Rhenium as a Catalyst in Hydrocarbon Reforming Reactions

Blackham, Angus U.; Beishline, Robert R.; Merrill, L.S.

doi:10.1021/i360016a015

Cited by 7 publications

(7 citation statements)

References 2 publications

(2 reference statements)

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“…These findings imply that catalytic chemistry occurs during the MTO-TMA process, and in fact, rhenium compounds have been described for and used in hydrocarbon reforming, acting as catalysts for dehydrocyclization reactions. 32 Also, molecular rhenium(I) pincer catalysts show activity in hydrogen autotransfer and dehydrogenative coupling reactions, and rhenium has been discussed as a catalyst for C− H and C−C bond activations. 33,34 In this context, it must be mentioned that organorhenium oxide complexes, such as CH 3 ReO 3 and similar compounds like (CH 3 ) 3 ReO 2 , have been investigated in detail regarding their molecular chemistry and with respect to their application in catalysis of organic reactions.…”

Section: ■ Resultsmentioning

confidence: 99%

Formation of Unsaturated Hydrocarbons and Hydrogen: Surface Chemistry of Methyltrioxorhenium(VII) in ALD of Mixed-Metal Oxide Structures Comprising Re(III) Units

et al. 2019

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We present the full investigation of the atomic layer deposition (ALD) of a mixed rhenium–aluminum oxide, namely ReAl2O3CH3, a material with tunable resistance, comprising the building unit of conductive rhenium oxides, ReO x . The deposition, involving methyltrioxorhenium(VII) (MeReO3, MTO) and trimethylaluminum (TMA), was analyzed by employing complementary in situ diagnostic quartz-crystal microbalance (QCM), Fourier-transform infrared (FT-IR) spectroscopy, and quadrupole mass spectrometry (QMS) to explore and reveal the underlying growth mechanism of this material. A proposed mechanism includes reductive elimination steps, thereby creating a stable Re(III)-containing thin film, making this ALD process unique regarding its growth. In addition, as proven by QMS, the surface reactions include the formation of hydrogen and unsaturated hydrocarbons. From this straightforward process, an extraordinarily high growth rate of 4.5 Å cycle–1 at temperatures as low as 150 °C was obtained. This material was found to exhibit highly promising electrical properties in terms of low thermal coefficient of resistance (TCR) in combination with high resistivity. By blending thin films of ReAl2O3CH3 with additional layers (1, 2, or 3) of Al2O3, we were able to fine-tune the electrical resistivity in the range of 3.9 × 106–1.5 × 1011 Ω·cm. Simultaneously, the TCR was lowered to about −0.014 °C–1, making this material highly resistive over a broad temperature range and a promising candidate for advanced detector applications, e.g., multichannel plates (MCPs).

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Section: ■ Resultsmentioning

confidence: 99%

Formation of Unsaturated Hydrocarbons and Hydrogen: Surface Chemistry of Methyltrioxorhenium(VII) in ALD of Mixed-Metal Oxide Structures Comprising Re(III) Units

et al. 2019

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“…The catalysts bring about partial or complete hydrogenation of these groups without attack on carbon-halogen or carbon-sulfur bonds (7,74,18,19,52). Some typical reactions are shown in Table IV.…”

Section: Hydrogenationmentioning

confidence: 99%

“…Similarly, ethylenic, disulfide, and heterocyclic aromatic groups can be hydrogenated without cleavage of the carbon-sulfur bond (7,18,79,52). Three examples are shown in Table IV; perhaps the most noteworthy is the conversion of allyl phenyl sulfide to propyl phenyl sulfide.…”

Section: Hydrogenationmentioning

confidence: 99%

Advances in Rhenium Catalysts

Davenport¹,

Kollonitsch²,

Klein³

1968

Ind. Eng. Chem.

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“…High vacuum, thus low oxygen partial pressure, environments produced in TIMS systems are what enable the successful use of rhenium as a thermal ionization filament. Despite its susceptibility to oxidation and terrestrial scarcity, rhenium has remained an important material in the production of turbine blades [12], catalysts [13], and heating elements [14]; consequently, rhenium has been the subject of scientific investigations for many decades [15, 16, 17, 18, 19, 20, 21, 22, 23]. Despite these efforts, little is known about the chemical identities of species involved in catalytic [24] and surface ionization mechanisms [25, 26] due to the challenges associated with in-situ analysis.…”

Section: Introductionmentioning

confidence: 99%

Ambient aging of rhenium filaments used in thermal ionization mass spectrometry: Growth of oxo-rhenium crystallites and anti-aging strategies

Mannion

Wellons

Shick

et al. 2017

Heliyon

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Degassing is a common preparation technique for rhenium filaments used for thermal ionization mass spectrometric analysis of actinides, including plutonium. Although optimization studies regarding degassing conditions have been reported, little work has been done to characterize filament aging after degassing. In this study, the effects of filament aging after degassing were explored to determine a “shelf-life” for degassed rhenium filaments, and methods to limit filament aging were investigated. Zone-refined rhenium filaments were degassed by resistance heating under high vacuum before exposure to ambient atmosphere for up to 2 months. After degassing the nucleation and preferential growth of oxo-rhenium crystallites on the surface of polycrystalline rhenium filaments was observed by atomic force microscopy and scanning electron microscopy (SEM). Compositional analysis of the crystallites was conducted using SEM-Raman spectroscopy and SEM energy dispersive X-ray spectroscopy, and grain orientation at the metal surface was investigated by electron back-scatter diffraction mapping. Spectra collected by SEM-Raman suggest crystallites are composed primarily of perrhenic acid. The relative extent of growth and crystallite morphology were found to be grain dependent and affected by the dissolution of carbon into filaments during annealing (often referred to as carbonization or carburization). Crystallites were observed to nucleate in region specific modes and grow over time through transfer of material from the surface. Factors most likely to affect the rates of crystallite growth include rhenium substrate properties such as grain size, orientation, levels of dissolved carbon, and relative abundance of defect sites; as well as environmental factors such as length of exposure to oxygen and relative humidity. Thin (∼180 nm) hydrophobic films of poly(vinylbenzyl chloride) were found to slow the growth of oxo-rhenium crystallites on the filament surfaces and may serve as an alternative carbon source for filament carburization.

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Rhenium as a Catalyst in Hydrocarbon Reforming Reactions

Cited by 7 publications

References 2 publications

Formation of Unsaturated Hydrocarbons and Hydrogen: Surface Chemistry of Methyltrioxorhenium(VII) in ALD of Mixed-Metal Oxide Structures Comprising Re(III) Units

Formation of Unsaturated Hydrocarbons and Hydrogen: Surface Chemistry of Methyltrioxorhenium(VII) in ALD of Mixed-Metal Oxide Structures Comprising Re(III) Units

Advances in Rhenium Catalysts

Ambient aging of rhenium filaments used in thermal ionization mass spectrometry: Growth of oxo-rhenium crystallites and anti-aging strategies

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