Electrosynthesis of a nylon-6 precursor from cyclohexanone and nitrite under ambient conditions

Cyclohexanone oxime, an important nylon-6 precursor, is conventionally synthesized through cyclohexanone-hydroxylamine (NH2OH) and cyclohexanone ammoxidation methodologies. These strategies require complicated procedures, high temperatures, noble metal catalysts, and toxic SO2 or H2O2 usage. Here, we report a one-step electrochemical strategy to synthesize cyclohexanone oxime from nitrite (NO2-) and cyclohexanone under ambient conditions using a low-cost Cu-S catalyst, avoiding complex procedures, noble metal catalysts and H2SO4/H2O2 usage. This strategy produces 92% yield and 99% selectivity of cyclohexanone oxime, comparable to the industrial route. The reaction undergoes a NO2- → NH2OH→oxime reaction pathway. This electrocatalytic strategy is suitable for the production of other oximes, highlighting the methodology universality. The amplified electrolysis experiment and techno-economic analysis confirm its practical potential. This study opens a mild, economical, and sustainable way for the alternative production of cyclohexanone oxime.