Design of mesostructured H3PW12O40-silica materials with controllable ordered and disordered pore geometries and their application for the synthesis of diphenolic acid

Abstract

A series of mesostructured H₃PW₁₂O₄₀-silica materials were developed by using a single step co-condensation technique in the presence of nonionic oligomeric surfactant, C₁₈H₃₇(OCH₂CH₂)₁₀OH (C₁₈EO₁₀, Brij76). By tuning the composition ratios of the starting precursors (mainly the molar ratios of water to the other materials) and the preparation conditions, the materials exhibited ordered two-dimensional (2D) hexagonal p6mm, three-dimensional (3D) hexagonal P6₃/mmc, and 3D disordered sponge-like pore geometries, respectively. The materials possessed unique textural properties including very large BET surface area (590–1050 m² g⁻¹), very high porosity (0.4–1.3 cm³ g⁻¹), and well-distributed pore diameter (3.0–5.4 nm). As a novel type of reusable solid acid catalyst, as-prepared materials were applied for the synthesis of diphenolic acid (DPA) from biomass-derived platform molecule, levulinic acid (LA), under solvent-free condition, and special attention was paid to investigating the influences of the structural orderings, pore geometries, H₃PW₁₂O₄₀ loadings, and template removal methods on the reactivity and selectivity of H₃PW₁₂O₄₀-silica materials to the target reaction.