64406-71-9Relevant academic research and scientific papers
A comprehensive mechanistic picture of the isomerizing alkoxycarbonylation of plant oils
Roesle, Philipp,Caporaso, Lucia,Schnitte, Manuel,Goldbach, Verena,Cavallo, Luigi,Mecking, Stefan
supporting information, p. 16871 - 16881 (2015/02/19)
Theoretical studies on the overall catalytic cycle of isomerizing alkoxycarbonylation reveal the steric congestion around the diphosphine coordinated Pd-center as decisive for selectivity and productivity. The energy profile of isomerization is flat with diphosphines of variable steric bulk, but the preference for the formation of the linear Pd-alkyl species is more pronounced with sterically demanding diphosphines. CO insertion is feasible and reversible for all Pd-alkyl species studied and only little affected by the diphosphine. The overall rate-limiting step associated with the highest energetic barrier is methanolysis of the Pd-acyl species. Considering methanolysis of the linear Pd-acyl species, whose energetic barrier is lowest within all the Pd-acyl species studied, the barrier is calculated to be lower for more congesting diphosphines. Calculations indicate that energy differences of methanolysis of the linear versus branched Pd-acyls are more pronounced for more bulky diphosphines, due to involvement of different numbers of methanol molecules in the transition state. Experimental studies under pressure reactor conditions showed a faster conversion of shorter chain olefin substrates, but virtually no effect of the double bond position within the substrate. Compared to higher olefins, ethylene carbonylation under identical conditions is much faster, likely due not just to the occurrence of reactive linear acyls exclusively but also to an intrinsically favorable insertion reactivity of the olefin. The alcoholysis reaction is slowed down for higher alcohols, evidenced by pressure reactor and NMR studies. Multiple unsaturated fatty acids were observed to form a terminal Pd-allyl species upon reaction with the catalytically active Pd-hydride species. This process and further carbonylation are slow compared to isomerizing methoxycarbonylation of monounsaturated fatty acids, but selective.
Oxidative degradation of the ascorbate anion in the presence of platinum and palladium. Formation and structures of platinum and palladium oxalate complexes
Arendse, Malcolm J.,Anderson, Gordon K.,Rath, Nigam P.
, p. 2495 - 2503 (2008/10/08)
The reactions of [Pt(NO3)2(dppm)] (dppm = bis(diphenylphosphino)methane) and cis-[Pt(NO3)2(PEt3)2] with sodium ascorbate are described. Complexes containing O,O-coordinated ascorbate ligand
Influence of ligands and anions on the rate of carbon monoxide insertion into palladium-methyl bonds in the complexes (P-P)Pd(CH3)Cl and [(P-P)Pd(CH3)(L)]+SO3CF3- (P-P = dppe, dppp, dppb, dppf; L = CH3CN, PPh3)
Dekker, Guido P. C. M.,Elsevier, Cornelis J.,Vrieze, Kees,Van Leeuwen, Piet W. N. M.
, p. 1598 - 1603 (2008/10/08)
The preparation of the neutral complexes (P-P)Pd(CH3)Cl (P-P = 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppb), 1,1′-bis-(diphenylphosphino)ferrocene (dppf)) and the ionic complexes [(P-P)Pd(CH3)(CH3CN)]+SO3CF 3- (P-P = dppe, dppp, dppb, dppf) is described. The ionic dppb complex was formed as a mixture of monomeric and oligomeric forms, which can be attributed to the length and the flexibility of the backbone of the ligand. The rate of CO insertion into the Pd-CH3 bond in these complexes has been studied. The rate was found to decrease in the order dppb ≈ = dppp > dppf for the neutral complexes with half-life times ranging from 18 to 36 min at 235 K and 25 bar of CO. The dppe complex reacted much slower with a half-life time of 170 min at 305 K. The rate of carbonylation of the Pd-CH3 bond in the cationic complexes was at least 10 times higher than those of the analogous neutral complexes, the order being dppb ≈ dppp ≈ dppf > dppe with half-life times a half-life time of 2.5 min was measured. Carbonylation of the ionic PPh3-coordinated complex [(dppp)Pd(CH3)(PPh3)]+-SO3CF 3- was at least 2.5 times slower than that of the analogous CH3CN-coordinated cationic complex.
