X-Ray Diffraction and Magnetic Studies of Unreduced Ferric Oxide Fischer-Tropsch Catalysts1

1946 ◽  
Vol 68 (10) ◽  
pp. 1953-1956 ◽  
Author(s):  
L. J. E. Hofer ◽  
W. C. Peebles ◽  
W. E. Dieter
Keyword(s):  
Ferric Oxide ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
Fischer Tropsch ◽  
X Ray

scholarly journals In situ observation of phase changes of a silica-supported cobalt catalyst for the Fischer–Tropsch process by the development of a synchrotron-compatible in situ/operando powder X-ray diffraction cell

2018 ◽  
Vol 25 (6) ◽  
pp. 1673-1682 ◽  
Author(s):  
Adam S. Hoffman ◽  
Joseph A. Singh ◽  
Stacey F. Bent ◽  
Simon R. Bare
Keyword(s):  
High Pressure ◽  
Elevated Pressure ◽  
Phase Changes ◽  
In Situ Observation ◽  
X Ray Diffraction ◽  
Fischer Tropsch ◽  
X Ray ◽  
And Performance ◽  
Co Nanoparticles

In situ characterization of catalysts gives direct insight into the working state of the material. Here, the design and performance characteristics of a universal in situ synchrotron-compatible X-ray diffraction cell capable of operation at high temperature and high pressure, 1373 K, and 35 bar, respectively, are reported. Its performance is demonstrated by characterizing a cobalt-based catalyst used in a prototypical high-pressure catalytic reaction, the Fischer–Tropsch synthesis, using X-ray diffraction. Cobalt nanoparticles supported on silica were studied in situ during Fischer–Tropsch catalysis using syngas, H2 and CO, at 723 K and 20 bar. Post reaction, the Co nanoparticles were carburized at elevated pressure, demonstrating an increased rate of carburization compared with atmospheric studies.

In situ X-ray diffraction of Fischer-Tropsch catalysts—Effect of water on the reduction of cobalt oxides

2017 ◽  
Vol 546 ◽  
pp. 103-110 ◽  
Author(s):  
James Paterson ◽  
Mark Peacock ◽  
Ewen Ferguson ◽  
Manuel Ojeda ◽  
Jay Clarkson
Keyword(s):  
Cobalt Oxides ◽  
X Ray Diffraction ◽  
Fischer Tropsch ◽  
X Ray ◽  
Effect Of Water

X-ray diffraction and magnetic studies of altered ilmenite and pseudorutile

1980 ◽  
Vol 43 (329) ◽  
pp. 659-663 ◽  
Author(s):  
M. J. Wort ◽  
M. P. Jones
Keyword(s):  
Magnetic Susceptibility ◽  
Western Australia ◽  
Wide Distribution ◽  
Diffraction Spectrum ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
Subsequent Work ◽  
Secondary Alteration ◽  
X Ray ◽  
Magnetic Spin

SynopsisIT was not until 1966 that pseudorutile was first defined. Earlier, its X-ray diffraction spectrum had been confused with that of futile and, to a lesser degree, with those of hematite and ilmenite. Subsequent work has shown that pseudorutile has a world-wide distribution in detrital ilmenite-bearing heavy mineral deposits. The present work has confirmed its magnetic susceptibility and density. In addition pseudorutile is shown to be a magnetic spin glass with a peak susceptibility at 23 °K.Altered ilmenites, in which pseudorutile occurs as a secondary alteration product, display a range of chemical composition and magnetic susceptibility. The most highly magnetic fractions are not necessarily those containing the least-altered ilmenite, and in material from Capel, Western Australia, the most highly magnetic fractions were those containing grains of ferrimagnetic ferrian ilmenite.Quantitative X-ray diffraction has shown that West Australian altered ilmenite contains significant amounts of amorphous ilmenite, pseudorutile, and rutile. The magnetic susceptibility of paramagnetic fractions of altered ilmenite from Capel, Western Australia, can be calculated from normative compositions based on chemical analyses.

Two CoII coordination polymers of biphenyl-2,2′,5,5′-tetracarboxylic acid with flexible N-donor ligands: syntheses, structures and magnetic properties

2019 ◽  
Vol 75 (8) ◽  
pp. 1073-1083 ◽  
Author(s):  
Feng Su ◽  
Cheng-Yong Zhou ◽  
Lin-Tao Wu ◽  
Xi Wu ◽  
Jing Su ◽  
...  
Keyword(s):  
Coordination Polymers ◽  
Three Dimensional ◽  
Donor Ligands ◽  
Tetracarboxylic Acid ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
Orbital Contribution ◽  
X Ray ◽  
3D Network ◽  
Methyl Benzene

Two CoII-based coordination polymers, namely poly[(μ4-biphenyl-2,2′,5,5′-tetracarboxylato){μ2-1,3-bis[(1H-imidazol-1-yl)methyl]benzene}dicobalt(II)], [Co2(C16H6O8)(C14H14N4)2] n or [Co2(o,m-bpta)(1,3-bimb)2] n (I), and poly[[aqua(μ4-biphenyl-2,2′,5,5′-tetracarboxylato){1,4-bis[(1H-imidazol-1-yl)methyl]benzene}dicobalt(II)] dihydrate], {[Co2(C16H6O8)(C14H14N4)2(H2O)2]·4H2O} n or {[Co2(o,m-bpta)(1,4-bimb)2(H2O)2]·4H2O} n (II), were synthesized from a mixture of biphenyl-2,2′,5,5′-tetracarboxylic acid, i.e. [H4(o,m-bpta)], CoCl2·6H2O and N-donor ligands under solvothermal conditions. The complexes were characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction and powder X-ray diffraction analysis. The bridging (o,m-bpta)4− ligands combine with CoII ions in different μ4-coordination modes, leading to the formation of one-dimensional chains. The central CoII atoms display tetrahedral [CoN2O2] and octahedral [CoN2O4] geometries in I and II, respectively. The bis[(1H-imidazol-1-yl)methyl]benzene (bimb) ligands adopt trans or cis conformations to connect CoII ions, thus forming two three-dimensional (3D) networks. Complex I shows a (2,4)-connected 3D network with left- and right-handed helical chains constructed by (o,m-bpta)4− ligands. Complex II is a (4,4)-connected 3D novel network with ribbon-like chains formed by (o,m-bpta)4− linkers. Magnetic studies indicate an orbital contribution to the magnetic moment of I and II due to the longer Co...Co distances. An attempt has been made to fit the χM T results to the magnetic formulae for mononuclear CoII complexes, the fitting indicating the presence of weak antiferromagnetic interactions between the CoII ions.

Possible confusion between so-called ferrihydrites and hisingerites

Clay Minerals ◽  
1992 ◽  
Vol 27 (3) ◽  
pp. 373-378 ◽  
Author(s):  
V. C. Farmer
Keyword(s):  
Diffraction Pattern ◽  
Ferric Oxide ◽  
Iron Content ◽  
Soil Conditions ◽  
Hydrous Ferric Oxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Laboratory Synthesis

AbstractThe term ferrihydrite, originally defined as a poorly ordered hydrous ferric oxide exhibiting five or more distinctive X-ray diffraction maxima, has come to be extended to include species that exhibit only 4, 3 or 2 of these maxima. It is pointed out here that hisingerites may exhibit a similar 2-line diffraction pattern. The laboratory synthesis of hisingerites show that they can form under soil conditions. Acid oxalate buffer of pH 3, a reagent considered a fairly specific solvent for ferrihydrite, extracts the iron content of these synthetic hisingerites quantitatively.

Thermally stable coordination compounds intercalated in montmorillonite clay mineral

1992 ◽  
Vol 70 (7) ◽  
pp. 1927-1931 ◽  
Author(s):  
N. K. Labhsetwar ◽  
O. P. Shrivastava
Keyword(s):  
Clay Mineral ◽  
Coordination Compounds ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
Swelling Properties ◽  
X Ray ◽  
Good Thermal Stability ◽  
Intercalated Compounds ◽  
Layered Clay

Montmorillonite is a natural layered clay mineral having myriad applications due mainly to its remarkable ion exchange, intercalation, and swelling properties. It can act as a good host for several compounds. Two intercalated coordination compounds of Cu(II) and Ni(II) with 2,2′-bipyridyl have been prepared in the interlayer spaces of montmorillonite structure. They are characterized on the basis of elemental analysis, infrared spectroscopy, magnetic studies, and X-ray diffraction. Both compounds show similarity in their structure and properties with the respective normal complexes of similar composition. These compounds show good thermal stability. The present intercalated compounds might be useful for their nitrogen-immobilizing properties and high-temperature applications.

Magnetoelectric and magnetic studies of the Bi1–xCaxFeO3 multiferrioc system

2014 ◽  
Vol 92 (5) ◽  
pp. 389-394 ◽  
Author(s):  
S.F. Mansour ◽  
N.I. Abu-Elsaad ◽  
T.A. Elmosalami
Keyword(s):  
Room Temperature ◽  
Energy Levels ◽  
Resonance Field ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
X Ray ◽  
Transmission Electron ◽  
Spin Resonance ◽  
Particle Size And Shape ◽  
Combustion Technique

Bi1–xCaxFeO3 was prepared by the flash autocombustion combustion technique. X-ray diffraction analysis showed a Rhombohedrally distorted hexagonal perovskite structure with space group R3c. The particle size and shape were studied by transmission electron microscope. Magnetization studies at room temperature showed superparamagnetic behavior for the prepared nanoparticles. Magnetoelectric coefficient characterized as magnetic field – induced polarization was investigated. The Lande factor (g), resonance field (Br), relaxation time (τ), and the energy between two adjacent degenerate spin energy levels (ΔE) were estimated from the electron spin resonance spectra.

Complexes of Light Lanthanides with 3,4-Dimethoxybenzoic Acid

2000 ◽  
Vol 65 (2) ◽  
pp. 179-191 ◽  
Author(s):  
Wiesława Ferenc ◽  
Agnieszka Walków-Dziewulska
Keyword(s):  
Magnetic Moments ◽  
Intermediate Formation ◽  
Lanthanide Ions ◽  
Ligand Field ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
X Ray ◽  
Light Lanthanides ◽  
Polycrystalline Solids ◽  
Van Vleck

The complexes of light lanthanides with 3,4-dimethoxybenzoic acid, Ln(C9H9O4)3·4 H2O, where Ln = La(III), Ce(III), Pr(III), Nd(III), Sm(III), Eu(III) and Gd(III), have been synthesized as polycrystalline solids and characterized by elemental analysis, IR spectroscopy, thermogravimetric and magnetic studies and X-ray diffraction measurements. The complexes possess colours typical of Ln(III) ions (La, Ce, Eu, Gd white, Pr greenish, Nd violet and Sm cream). The carboxylate group in these complexes binds as a symmetrical, bidentate chelating ligand. On heating in air to 1 273 K the 3,4-dimethoxybenzoates of Ce(III), Pr(III), Sm(III), Eu(III) and Gd(III) first dehydrate to anhydrous salts that further decompose to oxides of the respective metals. The 3,4-dimethoxybenzoates of La(III) and Nd(III) decompose in three steps. Firstly, they dehydrate to anhydrous salts that further decompose to the oxides with the intermediate formation of oxycarbonates. The solubilities of the studied complexes in water at 293 K is in the order of 10-4-10-3 mol dm-3. Their magnetic moments were determined in the temperature range 77-298 K and found to obey the Curie-Weiss law. The values of μeff calculated for the all compounds (except that for Eu) are close to those obtained for Ln(III) by Hund and van Vleck. The results show that there is no influence of the ligand field on 4f electrons of the lanthanide ions in these polycrystalline compounds; 4f electrons probably do not participate in the formation of the Ln-O bonds.

Sign in / Sign up

Export Citation Format

Share Document