Boosted hydroformylation of high-carbon olefins with optimized n/i ratio via monodisperse rhodium catalysts supported on copolymerized porous organic ligands

Abstract

Hydroformylation is a pivotal industrial homogeneous catalytic process, mainly relying on rhodium-based organophosphorus catalytic systems. However, this system faces critical challenges: cumbersome product separation, severe leaching of precious rhodium, and a low n/i (normal/iso-aldehyde) ratio of target products, hampering its industrial efficiency. Porous organic ligand polymers (POLs)—endowed with excellent thermal stability and hierarchical pores—are ideal heterogeneous supports for rhodium catalysts, effectively suppressing metal leaching and showing great potential in high-carbon olefin hydroformylation. Herein, we designed a xanthene-based oxygen-containing diphosphine ligand, which was copolymerized with vinyltriphenylphosphine to prepare porous organic copolymer supports with different monomer ratios. Using these supports, we successfully constructed a supported single-atom rhodium catalyst. Experimental results show that the catalyst exhibits excellent thermal stability and long-term durability, achieving high substrate conversion and remarkable n-aldehyde selectivity in the hydroformylation of high-carbon olefins (e.g., 1-octene). Characterization further reveals that the copolymerization-enabled precise regulation of the ligand microenvironment, combined with the xanthene-based diphosphine's modulation of the electronic state and spatial configuration of rhodium active centers, forms a synergistic effect—this is the key to the catalyst's significantly improved n/i ratio. This work addresses core limitations of traditional rhodium catalytic systems, offering a promising heterogeneous catalyst for efficient industrial hydroformylation of high-carbon olefins.