Melamine paraformaldehyde polymer as an excellent support for hydroformylations of various alkenes

Abstract

Aldehydes are a vital class of fine chemicals, widely utilized as intermediates in drug synthesis, as well as in the production of fragrances and flavors. In industrial settings, aldehydes are predominantly synthesized through hydroformylation reactions. Numerous phosphorus-containing homogeneous and heterogeneous ligands or supports have demonstrated catalytic activity in this process. In this study, we synthesized a rhodium-modified, melamine-paraformaldehyde polymer-based heterogeneous catalyst by condensation followed by a hydrothermal method. The amine groups in the polymer effectively anchored the rhodium, resulting in well-dispersed Rh nanoparticles on the PMF support. The absence of FTIR bands at 2053 and 2143 cm^-1 confirmed the dissociation of Rh-complex. The HR-TEM identified the presence of ultrasmall Rh nanoparticles ( Avg. 2.9 nm) on the polymer. The synthesized catalyst demonstrated excellent hydroformylation activity, achieving over 99% styrene conversion with 95% selectivity toward aldehyde products under optimized conditions and maintained performance over four cycles. Rh-PMF_H catalyst showed high TON and TOF- 12,302, 2,050 h^-1, respectively. In addition, the catalyst showed excellent activity for a broad substrate scope.