A Cu/Cu2O@C Composite Catalyst Derived from Wood-Chips for the Efficient One-Pot Oxidation of Cyclohexane to Adipic Acid
Adipic acid is a key monomer for nylon-6,6 and nylon-6, yet its industrial production via nitric acid oxidation of KA oil suffers from high energy consumption and N2O emissions. This study reports a green catalytic system for one-pot oxidation of cyclohexane to adipic acid using a Cu/Cu2O@C composite catalyst derived from wood chips. During pyrolysis, wood chips serve as both carbon support precursor and in-situ reducing agent, converting Cu2+ into Cu/Cu2O active species. The abundant defects in biomass carbon form strong coordination interactions with copper, regulating the electronic distribution of active sites and enhancing catalytic performance. Under optimized conditions (100 °C, 12 h), the Cu/[email protected] catalyst achieves a cyclohexane conversion of 19.36% and an adipic acid selectivity of 73.28%. Mechanistic studies reveal that the electronic interaction between the carbon support and copper species strengthens adsorption of cyclohexanone, promoting selective formation of adipic acid. The reaction follows a free radical chain mechanism involving hydroxyl and alkyl radicals. This work provides a viable strategy for developing eco-friendly, low-cost, and high-efficiency catalytic materials for industrial adipic acid synthesis.