1,4-Dichlorobut-2-ene

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1,4-Dichlorobut-2-ene
Trans-1,4-Dichlorobutene.svg
1,4-Dichlorobut-2-ene molecule
Names
IUPAC name
1,4-Dichlorobut-2-ene
Other names
trans-1,4-Dichlorobutene
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.003.437
EC Number 203-779-7
Properties
C4H6Cl2
Molar mass 124.99 g·mol−1
Appearance Colorless liquid
Density 1.13 g/mL
Melting point 1 °C (34 °F; 274 K)
Boiling point 125.5 °C (257.9 °F; 398.6 K)
Hazards[1]
GHS pictograms The skull-and-crossbones pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The health hazard pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The environment pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word DANGER
H350, H330, H311, H301, H314, H410
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

1,4-Dichlorobut-2-ene is a chlorinated butene. It is an intermediate in the industrial production of chloroprene, and the main impurity in technical grade chloroprene,[2] the (E)-isomer is also one of the starting materials for Birman's total synthesis of the poriferic natural product sceptrin.[3]

Production of chloroprene[edit]

Chloroprene is a monomer for the production of synthetic rubbers such as Neoprene, it is produced from butadiene in a three-step process. The first step is the liquid- or vapour-phase chlorination of butadiene to a mixture of 3,4-dichlorobut-1-ene and 1,4-dichlorobut-2-ene (both isomers); in the second step, the mixture of 1,4-dichlorobut-2-ene and 3,4-dichlorobut-1-ene is isomerized to pure 3,4-dichlorobut-1-ene by heating to temperatures of 60–120 °C in the presence of a catalyst. Finally, dehydrochlorination (elimination of hydrogen chloride) of 3,4-dichlorobut-1-ene with dilute sodium hydroxide solution in the presence of polymerization inhibitors gives crude chloroprene.[4]

References[edit]

  1. ^ Index no. 602-073-00-X of Annex VI, Part 3, to Regulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 December 2008 on classification, labelling and packaging of substances and mixtures, amending and repealing Directives 67/548/EEC and 1999/45/EC, and amending Regulation (EC) No 1907/2006. OJEU L353, 31.12.2008, pp 1–1355 at p 473.
  2. ^ Re-evaluation of Some Organic Chemicals, Hydrazine and Hydrogen Peroxide (PDF), IARC Monographs on the Evaluation of Carcinogenic Risks to Humans 71, Lyon, France: International Agency for Research on Cancer, 1999, pp. 227–50, ISBN 92-832-1271-1 .
  3. ^ Birman, Vladimir B.; Jiang, Xun-Tian (2004), "Synthesis of Sceptrin Alkaloids", Org. Lett., 6 (14): 2369–71, doi:10.1021/ol049283g, PMID 15228281 . Baran, Phil S.; Zografos, Alexandros L.; O'Malley, Daniel P. (2004), "Short Total Synthesis of (±)-Sceptrin", J. Am. Chem. Soc., 126 (12): 3726–27, doi:10.1021/ja049648s, PMID 15038721 .
  4. ^ Kleinschmidt, P. (1986), "Chlorinated hydrocarbons. 6.4. 2-Chloro-1,3-butadiene", in Gerhartz, W.; Yamamoto, Y. S., Ullmann’s Encyclopedia of Industrial Chemistry, A6 (5th ed.), Weinheim: VCH, pp. 315–18 . Stewart, C. A., Jr. (1993), "Chlorocarbons, -hydrocarbons (chloroprene)", in Kroschwitz, J. I.; Howe-Grant, M., Kirk-Othmer Encyclopedia of Chemical Technology, 6 (4th ed.), New York: John Wiley, pp. 70–78 .