51673-64-4Relevant articles and documents
Fast and unprecedented chemoselective hydroformylation of acrylates with a fluoropolymer ligand in supercritical CO2
Hu, Yulai,Chen, Weiping,Banet Osuna, Anna M.,Iggo, Jon A.,Xiao, Jianliang
, p. 788 - 789 (2002)
A fluorous polymeric phosphine, when combined with supercritical CO2 (scCO2) and rhodium, effects fast and highly chemoselective hydroformylation of acrylates, one of the least reactive olefins in hydroformylation reactions.
Catalytic isomerization-hydroformylation of olefins by rhodium salicylaldimine pre-catalysts
Sekoto, Pamela N.,Magengenene, Tseliso M.,Matsinha, Leah C.,Tia, Richard,Darkwa, James,Makhubela, Banothile C. E.
, p. 8751 - 8762 (2020/06/08)
A series of new Schiff-base rhodium(i) water-soluble complexes (C1-C3), were prepared and characterized. These complexes served as catalyst precursors for the hydroformylation of 1-octene and resulted in excellent substrate conversions (>98%) with 100% chemoselectivities to aldehydes, under mild conditions. Notably, good regioselectivities towards branched aldehydes were observed clearly demonstrating the catalysts’ ability in thermodynamically favoured isomerization followed by hydroformylation (n/iso ratio ranging between 0.7-1.2). Interestingly, catalystC1uniquely promoted contra-thermodynamic isomerization of 2-octene to 1-octene with up to 50% conversion. The efficacy of catalystC1was further evaluated in the hydroformylation of longer chain olefins (C10-C12), methyl acrylate, ethyl acrylate and styrene. The catalyst displayed conversions >99% with the long chain substrates and much lower conversions with the acrylates. These water-soluble (pre)catalysts were recycled up to three times with no significant loss in catalytic activity and selectivity. Mercury poisoning tests were conducted and the experiments revealed that the conversion of the substrates into aldehydes was due to molecular active catalysts and not as a result of colloidal particles that could have formedin situthrough the decomposition of the catalyst precursor. Finally, the molecular catalyst responsible for activity was established using preliminary computational calculations.
Hydroformylation of unsaturated esters and 2,3-dihydrofuran under solventless conditions at room temperature catalysed by rhodium: N-pyrrolyl phosphine catalysts
Alsalahi,Trzeciak
, p. 16990 - 16999 (2019/11/14)
Rhodium complexes of the type HRh(CO)L3 (where L is an N-pyrrolyl phosphine, such as P(NC4H4)3, PPh(NC4H4)2, or PPh2(NC4H4)) were applied in the hydroformylation of less reactive unsaturated substrates, namely allyl acetate, butyl acrylate, methyl acrylate, 2,3-dihydrofuran and vinyl acetate. Even at room temperature, these catalysts enabled complete substrate conversion and high chemoselectivity towards the corresponding aldehydes. High conversion of vinyl acetate (88% in 6 h) to the branched aldehyde was obtained with HRh(CO)[P(NC4H4)3]3 at 25 °C. An increase of the turnover frequency, TOF, up to 2000 mol mol-1 h-1 was achieved in this reaction under 20 bar of syngas (H2/CO = 1) at 80 °C. The introduction of chiral phosphines, BINAP or Ph-BPE, to this system resulted in the production of a branched aldehyde with enantioselectivity, ee, up to 44 and 81%, respectively. High activity combined with high enantioselectivity was achieved due to the formation of the mixed rhodium hydrides HRh(CO)[P(NC4H4)3](BINAP) and HRh(CO)[P(NC4H4)3](Ph-BPE), identified by the NMR method.
