Zeolite entrapped rhodium carbonyl clusters as catalyst for liquid phase hydroformylation of olefins

Mantovani, E.; Palladino, N.; Zanobi, A.

doi:10.1016/0304-5102(78)80035-2

Cited by 71 publications

(25 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The shifts of the terminal and bridging CO bands observed in both Co 4 (CO) 12 and Co 6 (CO) 16 in NaY zeolite are similar to the shifts observed for metal carbonyls in solutions containing Lewis acids such as Al(C 2 H 5 ) 3 , which have been examined extensively . Similar shifts have been also observed for [Rh 6 (CO) 16 ] in NaY zeolite and attributed to the interaction of the oxygen atoms of the face-bridging CO ligands with the Lewis acid sites (Al 3+ ions) 4c. The basicity of the oxygen in CO ligands of metal carbonyl clusters depends on the CO coordination geometry; triply bridging CO ligands are more basic than doubly bridging CO ligands, which are significantly more basic than terminal CO ligands.…”

Section: Resultssupporting

confidence: 76%

“…Nanostructures dispersed in the molecular-scale cages of zeolites include metal, , metal carbonyl clusters [Fe, Rh, Pd, Os, Ir, and Pt], and metal oxides. , The metal−carbonyl clusters have been prepared in the zeolites cages, often by the use of “ship-in-a-bottle” synthesis technology. ,, The preparation of uniform, encapsulated nanoclusters, especially in the respect of a higher metal loading process is often difficult, as mixtures often form both inside and outside the cages. The activation of these clusters for catalytic reactions usually requires their decarbonylation to give nearly structurally uniform materials that offer the prospect of being size/shape selective catalysts. − However, during the decarbonylation, the metal often migrates out the zeolite pores to form crystallites on the external surface .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cobalt Clusters in NaY Zeolite Cages: Synthesis and Characterization

1996

View full text Add to dashboard Cite

The adsorption of Co 2 (CO) 8 onto dehydrated NaY powder under a N 2 atmosphere and into a tetrahydrofuran slurry of NaY under a CO/H 2 atmosphere predominately yielded supported Co 4 (CO) 12 and supported Co 6 -(CO) 16 , respectively. The molecular cobalt-carbonyl clusters and their decarbonylated products have been structurally characterized by in situ infrared, extended X-ray absorption fine structure (EXAFS), and diffuse reflectance spectroscopies and NO chemisorption. The infrared spectrum of the species assigned to Co 4 -(CO) 12 /NaY and Co 6 (CO) 16 /NaY is shifted significantly from that observed for externally supported species on NaY and that observed for clusters, in solution, which indicates that the cobalt carbonyl clusters occurring on the NaY are similar to those occurring in weakly basic solution. The carbonyl activity of Co 6 (CO) 16 in isotopic exchange with 13 CO(g) is lower than that of Co 4 (CO) 12 . EXAFS coordination numbers showed that the successively decarbonylated sample maintained its small cluster size, which depended on the temperatureprogrammed oxidation of the precursor. The results of the research provide further indications of the potential of zeolite cages as microreactors for the preparation of metal clusters with controlled nuclearites. IntroductionNanostructures dispersed in the molecular-scale cages of zeolites include metal, 1,2 metal carbonyl clusters [Fe, 3 Rh, 4 Pd, 5 Os, 6 Ir, 7 and Pt 8 ], and metal oxides. 9,10 The metal-carbonyl clusters have been prepared in the zeolites cages, often by the use of "ship-in-a-bottle" synthesis technology. 4,5,8 The preparation of uniform, encapsulated nanoclusters, especially in the respect of a higher metal loading process is often difficult, as mixtures often form both inside and outside the cages. The activation of these clusters for catalytic reactions usually requires their decarbonylation to give nearly structurally uniform materials that offer the prospect of being size/shape selective catalysts. 11-13 However, during the decarbonylation, the metal often migrates out the zeolite pores to form crystallites on the external surface. 14 Preparation of metal carbonyl clusters with uniform nuclearities in zeolites has not been well demonstrated. The decarbonylated metal clusters are not yet well characterized. Chini et al. 15 demonstrated that the synthesis of Co 4 (CO) 12 and [Co 6 (CO) 15 ] 2-could be accomplished by boiling Co 2 (CO) 8 with 2-propanol in vacuum at 323 K and by boiling Co 2 (CO) 8 with ethanol in vacuum at 333 K, respectively. On the basis of the synthesis of Rh 6 (CO) 16 4 and [Pt 12 (CO) 24 ] 2-8 inside NaY cages, we infer the intrazeolite enviroment acts as a "solidsolvent". This suggests that the intrazeolite Co 4 (CO) 12 /Co 6 -(CO) 16 could be analogously formed with homogeneous preparation. The goals of the research are characterization of the cobalt carbonyl species and their decarbonylated products by infrared, extended X-ray absorption fine structure (EXAFS), and UV/vis spectroscopies and NO chemisorpt...

show abstract

Section: Resultssupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Cobalt Clusters in NaY Zeolite Cages: Synthesis and Characterization

1996

View full text Add to dashboard Cite

show abstract

“…It has been known that rhodium is the most active catalyst for hydroformylation. Although the catalyst development for the gas-phase [1,2] and liquid-phase [3][4][5][6] hydroformylation has been performed, the additive effect of various components on heterogeneous Rh catalysts has been investigated [7][8][9][10][11][12][13][14][15]. It has been reported that the additives such as Fe, Zn promote the formation of alcohols in ethylene hydroformylation [1,8].…”

Section: Introductionmentioning

confidence: 98%

Promoting Effect of Mo on Alcohol Formation in Hydroformylation of Propylene and Ethylene on Mo-Rh/SiO2

et al. 2005

View full text Add to dashboard Cite

It is found that the addition of Mo to Rh/SiO 2 (Mo-Rh/SiO 2 ) promoted alcohol formation in hydroformylation of propylene and ethylene, at the same time it drastically enhanced the activity of hydroformylation and hydrogenation. It is suggested that H 2 adsorption sites, which are not inhibited by CO adsorption, are present on Mo-Rh/SiO 2 . The sites can cause high H 2 activation, and it can be related to the additive effect of Mo in hydroformylation reactions.

show abstract

“…It has been known that rhodium is most active catalyst for hydroformylation reaction. Although the catalyst development for the gas-phase [1,2] and liquid-phase [3][4][5][6] hydroformylation has been performed, the additive effect of various components on heterogeneous Rh catalysts has been investigated [7][8][9][10][11][12][13]. It has been reported that the additives such as Fe, Zn, and Mo promoted the formation of alcohol in ethylene hydroformylation [7][8][9].…”

Section: Introductionmentioning

confidence: 98%