Ionic Liquid Templated Ordered Hexagonal Mesoporous Iron Phosphate Molecular Sieves: A Highly Effective Heterogeneous Catalysts with Remarkable Selectivity for Phenol Hydroxylation Reaction

Abstract

AbstractA highly organized hexagonal mesoporous iron phosphate framework structure with the designation HMI‐41 was successfully synthesized for the first‐time in a reproducible way using imidazolium‐based ionic liquid as structure directing agent. The unique templating properties of ionic liquid generated a highly ordered well‐crystallized mesoporous matrix having high surface area (445 m2 g−1), thicker pore wall (2.1 nm) and narrow pore size distribution (3.1 nm). The presence of active sites within a tetrahedral framework structure made the novel HMI‐41 catalyst highly effective for phenol hydroxylation in an acidic medium with hydrogen peroxide as the oxidant. The catalyst exhibited outstanding performance, achieving an impressive 80% hydroquinone selectivity and 21% phenol conversion with a hydroquinone‐to‐catechol ratio of seven, which is the highest value ever reported.