Kinetics of phase transformations in crystals of drug compounds using time-resolved powder x-ray diffraction

1992 ◽  
Vol 39 (1-4) ◽  
pp. 3-11 ◽  
Author(s):  
J. Anwar ◽  
P. Barnes
Keyword(s):  
Phase Transformations ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Drug Compounds ◽  
Kinetics Of

Kinetics of Multi-Step Redox Processes by Time-Resolved In Situ X-ray Diffraction

2016 ◽  
Vol 88 (11) ◽  
pp. 1684-1692 ◽  
Author(s):  
Lukas C. Buelens ◽  
Vladimir V. Galvita ◽  
Hilde Poelman ◽  
Christophe Detavernier ◽  
Guy B. Marin
Keyword(s):  
Redox Processes ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Kinetics Of

Kinetics of the lamellar-inverse hexagonal phase transition determined by time-resolved x-ray diffraction

Biochemistry ◽  
1992 ◽  
Vol 31 (4) ◽  
pp. 1081-1092 ◽  
Author(s):  
Mark W. Tate ◽  
Erramilli Shyamsunder ◽  
Sol M. Gruner ◽  
Kevin L. D'Amico
Keyword(s):  
Phase Transition ◽  
Hexagonal Phase ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Kinetics Of

Kinetics of high-pressure mineral phase transformations using in situ time-resolved X-ray diffraction in the Paris-Edinburgh cell: a practical guide for data acquisition and treatment

2008 ◽  
Vol 72 (2) ◽  
pp. 683-695 ◽  
Author(s):  
J. P. Perrillat
Keyword(s):  
High Pressure ◽  
Phase Transformations ◽  
Kinetic Studies ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Practical Guide ◽  
Set Up ◽  
Isothermal Kinetic

AbstractSynchrotron X-ray diffraction (XRD) is a powerful technique to study in situ and in real-time the structural and kinetic processes of pressure-induced phase transformations. This paper presents the experimental set-up developed at beamline ID27 of the ESRF to perform time-resolved angle dispersive XRD in the Paris-Edinburgh cell. It provides a practical guide for the acquisition of isobaric-isothermal kinetic data and the construction of transformation-time plots. The interpretation of experimental data in terms of reaction mechanisms and transformation rates is supported by an overview of the kinetic theory of solid-solid transformations, with each step of data processing illustrated by experimental results of relevance to the geosciences. Reaction kinetics may be affected by several factors such as the sample microstructure, impurities or differential stress. Further high-pressure kinetic studies should investigate the influence of such processes, in order to acquire kinetic information more akin to natural or technological processes.

scholarly journals Spatiotemporal reaction kinetics of an ultrafast photoreaction pathway visualized by time-resolved liquid x-ray diffraction

2006 ◽  
Vol 103 (25) ◽  
pp. 9410-9415 ◽  
Author(s):  
T. K. Kim ◽  
M. Lorenc ◽  
J. H. Lee ◽  
M. Lo Russo ◽  
J. Kim ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Kinetics Of

Influence of oxygen partial pressure on the kinetics of YBa2Cu3O7−x formation

1994 ◽  
Vol 9 (2) ◽  
pp. 275-285 ◽  
Author(s):  
V. Milonopoulou ◽  
K.M. Forster ◽  
J.P. Formica ◽  
J. Kulik ◽  
J.T. Richardson ◽  
...  
Keyword(s):  
X Ray Diffraction ◽  
Decomposition Products ◽  
Time Resolved ◽  
X Ray ◽  
Formation Kinetics ◽  
Dimensional Diffusion ◽  
Diffusion Controlled ◽  
Gas Atmosphere ◽  
Kinetics Of

The YBa2Cu3O7−x formation kinetics from a spray-roasted precursor powder containing Y2O3, BaCO3, and CuO was followed via in situ, time-resolved x-ray diffraction as a function of gas atmosphere and temperature. In inert atmospheres, BaCO3 and CuO form BaCu2O2 which subsequently reacts with Y2O3 to form YBa2Cu3O6. However, YBa2Cu3O6 decomposes at temperatures exceeding 725 °C with Y2BaCuO5 being one of the decomposition products. In oxidizing atmospheres, YBa2Cu3O7−x formation involves the BaCuO2. At high temperatures (800–840 °C), oxygen increases the yield of YBa2Cu3O6. A nuclei growth model assuming two-dimensional, diffusion-controlled growth with second-order nucleation rate fits the experimental data.

Properties of Pure and Sulfided NiMoO4 and CoMoO4 Catalysts: Tpr, Xanes and Time-Resolved XRD Studdzs

1997 ◽  
Vol 497 ◽  
Author(s):  
S. Chaturvedi ◽  
J. A. Rodriguez ◽  
J. C. Hanson ◽  
A. Albornoz ◽  
J. L. Brito
Keyword(s):  
Electronic Properties ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
Direct Transformation ◽  
X Ray ◽  
Β Phase ◽  
Structural And Electronic Properties ◽  
X Ray Absorption ◽  
Kinetics Of ◽  
Cobalt And Nickel

ABSTRACTX-ray absorption near-edge spectroscopy (XANES) was used to characterize the structural and electronic properties of a series of cobalt- and nickel-molybdate catalysts (AMoO4.nH20, α-AMoO4, β-AMoO4; A= Co or Ni). The results of XANES indicate that the Co and Ni atoms are in octahedral sites in all these compounds, while the coordination of Mo varies from octahedral in the a-phases to tetrahedral in the β-phases and hydrate. Time-resolved x-ray diffraction shows a direct transformation of the hydrates into the β-AMoO4 compounds (following a kinetics of first order) at temperatures between 200 and 350 °C. This is facilitated by the similarities that the AMoO4.nH20 and β-AMoO4 compounds have in their structural and electronic properties. The molybdates react with H 2 at temperatures between 400 and 600 °C, forming gaseous water and oxides in which the oxidation state of Co and Ni remains +2 while that of Mo is reduced to +5 or +4. After exposing α-NiMoO4 and P-NiMoO4 to H2S, both metals get sulfided and a NiMoSx phase is formed. For the β phase of NiMoO4 the sulfidation of Mo is more extensive than for the a phase, making the former a better precursor for catalysts of hydrodesulfurization reactions.

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