Hierarchical Porous Phenolic Resin and Its Supported Pd-Catalyst for Suzuki-Miyaura Reactions in Water Medium

The motivation of this work is to build micro and mesopores within phenolic resins to extend their applications to the heterogeneous catalysis field. For this purpose, porous hyper-cross-linked phenolic resin (PFN-P) with Brunauer-Emmett-Teller (BET) surface area of 775 m(2) g(-1) is synthesized through one-step polycondensation from tri(4-formylphenyl)phosphine and 2,5-dihydroxy-1,4-benzoquinone, which simultaneously contains abundant hydroxyl and triphenylphosphine moieties in the network. The resultant palladium-coordinated Pd@PFN-P possesses hierarchical porous structure with pore sizes ranging from 1.3 to 42.6 nm. The good hydrophilicity and broad pore sizes are advantageous for the accessibility of reactants to the catalyzing sites in the water medium for Suzuki-Miyaura reactions. As a result, high conversions for reactions between various aryl halides and phenylboronic acid are achieved under both oxygen-free and aerobic conditions. Moreover, the reaction conversions are almost unchanged after repeatedly using Pd@PFN-P for five times, showing promising potential for application in heterogeneous catalysis.