5] E. B. Hershberg and John R. Ruhoff (1937). "1,3-butadiene". Organic Syntheses. 17: 25.

[6] Purmova, Jindra; Pauwels, Kim F. D.; Van Zoelen, Wendy; Vorenkamp, Eltjo J.; Schouten, Arend J.; Coote, Michelle L. (2005). "New Insight into the Formation of Structural Defects in Poly(Vinyl Chloride)". Macromolecules. 38 (15): 6352–6366. Bibcode:2005MaMol..38.6352P. doi:10.1021/ma050035p.

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