Metallo-Organic Compounds Containing Metal–nitrogen Bonds: Part Iii. Dialkylamino Compounds of Tantalum

Bradley, D. C.; Thomas, I. M.

doi:10.1139/v62-207

Cited by 98 publications

(63 citation statements)

References 3 publications

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“…All solvents were distilled and stored in a glove box under molecular sieves. Silicon tetraacetate, pentakis(dimethylamido)tantalum(V) and silver bis(dodecylamine) nitrate were prepared according to the literature [52][53][54], and stored in a glove box. Silicon tetrachloride (Acros Organics, Geel, Belgium, 99.8%), ethanol absolute (AnalaR NORMAPUR, Leuven, Belgium, 99.95%), silver nitrate (VWR, Leuven, Belgium, 99.9%), dodecylamine (VWR, Leuven, Belgium ≥97.0%), copper(II) acetylacetonate (TCI, Tokyo, Japan 97%), tantalum(V) ethoxide (ABCR, Karlsruhe, Germany, 99.99%) and acetonitrile (VWR, Leuven, Belgium, isocratic grade) were used as received.…”

Section: Catalyst Preparationmentioning

confidence: 99%

Ag- and Cu-Promoted Mesoporous Ta-SiO2 Catalysts Prepared by Non-Hydrolytic Sol-Gel for the Conversion of Ethanol to Butadiene

2019

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The direct catalytic conversion of bioethanol to butadiene, also known as the Lebedev process, is one of the most promising solution to replace the petro-based production of this important bulk chemical. Considering the intricate reaction mechanism—where a combination of acid-catalyzed dehydration reactions and metal-catalyzed dehydrogenation have to take place simultaneously—tailor-made bifunctional catalysts are required. We propose to use non-hydrolytic sol-gel (NHSG) chemistry to prepare mesoporous Ta-SiO2 materials which are further promoted by Ag via impregnation. An acetamide elimination route is presented, starting from silicon tetraacetate and pentakis(dimethylamido)tantalum(V), in the presence of a Pluronic surfactant. The catalysts display advantageous texture, with specific surface area in the 600–1000 m² g−1 range, large pore volume (0.6–1.0 mL g−1), an average pore diameter of 4 nm and only a small contribution from micropores. Using an array of characterization techniques, we show that NHSG allows achieving a high degree of dispersion of tantalum, mainly incorporated as single sites in the silica matrix. The presence of these monomeric TaOx active sites is responsible for the much higher dehydration ability, as compared to the corresponding catalyst prepared by impregnation of Ta onto a pristine silica support. We attempt to optimize the butadiene yield by changing the relative proportion of Ta and Ag and by tuning the space velocity. We also demonstrate that Ag or Cu can be introduced directly in one step, during the NHSG process. Copper doping is shown to be much more efficient than silver doping to guide the reaction towards the production of butadiene.

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Section: Catalyst Preparationmentioning

confidence: 99%

Ag- and Cu-Promoted Mesoporous Ta-SiO2 Catalysts Prepared by Non-Hydrolytic Sol-Gel for the Conversion of Ethanol to Butadiene

2019

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“…However, even after long reaction times, the products mixture consisted mainly of the unreacted starting materials. Therefore, we turned to the more traditional metal precursor, Ta(NMe 2 ) 5 [9]. As previously reported, the reaction of Ta(NMe 2 ) 5 with the less bulky ligand Lig 1 H 3 proceeded smoothly when the reagents were mixed in ether at RT, and after 2 h, no starting materials were detected in the reaction mixture [8b].…”

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confidence: 99%

Ta(V) complexes of a bulky amine tris(phenolate) ligand: steric inhibition vs. chelate effect

Groysman

Segal

Goldberg

et al. 2004

Inorganic Chemistry Communications

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“…Metal amides were prepared by known procedures (15)(16)(17)(18) and sodium cyclopentadienide was prepared by standard methods. 1,2-Dihydroxybenzene was obtained commercially and sublimed before use.…”

Section: Methodsmentioning

confidence: 99%

Complexes of the Early Transition Metals with o-Mercaptophenol and 1,2-Dihydroxybenzene

Martin¹,

Takats²

1975

Can. J. Chem.

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TAKATS. Can. J. Chem. 53,572 (1975). A novel synthetic approach, based on the reactivity of amido derivatives of the transition metals, M(NR,),,, towards protic reagents, for the synthesis of complexes of Ti, Zr, Hf, N b , and Ta with o-mercaptophenol and 1,2dihydroxybenzene is reported. The complexes, isolated as their tetraalkylammonium and tetraphenylarsonium salts, are moderately air stable, well behaved 2:l (Ti, Zr, HQ and 1:l (Nb, Ta) electrolytes. The u.v.-visible spectraof the complexes, which are somewhat reminiscent of the corresponding benzene-1,2dithiolates, are dominated by ligand-to-metal charge transfer bands. The band positions change in the expected manner, hypsochromic shifts in the order C,H4S2z-

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Metallo-Organic Compounds Containing Metal–nitrogen Bonds: Part Iii. Dialkylamino Compounds of Tantalum

Cited by 98 publications

References 3 publications

Ag- and Cu-Promoted Mesoporous Ta-SiO2 Catalysts Prepared by Non-Hydrolytic Sol-Gel for the Conversion of Ethanol to Butadiene

Ag- and Cu-Promoted Mesoporous Ta-SiO2 Catalysts Prepared by Non-Hydrolytic Sol-Gel for the Conversion of Ethanol to Butadiene

Ta(V) complexes of a bulky amine tris(phenolate) ligand: steric inhibition vs. chelate effect

Complexes of the Early Transition Metals with o-Mercaptophenol and 1,2-Dihydroxybenzene

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