Difference between revisions of "Epichlorohydrin"

Latest revision as of 09:59, 20 September 2010

(±)-Epichlorohydrin[1]
Epichlorohydrin
Ball-and-stick model of the epichlorohydrin molecule
IUPAC name chloromethyloxirane
Other names epichlorohydrin 1-chloro-2,3-epoxypropane γ-chloropropylene oxide glycidyl chloride
style="background: #F8EABA; text-align: center;" colspan="2" | Identifiers
CAS number	106-89-8 Y
PubChem	7835
ChemSpider	7547
SMILES	Script error: No such module "collapsible list".
style="background: #F8EABA; text-align: center;" colspan="2" | Properties
Molecular formula	C3H5ClO
Molar mass	92.52 g/mol
Density	1.1812 g/cm3
Melting point	-25.6 °C
Boiling point	117.9 °C
style="background: #F8EABA; text-align: center;" colspan="2" | Hazards
MSDS	External MSDS
EU classification	Toxic T
NFPA 704	75px 3 3 2
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Epichlorohydrin is an organochlorine compound and an epoxide. This is a colorless liquid with a pungent, garlic-like odor, insoluble in water, but miscible with most polar organic solvents.^[2] Epichlorohydrin is a highly reactive compound and is used in the production of glycerol, plastics, epoxy glues and resins, and elastomers. In contact with water, epichlorohydrin hydrolyzes to 3-MCPD, a carcinogen found in food.

Production

Epichlorohydrin is manufactured from allyl chloride in two steps, beginning with the hydrochlorination using hypochlorous acid, which affords a mixture of two alcohols:^[3]

CH₂=CHCH₂Cl + HOCl → HOCH₂CHClCH₂Cl and, or ClCH₂CH(OH)CH₂Cl

300px

In the second step, this mixture is treated with base to give the epoxide:

HOCH₂CHClCH₂Cl and, or ClCH₂CH(OH)CH₂Cl + NaOH → CH₂CHOCH₂Cl + NaCl + H₂O

443px

In this way, more than 700,000 tons of epichlorohydrin are produced annually.^[4]

Applications

Glycerol and epoxy resins synthesis

Epichlorohydrin is mainly converted to Bisphenol A diglycidyl ether, a building block in the manufacture of epoxy resins. It is also a precursor to monomers for other resins and polymers.

Another usage is the conversion to synthetic glycerol:

CH₂CHOCH₂Cl + 2 H₂O → HOCH₂CH(OH)CH₂(OH) + HCl

However, the rapid increase in biodiesel production has led to a glut of glycerol on the market, rendering this process uneconomic. In fact, ways to perform the reverse process are now being researched, to produce epichlorohydrin from the now less valuable glycerol, a process now commercialised by Solvay SA with a commercial demo site producing 10 000 tons annually.

Minor and niche applications

Epichlorohydrin is a versatile precursor in the synthesis of many organic compounds. For example, it is converted to glycidyl nitrate, an energetic binder used in explosive and propellant compositions.^[5] The epichlorohydrin is reacted with an alkali nitrate, such as sodium nitrate, producing glycidyl nitrate and alkali chloride. It used as a solvent for cellulose, resins and paints and it has found use as an insect fumigant.^{[citation needed]}

Epichlorohydrin is used in paper reinforcement (used for instance in the food industry to manufacture tea bags, coffee filters, and sausage/salami casings) and water purification.^[6]

An important biochemical application of epichlorohydrin is its use as crosslinking agent for the production of Sephadex size-exclusion chromatographic resins from dextrans ^[7]

Safety

Epichlorohydrin is irritating and moderately toxic as well as carcinogenic.^[2]

See also

• Epoxy resins

References

1. ↑ Merck Index, 12th Edition, 3648.
2. ↑ ^{2.0 2.1} EPA consumer factsheet
3. ↑ Guenter Sienel, Robert Rieth, Kenneth T. Rowbottom "Epoxides" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.
4. ↑ 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.
5. ↑ Gould, R.F. Advanced Propellant Chemistry, ACS Chemistry Series 54, 1966
6. ↑ http://www.chemicalsubstanceschimiques.gc.ca/challenge-defi/batch-lot-2/106-89-8_e.html
7. ↑ http://www5.gelifesciences.com/aptrix/upp00919.nsf/content/EE755AF81C96972FC1256EB40048417B?OpenDocument&Path=Catalog&Hometitle=Catalog&entry=1&newrel&LinkParent=C1256FC4003AED40-342B143523C3C764C12570F600421582_RelatedLinksNew-C821BEC677D8448BC1256EAE002E3030&newrel&hidesearchbox=yes&moduleid=166703

cs:Epichlorohydrin de:Epichlorhydrin nl:Epichloorhydrine ja:エピクロロヒドリン pl:Epichlorohydryna sv:Epiklorhydrin zh:环氧氯丙烷