Abstract
Amide formation through the Ritter reaction remains a valuable transformation in pharmaceutical and materials chemistry, yet conventional protocols rely heavily on corrosive homogeneous acids and non-green conditions. In this study, a magnetite nanoparticles/graphitic carbon nitride/ nitrilotri(methylphosphonic acid (Fe(3)O(4)/g-C(3)N(4)/NTMPA) magnetic nanocomposite (MNC) was synthesized via a co-precipitation method and employed as an efficient and recyclable solid acid catalyst for solvent-free Ritter reactions at 80 °C. Structural and morphological analyses using FT-IR, XRD, FE-SEM, TEM, DLS, and EDX confirmed successful incorporation of NTMPA and uniform distribution of Fe, C, N, O, and P throughout the composite. BET analysis showed a surface area of 11.421 m(2)/g, pore volume of 0.0588 cm³/g, and mean pore diameter of 20.593 nm, indicating a mesoporous structure conducive to catalytic accessibility. TGA revealed a major decomposition step of 23.88% between 500 and 600 °C corresponding to g-C(3)N(4) degradation, confirming appropriate thermal stability. The catalyst demonstrated broad substrate applicability, converting tertiary alcohols and benzylic alcohols to the corresponding amides in high to excellent yields in 1.25-6 h. Aromatic nitriles consistently delivered yields above 90% within 5-6 h, with electron-withdrawing substituents further enhancing reactivity and aliphatic nitriles provide the related amides in 87-98% yields within 1.5-5.5 h. The catalyst retained over 90% activity after six cycles, with post-reaction analyses confirming structural integrity. These results highlight Fe(3)O(4)/g-C(3)N(4)/NTMPA as a robust, magnetically recoverable, and environmentally compatible catalyst for green amide synthesis.