A Porous Monophosphine Polymer-Supported Ruthenium-Catalysts for Aerobic Oxidation of Alcohols to Fatty Acids in Base-Free Aqueous Phase

Base-free aerobic oxidation of fatty alcohols serves as a sustainable approach toward high-value fatty acids, whereas efficient recyclable catalysts targeting fatty acids are still difficult to develop.Herein, we fabricate a monophosphine-functionalized hierarchically porous organic polymer immobilized Ru catalyst (Ru@POP-p-2vPPh 3 ) with evenly distributed Ru active sites. Under aqueous oxygen atmosphere at 140 ℃, diverse primary alcohols including odd and even fatty alcohols, haloalkyl, arylalkyl and cyclic benzylic alcohols are transformed into corresponding odd and even fatty acids with yields ranging from 48% to 90%. Systematic characterizations verify that Ru(II) species and phosphine ligands are in situ oxidized to high-valent Ru(III)/Ru(IV) and P(V) species to drive the reaction via a singleelectron-transfer radical pathway. A recombination recycling strategy combining recovered Ru solid catalyst and Ru-containing filtrate maintains roughly 80% yield across six consecutive cycles. This mild, eco-friendly base-free provides an alternative strategy for the convenient preparation of high-value fatty acids.