Caprolactam

Chemical formula: C6H11NO

Molar mass: 113.16 g•mol−1

Appearance: White solid

Density: 1.01 g/cm3

Melting point: 69.2 °C (156.6 °F; 342.3 K)

Boiling point: 270.8 °C (519.4 °F; 544.0 K) at 1013.25 hPa

Solubility in water: 866.89 g/L (22 °C)

Vapor pressure: 0.00000008 mmHg (20° C)[1]

Caprolactam was first described in the late 1800s when it was prepared by the cyclization of ε-aminocaproic acid, the product of the hydrolysis of caprolactam. Given the commercial significance of Nylon-6, many methods have been developed for the production of caprolactam.

Almost all caprolactam produced goes into the manufacture of Nylon-6. The conversion entails a ring-opening polymerization:

n (CH₂)₅C(O)NH → [(CH₂)₅C(O)NH]_n

Nylon-6 is widely used in fibers and plastics.

In situ anionic polymerization is employed for cast nylon production where conversion from ε-caprolactam to Nylon-6 takes place inside a mold. In conjunction with endless fiber processing the term thermoplastic resin transfer molding (T-RTM) is often used.