FeNP-loaded coal-bearing kaolin catalysts for the direct esterification of benzoic acid with cyclic ether via C(sp3)-H bond activation

The abundant and inexpensive transition metal iron was loaded onto the abundant nonmetal minerals of coal-bearing kaolin (CK) to synthesize cost-effective iron nanoparticle (FeNP)-loaded kaolin heterogeneous catalysts. Various characterization techniques were performed, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The catalytic activity was screened for the direct esterification of benzoic acid with cyclic ether via activation of the C(sp(3))-H bond in a cross-dehydrogenative-coupling reaction, and the corresponding alpha-acyloxy ether products were obtained in good yield. Notably, the FeNP-loaded CK solid catalysts were relatively stable and could be reused at least five times while retaining good catalytic activity. [GRAPHICS] .