Paired interacting orbitals (PIO) study of molybdena-alumina system active in alkene metathesis

Handzlik, Jarosław; Shiga, Akinobu; Kondziołka, Joanna

doi:10.1016/j.molcata.2007.12.028

Cited by 8 publications

(3 citation statements)

References 25 publications

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“…41,53 Handzlik et al have explored the stability of metallacycles with mononuclear Mo centers on alumina. 19,54 Energies from 36 to 137 kJ mol À1 below that of the reactants were reported for a diverse set of metallacycles, including square pyramidal (SP) and TBP geometries with several different coordinations and locations on the (100) and (110) planes. Poater et al studied homogeneous olefin metathesis using a variety of transition metals (Mo, W, and Re) and ligand combinations.…”

Section: Resultsmentioning

confidence: 99%

“…The stability of metallacycles with respect to reactants has been reported in several studies, , including homogeneous catalytic systems. , Handzlik et al have explored the stability of metallacycles with mononuclear Mo centers on alumina. , Energies from 36 to 137 kJ mol –1 below that of the reactants were reported for a diverse set of metallacycles, including square pyramidal (SP) and TBP geometries with several different coordinations and locations on the (100) and (110) planes. Poater et al studied homogeneous olefin metathesis using a variety of transition metals (Mo, W, and Re) and ligand combinations. , Using the same ligands (NCH 3 , CHCH 3 , −CH 2 CH 3 , and −OSiH 3 ), the energy pathways for olefin metathesis were studied as a function of the TM.…”

Section: Resultsmentioning

confidence: 99%

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Alkane Metathesis by Tantalum Metal Hydride on Ferrierite: A Computational Study

Mazar

Al-Hashimi²,

Bhan

et al. 2011

J. Phys. Chem. C

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The full catalytic cycle for the self-metathesis of ethane was studied by density functional theory (DFT). The active site was a Tadihydride grafted on a Brønsted acid site [(tAlO) 2 Ta(H 2 )] of the internal pore surface of the FER zeolite. The transition state geometries and activation energies were determined through the nudged elastic band (NEB) method for each elementary step, and the complete cycle was found to be thermodynamically consistent. Investigated elementary steps include ethane CÀH σ-bond activation, ethylene desorption through R and β hydrogen elimination mechanisms, Ta-ethylcarbene formation, olefin metathesis, and hydrogenation of olefin metathesis products. For the activation of ethane, as compared to catalytic systems involving zeolitesupported Ga and Zn, a low barrier (∼64 kJ mol À1 ) was observed. In the olefin metathesis step, where Ta-ethylcarbene reacts with ethylene, it was found that the Ta-metallacyclobutane has a relatively high stability (∼143 kJ mol À1 ) as compared to similar metallacyclobutane species and that the forward decomposition of the Ta-metallacyclobutane is the most energetically demanding step.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Alkane Metathesis by Tantalum Metal Hydride on Ferrierite: A Computational Study

Mazar

Al-Hashimi²,

Bhan

et al. 2011

J. Phys. Chem. C

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“…Al 2 O 3 -supported MoO 3 catalysts have been widely used in a number of catalytic reactions such as hydrogenolysis and hydrodesulfurization of crude oil [1], benzene hydrogenation [2], alkene metathesis reactions [3], and oxidative dehydrogenation of alkanes [4]. The structures of the supported Mo have been extensively investigated utilizing a variety of structural characterization techniques [1,[5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Catalytic dehydrogenation of cyclohexene over MoO3/γ-Al2O3 catalysts

Kady

Shaban

Naga

2011

Transition Met Chem

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A series of MoO 3 /c-Al 2 O 3 catalysts with different Mo surface densities (Mo atoms/nm 2 ) has been prepared by incipient wetness impregnation method. Structural characteristics of the prepared catalysts were investigated by atomic absorption spectroscopy, X-ray diffraction, Fourier Transform Infrared spectroscopy, N 2 adsorption at -196°C, and temperature-programmed reduction (TPR). The catalytic activities of the prepared catalysts were tested by cyclohexene conversion between 200 and 400°C. XRD results indicated that molybdenum oxide species were dispersed as a monolayer on the support up to 4.04 Mo atoms/nm 2 , and the formation of crystalline MoO 3 was observed above this loading. FTIR and TPR results showed that molybdenum oxide species were present predominantly in tetrahedral form at lower loading, and polymeric octahedral forms were dominant at higher loading. Cyclohexene conversion reaction proceeded mainly through the simple dehydrogenation pathway in the studied temperature range 200-400°C and was found to be highly dependent on MoO 3 dispersion.

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Acid–base concerted mechanism in the dehydration of 1,4-butanediol over bixbyite rare earth oxide catalysts

Sato¹,

Sato²,

Yamada³

et al. 2014

Catalysis Today

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Paired interacting orbitals (PIO) study of molybdena-alumina system active in alkene metathesis

Cited by 8 publications

References 25 publications

Alkane Metathesis by Tantalum Metal Hydride on Ferrierite: A Computational Study

Alkane Metathesis by Tantalum Metal Hydride on Ferrierite: A Computational Study

Catalytic dehydrogenation of cyclohexene over MoO3/γ-Al2O3 catalysts

Acid–base concerted mechanism in the dehydration of 1,4-butanediol over bixbyite rare earth oxide catalysts

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