ChemInform Abstract: IN SITU IR SPECTROSCOPIC STUDIES OF THE COBALT CARBONYL/TRI‐N‐BUTYLPHOSPHINE HYDROFORMYLATION CATALYST PART 2

Boven, Maurits Van; Alemdaroglu, N. H.; Penninger, J. M. L.

doi:10.1002/chin.197514042

Cited by 5 publications

(6 citation statements)

References 1 publication

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“…28. This spectrum is very similar to that observed in heptane solution [283] and it is close to that obtained on porous silica [284]. The observed deviations can be attributed to differences in the substrate effect and the different degree of the isomerization process.…”

Section: Formation and Stabilization Of Cosupporting

confidence: 70%

Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

Kukovecz

Kordás

Kiss

2016

Surface Science Reports

104

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Titanates are salts of polytitanic acid that can be synthesized as nanostructures in a great variety concerning crystallinity, morphology, size, metal content and surface chemistry.Titanate nanotubes (open-ended hollow cylinders measuring up to 200 nm in length and 15 nm in outer diameter) and nanowires (solid, elongated rectangular blocks with length up to 1500 nm and 30-60 nm diameter) are the most widespread representatives of the titanate nanomaterial family. This review covers the properties and applications of these two materials from the surface science point of view. Dielectric, vibrational, electron and X-ray spectroscopic results are comprehensively discussed first, then surface modification methods including covalent functionalization, ion exchange and metal loading are covered. The versatile surface chemistry of onedimensional titanates renders them excellent candidates for heterogeneous catalytic, photocatalytic, photovoltaic and energy storage applications, therefore, these fields are also reviewed.

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Section: Formation and Stabilization Of Cosupporting

confidence: 70%

Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

Kukovecz

Kordás

Kiss

2016

Surface Science Reports

104

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“…This spectrum is very similar to that observed in heptane solution 43 and it is close to that obtained on porous silica. 44 The observed deviations can be attributed to differences in the substrate effect and the different degrees of the isomerization process. Two strong bands were observed at 1986 and 2036 cm À1 and weak and broad bands were detected at 1928 and 1872 cm À1 , respectively.…”

Section: Resultsmentioning

confidence: 99%

Metal loading determines the stabilization pathway for Co2+ in titanate nanowires: ion exchange vs. cluster formation

Madarász

Pótári

Sápi

et al. 2013

Phys. Chem. Chem. Phys.

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Co nanoparticles were produced and characterized on protonated titanate nanowires. Co deposits were obtained after low-temperature decomposition of Co2(CO)8 on titanate nanostructures. The carbonylation was carried out by vapor-phase adsorption in a fluidized bed reactor and the decarbonylation processes were followed by FT-IR spectroscopy and microbalance combined with temperature programmed reaction mass spectrometry. The band gap of Co-decorated titanate nanostructures determined by UV-VIS diffuse reflectance spectroscopy decreased sharply from 3.14 eV to 2.41 eV with increasing Co content up to 2 wt%. The Co-decorated titanate morphology was characterized by high-resolution transmission electron microscopy (HRTEM) and electron diffraction (ED). The chemical environment of Co deposition was studied by photoelectron spectroscopy (XPS). A certain amount of cobalt underwent an ion exchange process. Higher cobalt loadings led to the formation of nanosized-dispersed particles complexed to oxygen vacancies. The average sizes were found to be mostly between 2 and 6 nm. This size distribution and the measured band gap could be favorable regimes for some important low-temperature thermal- and photo-induced catalytic reactions.

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“…48 High-pressure IR investigations have suggested that the phosphine ligand is displaced by CO according to the equilibrium in eq 5. [49][50][51][52] In contrast to the IR investigations, the in situ NMR method found no detectable amount of Co 2 (CO) 7 (Bu 3 P) formation under steady-state conditions with its unique chemical shift of 56.0 ppm even at 350 atm of CO pressure unless the Co/L ratio was less than unity. 7 The Co 2 (CO) 7 (n-Bu 3 P) complex is, however, observed as a transient species when the temperature is changed, as described in more detail in the Supporting Information.…”

Section: Resultsmentioning

confidence: 99%

Effect of Phosphines on the Thermodynamics of the Cobalt-Catalyzed Hydroformylation System

et al. 2006

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Thermodynamic parameters relevant to the phosphine-modified cobalt hydroformylation reaction are reported. Equilibrium constants for the hydrogenation of Co 2 (CO) 6 L 2 to yield HCo(CO) 3 L were determined using in situ 1 H and 31 P NMR spectroscopy between 75 and 175 °C for various solvents and phosphine ligands. Special emphasis was placed on n-Bu 3 P, as this ligand is prototypical of the Shell hydroformylation process. The resultant van't Hoff plots yield the enthalpy and entropy change (∆H ) 7.0 ( 0.4 kcal/mol and ∆S ) 2 ( 1 cal/mol•K) for the case of L ) n-Bu 3 P in benzene solvent. These parameters were found to be relatively insensitive to changes in the solvent, suggesting that the hydride product is not very polar. Even for isobutyl alcohol solvent, the resultant enthalpy and entropy changes (∆H ) 5.8 ( 0.4 kcal/mol and ∆S ) -2 ( 1 cal/mol•K) were found to be similar to those obtained in benzene and dioxane. Analysis of the 31 P NMR line widths allows rigorous lower limits to be established for the catalytically relevant Co-Co and Co-H bond energies in the case of L ) n-Bu 3 P (Co-Co g 23 kcal/mol and Co-H g 60 kcal/mol) relative to the previously reported values for the case of L ) CO (Co-Co ) 19 ( 2 kcal/mol and Co-H ) 59 ( 1 kcal/mol).

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ChemInform Abstract: IN SITU IR SPECTROSCOPIC STUDIES OF THE COBALT CARBONYL/TRI‐N‐BUTYLPHOSPHINE HYDROFORMYLATION CATALYST PART 2

Cited by 5 publications

References 1 publication

Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

Metal loading determines the stabilization pathway for Co2+ in titanate nanowires: ion exchange vs. cluster formation

Effect of Phosphines on the Thermodynamics of the Cobalt-Catalyzed Hydroformylation System

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