Caprolactone
Chemical compound
From Wikipedia, the free encyclopedia
ε-Caprolactone or simply caprolactone is a lactone (a cyclic ester) possessing a seven-membered ring. Its name is derived from caproic acid. This colorless liquid is miscible with most organic solvents and water. It was once produced on a large scale as a precursor to caprolactam.[3]
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| Names | |||
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| Preferred IUPAC name
Oxepan-2-one | |||
| Other names
Caprolactone ε-Caprolactone Hexano-6-lactone 6-Hexanolactone Hexan-6-olide 1-Oxa-2-oxocycloheptane | |||
| Identifiers | |||
3D model (JSmol) |
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| ChemSpider | |||
| ECHA InfoCard | 100.007.217 | ||
| KEGG | |||
PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |||
| C6H10O2 | |||
| Molar mass | 114.14 g/mol | ||
| Density | 1.030 g/cm3 | ||
| Melting point | −1 °C (30 °F; 272 K) | ||
| Boiling point | 241 °C (466 °F; 514 K)[1] | ||
| Miscible [2] | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Production and uses
Caprolactone is prepared industrially by Baeyer-Villiger oxidation of cyclohexanone with peracetic acid.
Caprolactone is a monomer used in the production of highly specialised polymers. Ring-opening polymerization, for example, gives polycaprolactone.[3] Another polymer is polyglecaprone, used as suture material in surgery.[4]
Reactions
Although no longer economical, caprolactone was once produced as a precursor to caprolactam. Caprolactone is treated with ammonia at elevated temperatures to give the lactam:
- (CH2)5CO2 + NH3 → (CH2)5C(O)NH + H2O
Carbonylation of caprolactone gives, after hydrolysis, pimelic acid. The lactone ring is easily opened with nucleophiles including alcohols and water to give polylactones and eventually the 6-hydroxyadipic acid.
Related compounds
Several other caprolactones are known, including α-, β-, γ-, and δ-caprolactones. All are chiral. (R)-γ-caprolactone is a component of floral scents and of the aromas of some fruits and vegetables,[5] and is also produced by the Khapra beetle as a pheromone.[6] δ-caprolactone is found in heated milk fat.[7]
An ether of caprolactone is used as a binder for AP/AN/Al rocket propellant HTCE: Hydroxy-Terminated Caprolactone Ether [8]