KNO₃/ACE: A cost-effective material for synthesis of (2E,4E)-1,5-diphenylpenta-2,4-dien-1-one and (E)-3-phenyl-5-styryl-1H-pyrazole

Potassium nitrate impregnated on activated chicken eggshell (KNO₃/ACE) was successfully prepared, and then it was characterized by means of IR, XRD, FESEM and EDAX spectroscopy. The KNO3/ACE showed high activity for the synthesis of chalcone compound, (2E,4E)-1,5-diphenylpenta-2,4-dien-1-one (3) from the reaction between acetophenone (1) and cinnamaldehyde (2). The highest yield of compound 3 was achieved up to 93% after reaction at 60°C for 2 h in the presence of 15 wt% catalyst. Then, compound 3 was further treated with hydrazine hydrate (4) to produce (E)-3-phenyl-5-styryl-1H-pyrazole (5) up to 97% yield using the same optimized condition as in chalcone synthesis.