Allyl chloride

Allyl chloride is the organic compound with the formula CH₂=CHCH₂Cl. This colorless liquid is insoluble in water but soluble in common organic solvents. It is mainly converted to epichlorohydrin, used in the production of plastics. It is a chlorinated derivative of propylene. It is an alkylating agent, which makes it both useful and hazardous to handle.<ref name=Ullmann/>

Production

Laboratory scale

Allyl chloride was first produced in 1857 by Auguste Cahours and August Hofmann by reacting allyl alcohol with phosphorus trichloride.<ref>Hofmann. Augustus William and Cahours. Augustus (1857) "Researches on a new class of alcohols," Philosophical Transactions of the Royal Society of London, 147: 555–574 ; see pp. 558–559.</ref><ref name=Ullmann>Ludger Krähling, Jürgen Krey, Gerald Jakobson, Johann Grolig, Leopold Miksche "Allyl Compounds" in Ullmann's Encyclopedia of Industrial Chemistry Wiley-VCH, Weinheim, 2005. Published online: 15 June 2000.</ref> Modern preparation protocols economize this approach, replacing relatively expensive phosphorus trichloride with hydrochloric acid and a catalyst such as copper(I) chloride.<ref name=Vogel>Template:Cite book</ref>

Industrial scale

Allyl chloride is produced by the chlorination of propylene. At lower temperatures, the main product is 1,2-dichloropropane, but at 500 °C, allyl chloride predominates, being formed via a free radical reaction:

<chem>CH3CH=CH2 + Cl2 -> ClCH2CH=CH2 + HCl</chem>

An estimated 800,000 tonnes were produced this way in 1997.<ref name=Ullmann/>

Reactions and uses

The great majority of allyl chloride is converted to epichlorohydrin.<ref name=Ullmann/> Other commercially significant derivatives include allyl alcohol, allylamine, allyl isothiocyanate (synthetic mustard oil),<ref name=Ullmann2>F. Romanowski, H. Klenk "Thiocyanates and Isothiocyanates, Organic" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH: Weinheim. Template:Doi</ref> and 1-bromo-3-chloropropane.

As an alkylating agent, it is useful in the manufacture of pharmaceuticals and pesticides, such as mustard oil.

Illustrative reactions

Illustrative of its reactivity is its cyanation to allyl cyanide (CH₂=CHCH₂CN).<ref>Template:OrgSynth</ref> Being a reactive alkyl halide, it undergoes reductive coupling to give diallyl:<ref>Template:Cite journal</ref>

<chem>2 ClCH2CH=CH2 + Mg -> (CH2)2(CH=CH2)2 + MgCl2</chem>

It undergoes oxidative addition to palladium(0) to give allylpalladium chloride dimer, (C₃H₅)₂Pd₂Cl₂. Dehydrohalogenation gives cyclopropene.

Safety

Allyl chloride is highly toxic and flammable. Eye effects may be delayed and may lead to possible impairment of vision.<ref>Template:Cite web</ref>

See also

• Allyl
• Allyl bromide
• Allyl iodide

External links

• Template:ICSC
• Template:PGCH
• IARC Monograph *Allyl chloride.