Depolymerization of nylon 6 using subcritical water

Abstract

When nylon 6 is decomposed for 20 minutes at 350°C, and 16.5 MPa of saturated vapor pressure in subcritical water, the decomposition ratio of nylon 6 was 99.1% and the yields of £-caprolactam and e-aminocaproic acid were 69.2% and 13.4%, respectively. In subcritical water, the reversible reaction between e-caprolactam and e-aminocaproic acid occurs and their equilibrium molar ratio was about 10:1 at 300°C and with saturated vapor pressure. Furthermore, e-aminocaproic acid decomposed to a byproduct. The calculated reaction time dependences of the yields of e-caprolactam and e-aminocaproic acid and the amount of the remaining nylon 6 for the whole hydrolysis route in subcritical water, agreed well with the experimental data. ©2013, The Society of Polymer Science, Japan.