Immobilization of dihydrogen phosphate onto rice husk ash as a highly efficient and green catalyst for the synthesis of symmetrical N,N′-alkylidene bisamides

The preparation and characterization of an environmentally-benign and low-cost catalyst consisting of KH2PO4 supported on silica from rice husk ash is reported. The prepared catalyst was characterized by FT-IR spectroscopy, field emission scanning electron microscopy, powder X-ray diffraction and inductively coupled plasma. The synthesized nanocomposite exhibited an excellent catalytic efficiency in the condensation reaction for the preparation of symmetrical N,N′-alkylidene bisamides under solvent-free conditions.