1761. Caprolactam

Nomenclature

CAS number: 105-60-2
Hexahydro-2H-azepin-2-one; ε-caprolactam; 2-oxohexamethylenimine; 2-ketohexamethylenimine; aminocaproic lactam.
C6H11NO; mol wt 113.16.
C 63.68%, H 9.80%, N 12.38%, O 14.14%.

Description and references

Prepn: Wallach, Ann. 312, 187 (1900); 343, 43 (1905); Ruzicka et al., Helv. Chim. Acta 4, 477 (1921); Eck, Marvel, J. Biol. Chem. 106, 387 (1934); Marvel, Eck, Org. Synth. coll. vol. II, 371 (1943); Lazier, Rigby, US 2234566 (1941 to du Pont); Schlack, US 2249177 (1941 to I. G. Farben); DE 739953 (1943); DE 745224 (1943); P. Smith, J. Am. Chem. Soc. 70, 320 (1948); E. Schmitz et al., J. Prakt. Chem. 319, 274 (1977). Environmentally benign synthesis from cyclohexanone: J. M. Thomas, R. Raja, Proc. Natl. Acad. Sci. USA 102, 13732 (2005). Purification: Kampschmidt, US 2786052 (1957 to Stamicarbon N. V.). Stabilization with alkalies: Indest et al., US 2884414 (1959 to Vereinigte Glanzstoff-Fabriken). Toxicity study: H. F. Smyth et al., Am. Ind. Hyg. Assoc. J. 30, 470 (1969). Reviews: CIOS Repts. no. 22 and 31, File XXXIII/Synthetic Fiber Developments in Germany, parts I & II; K. Kahr et al. in Ullmanns Encyklop"adie der technischen Chemie vol. 9, E. Bartholome et al., Eds. (Verlag Chemie, Weinheim, 4th ed., 1975) pp 96-114.

Chemical structure

Properties

Hygroscopic leaflets from petr ether, mp 70°. d475 (liq) 1.02. bp50 180°; bp3 100°. Viscosity (78°): 9 cP. Flash pt, open cup: 257°F (125°C). Freely sol in water, methanol, ethanol, ether, tetrahydrofurfuryl alcohol, dimethylformamide. Also sol in chlorinated hydrocarbons, cyclohexene, petroleum fractions. A 70% aq soln has d425 1.05; nD31 1.4965; nD40 1.4935. LD50 orally in rats: 2.14 g/kg (Smyth).

Caution

Potential symptoms of overexposure are irritation of eyes, skin, respiratory system; epistaxis; dermatitis, skin sensitization; asthma; irritability, confusion, dizziness, headache; abdominal cramps, diarrhea, nausea, vomiting; liver and kidney injury. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 50.

Use

Manuf of synthetic fibers of the polyamide type (Perlon); solvent for high mol wt polymers; precursor of nylon-6, q.v.