Promoting Effect of Metal Promoters on Fe(II)-Zn-Based Double Metal Cyanide Complex Catalysts for Biodiesel Synthesis

2011 ◽  
Vol 236-238 ◽  
pp. 3041-3045 ◽  
Author(s):  
Ling Mei Yang ◽  
Peng Mei Lv ◽  
Zhen Hong Yuan ◽  
Wen Luo ◽  
Zhong Ming Wang ◽  
...  
Keyword(s):  
Rare Earth ◽  
Transition Metal ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
Molecular Formula ◽  
Cyanide Complex ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Cyanide ◽  
Biodiesel Synthesis

Fe(II)-Zn-based double metal cyanide complex catalysts modified with rare earth metal or transition metal promoters(lanthanum, cerium, zirconium, manganese) for the production of biodiesel were prepared, and the effect of the addition of different metal promoters on the characteristics of the catalyst was studied by using X-ray diffraction (XRD), BET, ICP and Infrared techniques .The experiment results show that the Fe(II)-Zn-based catalyst promoted with 1 wt.% of La(NO3)3·nH2O exhibits the highest catalytic activity for the reaction, being as high as 99.3% of the yield of fatty acid methyl esters (FAME). Fe(II)-Zn-based catalysts have a tentative molecular formula: K2Zn3[Fe(CN)6]2·xH2O· (t-BuOH), where x=3-9 determined by using elemental analysis and ICP. It has been shown that the molecular formula of Fe(II)-Zn-based double metal cyanide complex catalysts did not change by adding 1 wt.% of rare earth metal or transition metal promoters. X-ray diffraction and BET results showed that Fe(II)-Zn-based catalysts with 1 wt.% of metal promoters salts exhibit smaller particle size, higher surface area than the Fe(II)-Zn catalyst ,which may be related to the higher activity of the catalysts.

X-Ray Diffraction Study of Rare Earth Epitaxial Structures Grown by MBE onto (111) GaAs

1989 ◽  
Vol 151 ◽  
Author(s):  
W. R. Bennett ◽  
R. F. C. Farrow ◽  
S. S. P. Parkin ◽  
E. E. Marinero
Keyword(s):  
Rare Earth ◽  
Molecular Beam Epitaxy ◽  
Rare Earth Metal ◽  
Molecular Beam ◽  
Earth Metal ◽  
Magnetic Ordering ◽  
Metal Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Strain Components

ABSTRACTWe report on the new epitaxial system LaF3/Er/Dy/Er/LaF3/GaAs (111) grown by molecular beam epitaxy. X-ray diffraction studies have been used to determine the epitaxial relationships between the rare earths, the LaF3 and the substrate. Further studies of symmetric and asymmetric reflections yielded the in-plane and perpendicular strain components of the rare earth layers. Such systems may be used to probe the effects of magnetoelastic interactions and dimensionality on magnetic ordering in rare earth metal films and multilayers.

Rows of corner- and face-sharing Mg4 tetrahedra arranged as hexagonal rod packing in the hexagonal Laves phases REMg2 and the rare earth-rich phases RE9CoMg4 (RE=Y, Dy-Tm, Lu)

2018 ◽  
Vol 233 (9-10) ◽  
pp. 607-613 ◽  
Author(s):  
Sebastian Stein ◽  
Rainer Pöttgen
Keyword(s):  
Rare Earth ◽  
Rare Earth Metal ◽  
Diffraction Data ◽  
Earth Metal ◽  
Structural Motif ◽  
Induction Melting ◽  
X Ray Diffraction ◽  
Laves Phases ◽  
X Ray ◽  
The Many

Abstract Six new rare earth metal-rich intermetallic compounds RE9CoMg4 with RE=Y, Dy, Ho, Er, Tm and Lu were synthesized by induction-melting the elements in sealed niobium ampoules followed by annealing in muffle furnaces. The structures of Y9CoMg4 and Tm8.56CoMg4.44 were refined from single-crystal X-ray diffraction data: P63/mmc, a=965.65(6), c=971.07(5) pm, wR2=0.0599, 614 F2 values, 20 variables for Y9CoMg4 and a=945.20(4), c=953.11(5) pm, wR2=0.0358, 585 F2 values, 21 variables for Tm8.56CoMg4.44 (a small homogeneity range results from Tm/Mg mixing). The RE9CoMg4 phases crystallize with a coloring variant of the aristotype Co2Al5. The striking structural motif is a hexagonal rod packing of rows of corner- and face-sharing tetrahedral Mg4 clusters with Mg–Mg distances ranging from 304 to 317 pm in Y9CoMg4. These rows are similar to the hexagonal Laves phases REMg2. The space between the rows is filled with rows of face-sharing Co@Y6 trigonal prisms (TP) and empty Y6 octahedra (O) in the sequence –TP–O–O–. The many isopointal coloring variants of the aristotype Co2Al5 are briefly discussed.

Charge-density waves in Er5Ir4Si10 type compounds

2002 ◽  
Vol 12 (9) ◽  
pp. 347-350
Author(s):  
S. van Smaalen ◽  
P. Daniels ◽  
F. Galli ◽  
R. Feyerherm ◽  
E. Dudzik ◽  
...  
Keyword(s):  
Rare Earth ◽  
Phase Transitions ◽  
Synchrotron Radiation ◽  
Charge Density ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
Charge Density Waves ◽  
X Ray Diffraction ◽  
X Ray ◽  
Single Transition

X-ray diffraction with synchrotron radiation has been used to study the phase transitions in compounds M5Ir4Si10 with M a rare-earth metal. For M = Er, Ho and Er0.84Lu0.16 phase transitions have been found towards a combined commensurate/incommensurate state, that locks into a commensurate state at lower temperatures. For M = Lu and Er0.66Lu0.34 there is a single transition towards a commensurate state. The results are interpreted in terms of commensurate structural transitions that induce incommensurate CDWs.

Two series of rare earth metal-rich ternary aluminium transition metallides – RE6Co2Al (RE=Sc, Y, Nd, Sm, Gd–Tm, Lu) and RE6Ni2.25Al0.75 (RE=Y, Gd–Tm, Lu)

2018 ◽  
Vol 73 (11) ◽  
pp. 927-942 ◽  
Author(s):  
Frank Stegemann ◽  
Oliver Janka
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Rare Earth Metal ◽  
Magnetic Measurements ◽  
Earth Metal ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Antiferromagnetic Ordering ◽  
Arc Melting

AbstractThe rare earth metal-rich cobalt and nickel aluminium compounds with the general compositions RE6Co2Al (RE=Sc, Y, Nd, Sm, Gd–Tm, Lu) and RE6Ni2.25Al0.75 (RE=Y, Gd–Tm, Lu) have been synthesised from the elements by arc-melting, followed by annealing. Single-crystal X-ray diffraction experiments on Y6Co2.02(1)Al0.98(1) (Ho6Co2Ga type; Immm; a=944.1(2), b=952.4(2), c=999.0(2) pm; wR2=0.0452, 1123 F2 values, 35 variables) and Y6Ni2.26(1)Al0.74(1) (Ho6Co2Ga type; Immm; a=938.30(5), b=959.45(5), c=996.05(6) pm; wR2=0.0499, 1131 F2 values, 35 variables) revealed that the compounds form solid solutions according to the general formula RE6(Co/Ni)2+xAl1−x with different homogeneity ranges. The compounds of the Ni series can be obtained in X-ray pure form only with the nominal composition RE6Ni2.25Al0.75. A significant increase of the U22 component of the anisotropic displacement parameters of the Co/Ni2 atoms (4g site) was observed that requires a description of the structure with a split-position model at RT. Further investigations by low temperature (90 K) single-crystal X-ray diffraction experiments of Y6Co2.02(1)Al0.98(1) showed a significant decrease of U22. Magnetic measurements were conducted on the X-ray pure members of the RE6Co2Al (RE=Y, Dy–Tm, Lu) series. Antiferromagnetic ordering was observed for the members with unpaired f electrons with Néel temperatures up to TN=48.0(1) K and two spin reorientations for Dy6Co2Al.

Versatility of cyclooctatetraenyl ligands in rare earth metal complexes of the [M2(COT)3(THF)2] (M = Y and La) type

2019 ◽  
Vol 48 (17) ◽  
pp. 5614-5620
Author(s):  
Joshua Greenough ◽  
Zheng Zhou ◽  
Zheng Wei ◽  
Marina A. Petrukhina
Keyword(s):  
Rare Earth ◽  
Metal Complexes ◽  
Diffraction Analysis ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Rare Earth Metal Complexes

Two new organometallic cyclooctatetraenyl complexes of the type [M2(COT)3(THF)2] (M = Y and La) have been prepared, using optimized synthetic procedures, and fully characterized by X-ray diffraction analysis, IR and 1H NMR spectroscopies.

Synthesis and structure determination of Ce6Cd23Te: a new chalcogen-containing member of theRE6Cd23T family (REis a rare-earth metal and T is a late group 14, 15 and 16 element)

2017 ◽  
Vol 73 (2) ◽  
pp. 121-125 ◽  
Author(s):  
Griffen Desroches ◽  
Svilen Bobev
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Valence Fluctuations ◽  
High Temperature Reaction ◽  
Pearson Symbol

The ternary phase hexacerium tricosacadmium telluride, Ce6Cd23Te, was synthesized by a high-temperature reaction of the elements in sealed Nb ampoules and was structurally characterized by powder and single-crystal X-ray diffraction. The structure, established from single-crystal X-ray diffraction methods, is isopointal with the Zr6Zn23Si structure type (Pearson symbolcF120, cubic space groupFm-3m), a filled version of the Th6Mn23structure with the same space group and Pearson symbolcF116. Though no Cd-containing rare-earth metal binaries are known to form with this structure, it appears that the addition of small amounts of ap-block element allows the formation of such interstitially stabilized ternary compounds. Temperature-dependent direct current (dc) magnetization measurements suggest local-moment magnetism arising from the Ce3+ground state, with possible valence fluctuations at low temperature, inferred from the deviations from the Curie–Weiss law.

X-ray diffraction and resistivity studies of REBa2Cu3Oσ+x (RE - Y or rare earth metal)

1989 ◽  
Vol 69 (2) ◽  
pp. 191-194 ◽  
Author(s):  
A. Winiarski ◽  
A. Winiarska ◽  
A. Chełkowski
Keyword(s):  
Rare Earth ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
X Ray Diffraction ◽  
X Ray

Synthesis and structure determination of seven ternary bismuthides: crystal chemistry of theRELi3Bi2family (RE= La–Nd, Sm, Gd, and Tb)

2015 ◽  
Vol 71 (10) ◽  
pp. 894-899 ◽  
Author(s):  
Jai Prakash ◽  
Marion C. Schäfer ◽  
Svilen Bobev
Keyword(s):  
Rare Earth ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
X Ray Diffraction ◽  
Zintl Phases ◽  
Tetrahedral Geometry ◽  
X Ray ◽  
Pearson Symbol ◽  
Cell Volumes

Zintl phases are renowned for their diverse crystal structures with rich structural chemistry and have recently exhibited some remarkable heat- and charge-transport properties. The ternary bismuthidesRELi3Bi2(RE= La–Nd, Sm, Gd, and Tb) (namely, lanthanum trilithium dibismuthide, LaLi3Bi2, cerium trilithium dibismuthide, CeLi3Bi2, praseodymium trilithium dibismuthide, PrLi3Bi2, neodymium trilithium dibismuthide, NdLi3Bi2, samarium trilithium dibismuthide, SmLi3Bi2, gadolinium trilithium dibismuthide, GdLi3Bi2, and terbium trilithium dibismuthide, TbLi3Bi2) were synthesized by high-temperature reactions of the elements in sealed Nb ampoules. Single-crystal X-ray diffraction analysis shows that all seven compounds are isostructural and crystallize in the LaLi3Sb2type structure in the trigonal space groupP\overline{3}m1 (Pearson symbolhP6). The unit-cell volumes decrease monotonically on moving from the La to the Tb compound, owing to the lanthanide contraction. The structure features a rare-earth metal atom and one Li atom in a nearly perfect octahedral coordination by six Bi atoms. The second crystallographically unique Li atom is surrounded by four Bi atoms in a slightly distorted tetrahedral geometry. The atomic arrangements are best described as layered structures consisting of two-dimensional layers of fused LiBi4tetrahedra and LiBi6octahedra, separated by rare-earth metal cations. As such, these compounds are expected to be valance-precise semiconductors, whose formulae can be represented as (RE3+)(Li1+)3(Bi3−)2.

Dicationic Methyl Complexes of the Rare-Earth Elements

2014 ◽  
Vol 69 (3) ◽  
pp. 327-331 ◽  
Author(s):  
Anja Nieland ◽  
Andreas Mix ◽  
Beate Neumann ◽  
Hans-Georg Stammler ◽  
Norbert W. Mitzel
Keyword(s):  
Rare Earth ◽  
Nmr Spectroscopy ◽  
Crown Ether ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Elemental Analyses ◽  
Rare Earth Metal Complexes ◽  
C Nmr

The reactions of Ln(AlMe4)3 (Ln=Ho, Tm) with the crown ether [12]crown-4 yield dicationic methyl rare-earth metal complexes [LnMe([12]crown-4)2][AlMe4]2 (Ln=Ho (1), Tm (2)). The reaction of La(AlMe4)3 with [18]crown-6 in thf affords [LaMe([18]crown-6)(thf)2][AlMe4]2 (3). The compounds have been characterized by X-ray diffraction, 1 and 3 additionally by elemental analyses as well as by 1H and 27Al, and 3 also by 13C NMR spectroscopy

scholarly journals Synthesis and crystallographic characterization of diphenylamide rare-earth metal complexes Ln(NPh2)3(THF)2 and [(Ph2N)2 Ln(μ-NPh2)]2

2020 ◽  
Vol 76 (9) ◽  
pp. 1447-1453
Author(s):  
Chad T. Palumbo ◽  
Christopher M. Kotyk ◽  
Joseph W. Ziller ◽  
William J. Evans
Keyword(s):  
Rare Earth ◽  
Coordination Chemistry ◽  
Structural Characterization ◽  
Rare Earth Metal ◽  
Hydrolysis Product ◽  
Earth Metal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rare Earth Metal Complexes

Studies of the coordination chemistry between the diphenylamide ligand, NPh2, and the smaller rare-earth Ln III ions, Ln = Y, Dy, and Er, led to the structural characterization by single-crystal X-ray diffraction crystallography of both solvated and unsolvated complexes, namely, tris(diphenylamido-κN)bis(tetrahydrofuran-κO)yttrium(III), Y(NPh2)3(THF)2 or [Y(C12H10N)3(C4H8O)2], 1-Y, and the erbium(III) (Er), 1-Er, analogue, and bis[μ-1κN:2(η6)-diphenylamido]bis[bis(diphenylamido-κN)yttrium(III)], [(Ph2N)2Y(μ-NPh2)]2 or [Y2(C12H10N)6], 2-Y, and the dysprosium(III) (Dy), 2-Dy, analogue. The THF ligands of 1-Er are modeled with disorder across two positions with occupancies of 0.627 (12):0.323 (12) and 0.633 (7):0.367 (7). Also structurally characterized was the tetrametallic ErIII bridging oxide hydrolysis product, bis(μ-diphenylamido-κ2 N:N)bis[μ-1κN:2(η6)-diphenylamido]tetrakis(diphenylamido-κN)di-μ3-oxido-tetraerbium(III) benzene disolvate, {[(Ph2N)Er(μ-NPh2)]4(μ-O)2}·(C6H6)2 or [Er4(C12H10N)8O2]·2C6H6, 3-Er. The 3-Er structure was refined as a three-component twin with occupancies 0.7375:0.2010:0.0615.

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