N-Doped Porous Carbon-Supported Cobalt Nanostructured Catalyst Derived from a Co-MOF for the Selective Ammoxidation of Alcohols

Abstract We report the synthesis of a nanostructured nitrogen-doped porous carbon-supported cobalt catalyst (Co-NC-600) via direct carbonization of a cobalt-based metal-organic framework [Co(1,4-bdc)(adenine)] under an inert atmosphere, and its application in the selective ammoxidation of primary alcohols to nitriles. The Co-NC-600 nanomaterial features uniformly dispersed cobalt nanoparticles (crystallite size: 9.85 nm) encapsulated within a graphitic nitrogen-doped porous carbon matrix (BET surface area: 209 m2 g–1), which stabilizes the active cobalt sites, facilitates substrate and oxygen transport, and imparts strong electronic synergistic effects. Under mild green conditions (water as solvent, O2 at 1 bar, 50 °C, 5 mg catalyst), Co-NC-600 converts benzylic, allylic, heterocyclic, vinylic, and aliphatic primary alcohols to the corresponding nitriles in excellent isolated yields (84 to 99%) within 6 h. The catalyst delivers a TOF of 3.3 h–1 with the lowest E-factor (0.059) among the compared systems and demonstrates gram-scale applicability (92% yield for Dichlobenil). Kinetic studies establish alcohol oxidation to the aldehyde as the turnover-limiting step and superoxide radicals (•O2–) as the primary reactive species. The nanostructured catalyst retains its structural integrity and catalytic performance over eight consecutive recycling runs, confirming the robustness conferred by the protective carbon nanoshell around the cobalt nanoparticles.