Mechanochemical Synthesis of Mesoporous Copper Oxide for the Oxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid.

Mesoporous copper oxide (CuO) fabricated via mechanochemical milling was employed as a robust catalyst for the efficient synthesis of 2,5-furandicarboxylic acid (FDCA) in a sodium hypochlorite (NaClO) oxidation system. We demonstrate that introducing cetyltrimethylammonium bromide (CTAB) in the mechanochemical synthesis process successfully creates mesoporosity, reduces the size of CuO nanoparticles, and modulates the ratio between surface oxygen vacancies (OV) and lattice oxygen (OL). Owing to its minimized particle size, enlarged pore volume, and elevated OV/OL ratio, the CuO@0.4 CTAB catalyst delivers exceptional catalytic activity and reusability toward 5-hydroxymethylfurfural (HMF) oxidation, affording a maximum FDCA yield of 95.2% under optimal reaction conditions. Furthermore, maintaining the solution pH value above 12 greatly inhibits the over-oxidation of FDCA and slows the rapid consumption of NaClO during the reaction.