CAS number 126-99-8 YesY
ChemSpider 29102 YesY
KEGG C19208 YesY
ChEBI CHEBI:39481 YesY
RTECS number EL9625000
Jmol-3D images Image 1
Molecular formula C4H5Cl
Molar mass 88.5365 g/mol
Appearance Colorless liquid.
Density 0.9598 g/cm3, liquid.
Melting point

-130 °C, 143 K, -202 °F

Boiling point

59.4 °C, 333 K, 139 °F

Solubility in water 0.026 g/100 mL, liquid.
R-phrases R45, R11, R20/22,
R36/37/38, R48/20
S-phrases S53, S45
Main hazards Highly flammable, toxic.
NFPA 704
NFPA 704.svg
Flash point -15.6°C
Related compounds
Related Dienes Butadiene
Related compounds Vinyl chloride
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Chloroprene is the common name for the organic compound 2-chlorobuta-1,3-diene, which has the formula CH2=CCl-CH=CH2. This colorless liquid is the monomer for the production of the polymer polychloroprene, a type of synthetic rubber. Polychloroprene is better known to the public as Neoprene, the trade name given by DuPont.


Production of chloroprene

Chloroprene is produced in three steps from 1,3-butadiene: (i) chlorination, (ii) isomerization of part of the product stream, and (iii) dehydrochlorination of 3,4-dichloro-1-butene.

Chlorine adds to 1,3-butadiene to afford a mixture of 3,4-dichloro-1-butene and 2,3-dichloro-2-butene. The 2,3-chloro isomer is subsequently isomerized to 3,4 isomer, which in turn is treated with base to induce dehydrochlorination to 2-chlorobuta-1,3-diene. This dehydrohalogenation entails loss of a hydrogen atom in the 3 position and the chlorine atom in the 4 position thereby forming a double bond between carbons 3 and 4. In 1983, approximately 2,000,000 kg were produced in this manner.[1] The chief impurity in chloroprene prepared in this way is 1-chlorobuta-1,3-diene, which is usually separated by distillation.

Acetylene process

Until the 1960s, chloroprene production was dominated by the “acetylene process,” which was modeled after the original synthesis of vinylacetylene.[2] In this process, acetylene is dimerized to give vinyl acetylene, which is then combined with hydrogen chloride to afford 4-chloro-1,2-butadiene (an allene derivative), which in the presence of cuprous chloride, rearranges to the targeted 2-chlorobuta-1,3-diene:[1]

HC≡C-CH=CH2 + HCl → H2C=C=CH-CH2Cl

This process is very energy-intensive and has high investment costs. Furthermore, the intermediate vinyl acetylene is unstable.

This "acetylene process" has been replaced by a process which adds Cl2 to one of the double bonds in 1,3-butadiene instead, and subsequent elimination produces HCl instead, as well as chloroprene.


  1. ^ a b Manfred Rossberg, Wilhelm Lendle, Gerhard Pfleiderer, Adolf Tögel, Eberhard-Ludwig Dreher, Ernst Langer, Heinz Rassaerts, Peter Kleinschmidt, Heinz Strack, Richard Cook, Uwe Beck, Karl-August Lipper, Theodore R. Torkelson, Eckhard Löser, Klaus K. Beutel, “Chlorinated Hydrocarbons” in Ullmann’s Encyclopedia of Industrial Chemistry, 2006 John Wiley-VCH: Weinheim.DOI: 10.1002/14356007.a06_233.pub2
  2. ^ Wallace H. Carothers, Ira Williams, Arnold M. Collins, and James E. Kirby (1937). "Acetylene Polymers and their Derivatives. II. A New Synthetic Rubber: Chloroprene and its Polymers". J. Am. Chem. Soc. 53 (11): 4203–4225. doi:10.1021/ja01362a042. 

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Look at other dictionaries:

  • Chloroprène — Général Nom IUPAC 2 cholorobuta 1,3 diène No CAS …   Wikipédia en Français

  • chloroprène — ● chloroprène nom masculin Chlorobutadiène CH2≅CCl―CH≅CH2, dont la polymérisation donne un caoutchouc synthétique (Néoprène ou Duprène). chloroprène [klɔʀopʀɛn] n. m. ÉTYM. Mil. XXe; de chloro , et prène (→ Néoprène). ❖ ♦ Chim., techn. Dérivé du… …   Encyclopédie Universelle

  • chloroprene — [klôr′əprēn΄] n. [ CHLORO + (ISO)PRENE] a colorless liquid, H2C:CHCCl:CH2, made from acetylene: it can be polymerized to form neoprene …   English World dictionary

  • Chloroprene — A possible carcinogen (cancer causing agent) primarily used in the production of the elastomer polychloroprene (neoprene). The US government in 2000 classified chloroprene as reasonably anticipated to be a human carcinogen. In laboratory animal… …   Medical dictionary

  • chloroprene — chlorprenas statusas T sritis chemija formulė CH₂=CClCH=CH₂ atitikmenys: angl. chloroprene rus. хлоропрен ryšiai: sinonimas – 2 chlor 1,3 butadienas …   Chemijos terminų aiškinamasis žodynas

  • chloroprene rubber — chlorpreninis kaučiukas statusas T sritis chemija formulė Formulę žr. priede. priedas( ai) Grafinis formatas atitikmenys: angl. chloroprene rubber rus. найрит; неопреновый каучук; хлоропреновый каучук ryšiai: sinonimas – neopreninis kaučiukas …   Chemijos terminų aiškinamasis žodynas

  • chloroprene — noun Etymology: chlor + isoprene Date: 1931 a colorless liquid C4H5Cl used especially in making neoprene by polymerization …   New Collegiate Dictionary

  • chloroprene — /klawr euh preen , klohr /, n. a colorless, slightly water soluble liquid, C4H5Cl, usually produced by the reaction of vinylacetylene with hydrochloric acid, that polymerizes to neoprene. [1930 35; CHLORO 2 + (ISO)PRENE] * * * …   Universalium

  • chloroprene — noun The chlorinated derivative of butadiene 2 chloro 1,3 butadiene that is used (via polymerization) in the manufacture of synthetic rubber …   Wiktionary

  • chloroprene — chlo·ro·prene …   English syllables

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