On the mechanism of the Co2(CO)8 catalyzed hydroformylation of olefins in hydrocarbon solvents. A high pressure UV and IR study

NMR Spectroscopy

“…As judged from the asymmetry of the small peak inFigure 3.2-24, the resonance might stem from both the normal and the is0 derivatives.Measurable quantities of C O~( C O )~~were not detected. The only species observed were C3H7C(0)Co(C0)4, Co2(C0)*, and HCO(CO)~, as is consistent with Mirbach's infrared study of the reaction in liquid methylcyclohexane solution[55].As shown inFigure 3.2-25, the cobalt complexes reach a nearly steady-state condition early in the hydroformylation, which persists during the 15 hour period that the alkene is still present at significant levels. During this period, Concentrations of catalytic intermediates during propylene hydroformylation in supercritical COz at 80°C.…”

“…A typical 59C0 NMR spectrum at 80°C and 22.2 bar is shown in Figure 3 HCO(CO)~ is held below its equilibrium value for the reaction in eq (3.2-1), which is only achieved after the alkene is fully consumed. The results for propylene hydroformylation in supercritical C 0 2 have been compared 1531 with those of Mirbach [55] for the reaction of I-octene in methylcyclohexane solution. Under comparable conditions, the steady-state concentrations of the intermediates do not differ greatly (i.e.…”

The Catalytic Binuclear Elimination Reaction: Importance of Non-linear Kinetic Effects and Increased Synthetic Efficiency

“…In particular, Whyman [35,36], Alemdaroglu et al [37] and Mirbach [38] conducted in situ spectroscopic analyses using high-pressure infrared spectroscopy. All groups observed the simultaneous presence of the mononuclear species HCo(CO) 4 and RCOCo(CO) 4 with simple alkenes (i.e.…”

Fast screening of homogeneous catalysis mechanisms using graph-driven searches and approximate quantum chemistry

“…The hydroformylation of ethene by the complex HCo(CO) 4 is well-studied from both experimental and computational viewpoints. 12,[40][41][42][43][44][45][46][47] As shown in Fig. 2, the accepted mechanism comprises six key steps, namely: (i) carbon monoxide dissociation from HCo(CO) 4 to form the catalytically active HCo(CO) 3 species, (ii) coordination of alkene, (iii) Alkene insertion into the Co-H bond to form a cobalt alkyl species, (iv) coordination of carbon monoxide, (v) Insertion of carbon monoxide into the Co−C bond, (vi) Oxidative addition of H 2 , and (vii) Reductive elimination of the aldehyde product and reformation of the active catalyst.…”

“…2, the accepted mechanism comprises six key steps, namely: (i) carbon monoxide dissociation from HCo(CO) 4 to form the catalytically active HCo(CO) 3 species, (ii) coordination of alkene, (iii) Alkene insertion into the Co-H bond to form a cobalt alkyl species, (iv) coordination of carbon monoxide, (v) Insertion of carbon monoxide into the Co−C bond, (vi) Oxidative addition of H 2 , and (vii) Reductive elimination of the aldehyde product and reformation of the active catalyst. The rate law of cobalt-catalyzed hydroformylation has ben studied experimentally, [43][44][45]47 where the necessity of the carbon monoxide dissociation step from HCo(CO) 4 is supported by the finding that reaction rate decreases as carbon monoxide partial pressure increases. In addition, Harvey et al have shown how steady-state approximations applied to a kinetic model of propene hydroformylation also support the experimental rate law and its inverse carbon monoxide pressure dependence.…”