Palladium immobilized in the nanocages of SBA-16: An efficient and recyclable catalyst for Suzuki coupling reaction

Wang, Haibo; Zhang, Yaoheng; Yang, Honglei; Ma, Zongyan; Zhang, Fengwei; Sun, Jian; Ma, Jiantai

doi:10.1016/j.micromeso.2012.09.025

Cited by 29 publications

(7 citation statements)

References 52 publications

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“…The low angle XRD patterns of SBA-16 were displayed in Figure 2. The SBA-16 exhibits two diffraction (110) and (200) peaks, characteristic of mesoporous materials [44].…”

Section: Resultsmentioning

confidence: 99%

“…A blank experiment without phenol under the same experimental conditions produced an amount of cyclohexane (10–15 mol %). However, the use of benzene as solvent for phenol hydrogenation is preferred because under the adopted experimental conditions, the hydrogenation of phenol is predominant if compared to the hydrogenation of benzene, as reported in the literature [43,44,45,46,47,48,49]. A premixed phenol and benzene with a benzene/phenol molar ratio = 2 was fed into the pre-heater by means of a micro-feeder (liquid flow rate = 3 .…”

Section: Methodsmentioning

confidence: 99%

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Vapour Phase Hydrogenation of Phenol over Rhodium on SBA-15 and SBA-16

2014

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Abstract:In the present work, mesoporous SBA-15 and SBA-16 were synthesised using classical methods, and their physicochemical properties were investigated by X-ray diffraction (XRD), FTIR, TEM and N2 adsorption-desorption. Rhodium (Rh, 1 wt %) was loaded on the mesoporous SBA-15 and SBA-16 by an impregnation method. The Rh surface coverage, dispersion and crystallite size were determined by room temperature H2 chemisorption on reduced samples. The catalytic activity of Rh supported on mesoporous SBA-15 and SBA-16 was evaluated for the first time in the hydrogenation of phenol in vapour phase in a temperature range between 130 and 270 °C at atmospheric pressure. The reaction over Rh/SBA-15 at 180 °C produced cyclohexanone as the major product (about 60%) along with lower amounts of cyclohexanol (about 35%) and cyclohexane (about 15%). The influences of temperature, H2/phenol ratio, contact time and the nature of the solvent on the catalytic performance were systematically investigated. The Rh/SBA-16 system offered lower phenol conversion compared to Rh/SBA-15, but both have a very high selectivity for cyclohexanone (above 60%).

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“…The low angle XRD patterns of SBA-16 were displayed in Figure 2. The SBA-16 exhibits two diffraction (110) and (200) peaks, characteristic of mesoporous materials [44].…”

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Vapour Phase Hydrogenation of Phenol over Rhodium on SBA-15 and SBA-16

2014

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“…[9][10] Iron oxides particles have been paid growing attention owing to their unique properties and potential applications in various fields, such as magnetic resonance imaging (MRI) contrast agents 11 , magnetically assisted drug delivery 12 , hyperthermia 13 and recycling of catalysts. [4][5][6] Magnetite (Fe 3 O 4 ) is generally accepted as being appropriate and safe for in vivo biomedical applications, non-toxic, hydrophilic, and biocompatible, and they have to remain stable in aqueous colloidal suspensions. 14 However magnetic nanoparticles must be stabilized by protective agent against the tendency towards agglomeration.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3] These catalysts have been widely applied to some important reactions such as Suzuki and Heck couplings as well as oxidation of suldes and thiols. [4][5][6][7][8] Although many catalytic oxidation reactions using homogeneous catalysts have been successfully demonstrated, the difficulties in separating the catalysts greatly restrict their applications in practice. Heterogeneous catalysts usually need tedious procedures such as ltration and centrifugation for recycling aer reactions.…”

Section: Introductionmentioning

confidence: 99%

“…9,15,16 The Schiff base moiety is one of the preferred functional groups for anchoring different catalytic species on the magnetic nanoparticles. 4,19,20 In this study, new heterogeneous nanocatalysts were synthesized by the covalent anchoring of [MoO 2 Cl 2 (DMSO) 2 ] complex on the amino propyl and Schiff base coated magnetic nanoparticles as active, magnetically separable oxidation catalysts. Furthermore, the obtained catalysts showed not only high catalytic activity in oxidation reactions but also high degree of chemical stability in various organic solvents.…”

Section: Introductionmentioning

confidence: 99%

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Mo(vi) complex supported on Fe₃O₄ nanoparticles: magnetically separable nanocatalysts for selective oxidation of sulfides to sulfoxides

et al. 2015

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ARTICLE This journal isA molybdenum complex, [MoO 2 Cl 2 (DMSO) 2 ], was immobilized on amino propyl and Schiff base modified magnetic Fe 3 O 4 @SiO 2 nanoparticles by covalent linkage. The resulting nanoparticles were used as efficient and recyclable catalysts for the selective oxidation of sulfides to sulfoxides using urea hydrogen peroxide as the oxidant. The complete characterization of catalysts was carried out by means of thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), elemental analysis, FT-IR and Raman microprobe techniques.

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Why Does Industry Not Use Immobilized Transition Metal Complexes as Catalysts?

2015

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Much effort has gone into the immobilization of homogeneous catalysts based on the idea that in this way the catalysts could be not only separated more easily from the product but also reused several times, thus reducing the cost of the catalyst use. So far none of these immobilized catalysts have been used by industry. In this article we critically review the use of immobilized homogeneous catalysts from the point of view of process development for the pharmaceutical and fine chemical industry. The first and foremost question that needs to be answered is: will immobilizing a homogeneous catalyst really lead to lower costs? The answer is thus far always no. This is caused mostly by the fact that homogeneous catalysts are not stable and thus there is little point in immobilizing them. The second reason is the extra added cost that is incurred in immobilizing the catalysts. Other problems are lower rates, sometimes lower selectivities and metal leaching. Three different areas are discussed. The research on immobilized metathesis catalysts is analyzed in detail; in general the immobilized catalysts do not achieve sufficient turnovers to be interesting for industrial use. Very many publications have appeared on immobilized palladium catalysts that were used for CC bond‐forming reactions, such as Suzuki, Heck or Sonogashira reactions. These catalysts are invariably converted to nanoparticles after the first run. Although these catalysts can be reused, there is no reason to use an expensive support based on immobilized ligands. This also does not protect the product from palladium contamination. Even more effort has gone into the immobilization of homogeneous hydrogenation catalysts. Most of these catalysts suffer from the same problems as the other immobilized catalysts: catalyst deactivation, low turnover numbers, and leaching of the metal. In addition, the heterogenization adds complexity to the system, increasing risk and prolonging process development.magnified image

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Palladium immobilized in the nanocages of SBA-16: An efficient and recyclable catalyst for Suzuki coupling reaction

Cited by 29 publications

References 52 publications

Vapour Phase Hydrogenation of Phenol over Rhodium on SBA-15 and SBA-16

Vapour Phase Hydrogenation of Phenol over Rhodium on SBA-15 and SBA-16

Mo(vi) complex supported on Fe₃O₄ nanoparticles: magnetically separable nanocatalysts for selective oxidation of sulfides to sulfoxides

Why Does Industry Not Use Immobilized Transition Metal Complexes as Catalysts?

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Palladium immobilized in the nanocages of SBA-16: An efficient and recyclable catalyst for Suzuki coupling reaction

Cited by 29 publications

References 52 publications

Vapour Phase Hydrogenation of Phenol over Rhodium on SBA-15 and SBA-16

Vapour Phase Hydrogenation of Phenol over Rhodium on SBA-15 and SBA-16

Mo(vi) complex supported on Fe3O4 nanoparticles: magnetically separable nanocatalysts for selective oxidation of sulfides to sulfoxides

Why Does Industry Not Use Immobilized Transition Metal Complexes as Catalysts?

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Mo(vi) complex supported on Fe₃O₄ nanoparticles: magnetically separable nanocatalysts for selective oxidation of sulfides to sulfoxides