Epichlorohydrin

(±)-Epichlorohydrin

Ball-and-stick model of the epichlorohydrin molecule
Names
IUPAC name chloromethyloxirane
Other names epichlorohydrin 1-chloro-2,3-epoxypropane γ-chloropropylene oxide glycidyl chloride
Identifiers
CAS Number	106-89-8 Y
3D model (JSmol)	Interactive image
ChemSpider	13837112
ECHA InfoCard	100.003.128
PubChem CID	7835
CompTox Dashboard (EPA)	DTXSID1020566
InChI InChI=1/C3H5ClO/c4-1-3-2-5-3/h3H,1-2H2 Key: BRLQWZUYTZBJKN-UHFFFAOYAY
SMILES ClCC1CO1
Properties
Chemical formula	C3H5ClO
Molar mass	92.52 g/mol
Density	1.1812 g/cm3
Melting point	-25.6 °C
Boiling point	117.9 °C
Hazards
NFPA 704 (fire diamond)	3 3 2
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) 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. 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:

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

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

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

In this way, more than 700,000 tons of epichlorohydrin are produced annually.

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, where Glycerol is a waste product, has led to a glut of glycerol on the market, rendering this process uneconomic for the mass market. Synthetic glycerol is now used only in sensitive pharmaceutical, technical and personal care applications where quality standards are very high. In fact, ways to perform the reverse process are now being researched, to produce epichlorohydrin from the now less valuable natural 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. 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.

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.

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

Safety

Epichlorohydrin is irritating and moderately toxic as well as carcinogenic.

See also

• Epoxy resins