Recycling nylon 6 carpet to caprolactam

The recycling of nylon 6 carpet via depolymerization provides the potential for an environmentally benign new process to produce world-class caprolact am. This article describes the depolymerization of nylon 6 carpet in the pr esence of steam under medium pressure (800-1500 kPa, 100-200 psig). A small laboratory apparatus was set up to demonstrate the feasibility of the sche me. A total of eight runs were carried out using similar to 180 g of pellit ized carpet and 2-6 g/min steam (at 101-1500 kPa, 0-200 psig, and 300-340 d egrees C). In our best run at 340 degrees C, 6 g/min of steam, and 1500 kPa (200 psig) for 3 h, we obtained a 95% yield of crude caprolactam. The lact am purity was 94.4%, resulting in an overall 89.7% yield of caprolactam. Th e laboratory data were used to construct a computer model of the process fo r both batch and continuous-flow stirred reactors.