Raman scattering study of Ge and Sn compounds with type-I clathrate hydrate crystal structure

2000 ◽  
Vol 62 (11) ◽  
pp. 7157-7161 ◽  
Author(s):  
G. S. Nolas ◽  
C. A. Kendziora
Keyword(s):  
Crystal Structure ◽  
Raman Scattering ◽  
Clathrate Hydrate ◽  
Type I ◽  
Scattering Study ◽  
Hydrate Crystal

The inhibition of tetrahydrofuran clathrate-hydrate formation with antifreeze protein

2003 ◽  
Vol 81 (1-2) ◽  
pp. 17-24 ◽  
Author(s):  
H Zeng ◽  
L D Wilson ◽  
V K Walker ◽  
J A Ripmeester
Keyword(s):  
Induction Time ◽  
Crystal Morphology ◽  
Choristoneura Fumiferana ◽  
Hydrate Formation ◽  
Antifreeze Protein ◽  
Clathrate Hydrate ◽  
Inhibition Mechanism ◽  
Type I ◽  
Inhibition Activity ◽  
Hydrate Crystal

The effect of Type I fish antifreeze protein (AFP) from the winter flounder, Pleuronectes americanus (Walbaum), (WfAFP) on the formation of tetrahydrofuran (THF) clathrate hydrate was studied by observing changes in THF crystal morphology and determining the induction time for nucleation. AFP retarded THF clathrate-hydrate growth at the tested temperatures and modified the THF clathrate-hydrate crystal morphology from octahedral to plate-like. AFP appears to be even more effective than the kinetic inhibitor, polyvinylpyrrolidone (PVP). Recombinant AFP from an insect, a spruce budworm, Choristoneura fumiferana (Clem.), moth, (Cf) was also tested for inhibition activity by observation of the THF-hydrate-crystal-growth habit. Like WfAFP, CfAFP appeared to show adsorption on multiple THF-hydrate-crystal faces. A protein with no antifreeze activity, cytochrome C, was used as a control and it neither changed the morphology of the THF clathrate-hydrate crystals, nor retarded the formation of the hydrate. Preliminary experiments on the inhibition activity of WfAFP on a natural gas hydrate assessed induction time and the amount of propane gas consumed. Similar to the observations for THF, the data indicated that WfAFP inhibited propane-hydrate growth. Taken together, these results support our hypothesis that AFPs can inhibit clathrate-hydrate growth and as well, offer promise for the understanding of the inhibition mechanism. PACS No.: 87.90ty

Raman scattering study of type-I clathrate compounds: (, Sr, Ba)

2007 ◽  
Vol 310 (2) ◽  
pp. 954-956 ◽  
Author(s):  
Y. Takasu ◽  
T. Hasegawa ◽  
N. Ogita ◽  
M. Udagawa ◽  
M.A. Avila ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Type I ◽  
Clathrate Compounds ◽  
Scattering Study

scholarly journals Kinetic inhibition effect of Type I and III antifreeze proteins on unidirectional tetrahydrofuran hydrate crystal growth

RSC Advances ◽  
2019 ◽  
Vol 9 (20) ◽  
pp. 11530-11537 ◽  
Author(s):  
Michihiro Muraoka ◽  
Michika Ohtake ◽  
Yoshitaka Yamamoto
Keyword(s):  
Crystal Growth ◽  
Antifreeze Proteins ◽  
Clathrate Hydrate ◽  
Type I ◽  
Growth Technique ◽  
Inhibition Effect ◽  
Type Iii ◽  
Kinetic Inhibition ◽  
Hydrate Crystal

Experiments were performed to evaluate the kinetic inhibition effect of Type I and Type III antifreeze proteins (AFPs) on the growth of tetrahydrofuran (THF) clathrate hydrate crystals using the unidirectional growth technique.

Alkyl-chain disorder in tetraisohexylammonium bromide

2012 ◽  
Vol 68 (4) ◽  
pp. o152-o155 ◽  
Author(s):  
Malcolm A. Kelland ◽  
Amber L. Thompson
Keyword(s):  
Crystal Structure ◽  
Crystal Growth ◽  
Alkyl Chain ◽  
Growth Inhibitor ◽  
Ammonium Cation ◽  
Asymmetric Unit ◽  
Bromide Anion ◽  
Alkyl Chains ◽  
Hydrate Crystal ◽  
Structure Ii Clathrate Hydrate

Tetraisohexylammonium bromide [systematic name: tetrakis(4-methylpentyl)azanium bromide], C24H52N+·Br−, is a powerful structure II clathrate hydrate crystal-growth inhibitor. The crystal structure, in the space groupP3221, contains one ammonium cation and one bromide anion in the asymmetric unit, both on general positions. At 100 K, the ammonium cation exhibits one ordered isohexyl chain and three disordered isohexyl chains. At 250 K, all four isohexyl chains are disordered. In an effort to reduce the disorder in the alkyl chains, the crystal was thermally cycled, but the disorder remained, indicating that it is dynamic in nature.

Crystal structure of magnesium chromium vanadate Mg2CrV3O11, a member of the A2BV3O11 vanadate family

2007 ◽  
Vol 22 (3) ◽  
pp. 246-252 ◽  
Author(s):  
A. Worsztynowicz ◽  
S. M. Kaczmarek ◽  
W. Paszkowicz ◽  
R. Minikayev
Keyword(s):  
Crystal Structure ◽  
Rietveld Method ◽  
Ion Pairs ◽  
Exchange Constant ◽  
Type I ◽  
Type Ii ◽  
Paramagnetic Resonance ◽  
Interatomic Distances ◽  
Electron Paramagnetic ◽  
Full Occupancy

The crystal structure of recently discovered chromium (III) dimagnesium trivanadate (V) Mg2CrV3O11 was refined using the Rietveld method. The crystal system of Mg2CrV3O11 is triclinic with space group P1− (Mg1.7Zn0.3GaV3O11 type) and lattice parameters a=6.4057(1) Å, b=6.8111(1) Å, c=10.0640(2) Å, α=97.523(1)°, β=103.351(1)°, γ=101.750(1)°, and Z=2. The characteristic feature of compounds in the A2BV3O11 (A=Mg, Zn and B=Ga, Fe, Cr) family is a strong tendency to share the octahedral M(1) and M(2) sites by both divalent A and trivalent B atoms, and the bipyramidal M(3) sites occupied by divalent A ions. In the present refinement, the only constraint assuming full occupancy of the M(1), M(2), and M(3) sites leads to the following Cr/(Cr+Mg) ratios: 0.70(2) at M(1), 0.24(2) at M(2), and 0.03(2) at M(3). These occupancies are discussed and compared to those of isotypic compounds. The values of interatomic distances are found to be comparable with those reported by R. D. Shannon in 1976. Electron paramagnetic resonance has been also analyzed. Two absorption lines with g≈2.0 (type I) and g≈1.98 (type II) have been recorded in the EPR spectra, and attributed to V4+ ions and Cr3+–Cr3+ ion pairs, respectively. The exchange constant J between Cr3+ ions has been calculated.

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