A Cu/Cu2O@C composite catalyst derived from wood-chips for the efficient one-pot oxidation of cyclohexane to adipic acid

Adipic acid is widely used in fine chemical synthesis, biomedicine and other industrial fields, and is a key monomer for the synthesis of nylon-6,6 and nylon-6. Industrially, it is produced by the efficient catalytic oxidation of cyclohexane. However, the activation of the inert C―H bonds in cyclohexane remains a major challenge in the highly selective synthesis of acid products. Using a composite catalyst of copper on a carbon support produced from wood chip biomass, a green catalytic system was established for the one-pot oxidative synthesis of adipic acid from cyclohexane. Wood chips has two functions during pyrolysis: it acts as a carbon support precursor and an in-situ reducing agent, which reduces Cu 2+ into Cu/Cu 2 O active species to obtain Cu/Cu 2 O@C composite catalysts. The abundant defects in biomass carbon form strong coordination interactions with the copper active components, which effectively regulate the electronic distribution of active sites and improve the catalytic performance. Under optimized conditions (100 °C, 12 h), the Cu/Cu 2 O@C-0.1 catalyst achieves a cyclohexane conversion of 19.36% and an adipic acid selectivity of 73.28%. Mechanistic investigations show that the electronic interaction between the biomass carbon support and the copper species strengthens the adsorption of cyclohexanone, which is critical for promoting the selective formation of adipic acid. This study provides a viable strategy for developing eco-friendly, low-cost and high-efficiency advanced catalytic materials. Download: Download high-res image (138KB) Download: Download full-size image