149095-10-3Relevant academic research and scientific papers
Effect of carboxylic acids on the yield and selectivity of the hydroformylation of hex-1-ene catalyzed by [Rh(acac)(CO)(PPh3)]
Mieczynska, E.,Trzeciak, A. M.,Ziolkowski, J. J.
, p. 189 - 200 (2008/10/08)
The effect of the carboxylic acids RCO2H (R=C2H5, C6H5, m-ClC6H4, p-NO2C6H4 and o-HOC6H4) on the hydroformylation of hex-1-ene catalyzed by Rh(acac) (CO) (PPh3) (1) have been studied. The decrease of the rate of hydroformylation compared with a carboxylic acid-free systems was observed. The inhibiting influence of carboxylic acids is stronger in reactions proceeding in the presence of free phosphine (e.g. (1)/]RCO2H + PPh3]) where not only the reaction rate, but also hex-1-ene conversion decrease. The inhibiting effect of carboxylic acids may be explained by partial elimination of catalytically active forms of the general formula HRh(CO)x(PPh3)y by the reaction of HRh(CO)x(PPh3)y in the presence of RCO2H/PPh3 and H2/CO to give Rh(RCO2) (CO) (PPh3)2. The equilibrium of this reaction depends mainly on the concentrations of the H+ ions and that of free phosphine. Several new rhodium complexes were formed in the reaction of (1) with RCO2H, e.g, [Rh(RCO2) (CO) (PPh3)]2, [Rh(RCO2) (CO)2 (PPh3], [Rh (RCO2) (CO) (PPh3)2], [Rh (RCO2) (CO)2]2, have been isolated and used as hydroformylation reaction catalysts. The structures of Rh(acac) (HOC6H4CO2) (PPh3) (H2O) and [Rh(HOC6H4CO2) (COD) ]2 have been determined by X-ray diffraction studies.
