Green mussel shell-derived hydroxyapatite-CoFe₂O₄ catalyst: Microwave-assisted synthesis of 2-amino-4H-chromene derivative

The utilization of catalysts in organic reactions represents a widely utilized principle within the concept of green chemistry. This study focuses on utilizing hydroxyapatite from green mussel shell waste combined with CoFe₂O₄ as a heterogeneous catalyst for synthesizing 2-amino-4H-chromene derivative. The green mussel shells were calcined to produce CaO, which was then utilized as a precursor in the synthesis of hydroxyapatite, and then combined with cobalt ferrite through the coprecipitation method. Diffractogram analysis confirmed successful formation of hydroxyapatite, CoFe₂O₄, and their composite, validated against JCPDS data. Morphological analysis revealed irregular shapes, while magnetic property analysis indicated a slight decrease in the hydroxyapatite-CoFe₂O₄ composite compared to pristine CoFe₂O₄. Catalytic activity assessment demonstrated high yields (up to 88 %) under optimized conditions: catalyst concentration of 7.5 % w/w, reaction time of 15 minutes, in ethanol solvent, and using 300 Watts microwave power. The reusability of hydroxyapatite-CoFe₂O₄ as a catalyst, supported by the XRD and FTIR analyses, demonstrates its structural and chemical stability after five catalytic cycles, showcasing its potential as an eco-friendly and efficient catalyst.