High‐efficiency catalyst for copper nanoparticles attached to porous nitrogen‐doped carbon materials: Applied to the coupling reaction of alkyne groups under mild conditions

Supported catalysts have attracted extensive attention due to their excellent catalytic performance and reliability in heterogeneous catalysis. In this work, we report a general synthesis strategy that achieves the self-coupling reaction of acetylene derivatives to 1,3-diyne efficiently under conditions of copper catalyst impregnated on the precursor formed by acetone and urea. The experiments were performed by screening the base, solvent, temperature, and so forth to determine the optimum reaction conditions and then characterization and analysis of the catalyst. The results demonstrate that the Cu/CuO@CN(8) exhibits extraordinary reactivity to the self-coupling reaction and achieves a high turnover frequency (TOF = 96.8). Typically, the conversion of phenylacetylene reaches 99.9% under the optimal reaction conditions of NaOH (2 mmol) and tert-butanol (2 ml) and O-2 (1 atm) at 60 degrees C for 1 h. Nevertheless, it is worth noting that Cu/CuO@CN(8) has a large specific surface area (626.07 m(2) g(-1)) and low metal loading (3.3%) measured by Brunauer Emmett-Teller (BET) and ICP-OES, respectively. Simultaneously, kinetics and mechanism are also discussed and analyzed, and the thermodynamic energy value is calculated as 22.74 kJ mol(-1). Besides, the optimum catalyst can be reused five times under optimal conditions without a significant decrease in reactivity.