Electrocatalytic Synthesis of Nylon-6 Precursor at Almost 100 % Yield

Synthesis of cyclohexanone oxime via the cyclohexanone-hydroxylamine process is widespread in the caprolactam industry, which is an upstream industry for nylon-6 production. However, there are two shortcomings in this process, harsh reaction conditions and the potential danger posed by explosive hydroxylamine. In this study, we presented a direct electrosynthesis of cyclohexanone oxime using nitrogen oxides and cyclohexanone, which eliminated the usage of hydroxylamine and demonstrated a green production of caprolactam. With the Fe electrocatalysts, a production rate of 55.9 g h(-1) g(cat)(-1) can be achieved in a flow cell with almost 100 % yield of cyclohexanone oxime. The high efficiency was attributed to their ability of accumulating adsorbed hydroxylamine and cyclohexanone. This study provides a theoretical basis for electrocatalyst design for C-N coupling reactions and illuminates the tantalizing possibility to upgrade the caprolactam industry towards safety and sustainability.

Automated summary

The synthesis of cyclohexanone oxime using the cyclohexanone-hydroxylamine process is widely used in the caprolactam industry. However, this process has drawbacks such as harsh reaction conditions and the potential danger of explosive hydroxylamine. This study presents a direct electrosynthesis of cyclohexanone oxime using nitrogen oxides and cyclohexanone, eliminating the need for hydroxylamine and demonstrating a green production of caprolactam. The use of Fe electrocatalysts results in a high production rate and almost 100% yield of cyclohexanone oxime in a flow cell. This study provides a theoretical basis for electrocatalyst design and offers the potential to upgrade the caprolactam industry towards safety and sustainability.