scholarly journals Mechanochemical Knoevenagel condensation investigated in situ

2017 ◽  
Vol 13 ◽  
pp. 2010-2014 ◽  
Author(s):  
Sebastian Haferkamp ◽  
Franziska Fischer ◽  
Werner Kraus ◽  
Franziska Emmerling
Keyword(s):  
Knoevenagel Condensation ◽  
Direct Conversion ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
In Situ Data ◽  
Solvent Free Conditions ◽  
Yield Time

The mechanochemical Knoevenagel condensation of malononitrile with p-nitrobenzaldehyde was studied in situ using a tandem approach. X-ray diffraction and Raman spectroscopy were combined to yield time-resolved information on the milling process. Under solvent-free conditions, the reaction leads to a quantitative conversion to p-nitrobenzylidenemalononitrile within 50 minutes. The in situ data indicate that the process is fast and proceeds under a direct conversion. After stopping the milling process, the reaction continues until complete conversion. The continuous and the stopped milling process both result in crystalline products suitable for single crystal X-ray diffraction.

In situ time resolved wide angle X-ray diffraction study of nanotube carpet growth: Nature of catalyst particles and progressive nanotube alignment

Carbon ◽  
2015 ◽  
Vol 87 ◽  
pp. 246-256 ◽  
Author(s):  
Périne Landois ◽  
Mathieu Pinault ◽  
Stéphan Rouzière ◽  
Dominique Porterat ◽  
Cristian Mocuta ◽  
...  
Keyword(s):  
Diffraction Study ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray

Electric-field-induced lattice distortion in epitaxial BiFeO3 thin films as determined by in situ time-resolved x-ray diffraction

2017 ◽  
Vol 111 (8) ◽  
pp. 082907 ◽  
Author(s):  
Seiji Nakashima ◽  
Osami Sakata ◽  
Hiroshi Funakubo ◽  
Takao Shimizu ◽  
Daichi Ichinose ◽  
...  
Keyword(s):  
Thin Films ◽  
Electric Field ◽  
Lattice Distortion ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Bifeo3 Thin Films

Green rust as a precursor for magnetite: an in situ synchrotron based study

2008 ◽  
Vol 72 (1) ◽  
pp. 201-204 ◽  
Author(s):  
A. Sumoondur ◽  
S. Shaw ◽  
I. Ahmed ◽  
L. G. Benning
Keyword(s):  
Direct Evidence ◽  
Green Rust ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Subsequent Transformation ◽  
Rapid Formation ◽  
Reaction Proceeds

AbstractIn this study, direct evidence for the formation of magnetite via a green rust intermediate is reported. The Fe(II) induced transformation of ferrihydrite, was quantified in situ and under O2-free conditions using synchrotron-based time-resolved energy dispersive X-ray diffraction. At pH 9 and Fe(II)/Fe(III) ratios of 0.5 and 1, rapid growth (6 min) of sulphate green rust and its subsequent transformation to magnetite was observed. Electron microscopy confirmed these results, showing the initial rapid formation of hexagonal sulphate green rust particles, followed by the corrosion of the green rust as magnetite growth occurred, indicating that the reaction proceeds via a dissolution-reprecipitation mechanism. At pH 7 and Fe(II)/Fe(III) ratio of 0.5, sulphate green rust was the stable phase, with no transformation to magnetite.

Time-resolved, in situ X-ray diffraction studies of the hydrothermal syntheses of microporous materials

1998 ◽  
Vol 21 (4-6) ◽  
pp. 253-262 ◽  
Author(s):  
Dermot O'Hare ◽  
John S.O. Evans ◽  
Robin J. Francis ◽  
P. Shiv Halasyamani ◽  
Poul Norby ◽  
...  
Keyword(s):  
Microporous Materials ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Hydrothermal Syntheses

scholarly journals Elucidating the Structural Evolution of a Highy Porous Responsive Metal-Organic Framework (DUT-49(M)) upon Guests Desorption by Time-Resolved In-Situ Powder X-Ray Diffraction

2020 ◽  
Author(s):  
Bikash Garai ◽  
Volodymyr Bon ◽  
Francesco Walenszus ◽  
Azat Khadiev ◽  
Dmitri Novikov ◽  
...  
Keyword(s):  
Adsorption Isotherms ◽  
Metal Organic Framework ◽  
Structural Evolution ◽  
Structural Transformations ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Metal Organic ◽  
Subcritical Fluid

Variation in the metal centres of M-M paddle-wheel SBU results in the formation of isostructural DUT-49(M) frameworks. However, the porosity of the framework was found to be different for each of the structures. While a high and moderate porosity was obtained for DUT-49(Cu) and DUT-49(Ni), respectively, other members of the series [DUT-49(M); M= Mn, Fe, Co, Zn, Cd] show very low porosity and shapes of the adsorption isotherms which is not expected for op phases of these MOFs. Investigation on those MOFs revealed that those frameworks undergo structural collapse during the solvent removal at the activation step. Thus, herein, we aimed to study the detailed structural transformations that are possibly occurring during the removal of the subcritical fluid from the framework.

scholarly journals Time-resolved XRD experiments for a fine description of mechanisms induced during reactive sintering

2005 ◽  
Vol 37 (1) ◽  
pp. 27-34 ◽  
Author(s):  
S. Paris ◽  
E. Gaffet ◽  
D. Vrel ◽  
D. Thiaudiere ◽  
M. Gailhanou ◽  
...  
Keyword(s):  
Reactive Sintering ◽  
X Ray Diffraction ◽  
Reaction Parameters ◽  
Time Resolved ◽  
X Ray ◽  
Synthesis Conditions ◽  
Nanostructure Materials ◽  
Synchrotron Beam ◽  
The One

The control of Mechanically Activated Field Activated Pressure Assisted Synthesis hereafter called the MAFAPAS process is the main objective to be achieved for producing nanostructure materials with a controlled consolidation level. Consequently, it was essential to develop characterization tools "in situ" such as the Time Resolved X-ray Diffraction (TRXRD), with an X-ray synchrotron beam (H10, LURE Orsay) coupled to an infrared thermography to study simultaneously structural transformations and thermal evolutions. From the 2003 experiments, we took the opportunity to modify the sample-holder in order to reproduce the better synthesis conditions of the MAFAPAS process, but without the consolidation step. The versatility of the setup has been proved and could even be enhanced by the design of new sample holders. In addition, this work clearly shows that this equipment will allow, on the one hand, to make progress of the understanding of MAFAPAS mechanisms and, on the other hand, to adjust reaction parameters (mechanical activation and combustion synthesis) for producing many materials with an expected microstructure.

Cation Movements during Dehydration and NO2 Desorption in a Ba–Y,FAU Zeolite: An in Situ Time-Resolved X-ray Diffraction Study

2013 ◽  
Vol 117 (8) ◽  
pp. 3915-3922 ◽  
Author(s):  
Xianqin Wang ◽  
Jonathan C. Hanson ◽  
Ja Hun Kwak ◽  
Janos Szanyi ◽  
Charles H. F. Peden
Keyword(s):  
Diffraction Study ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Fau Zeolite

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
Sign in / Sign up

Export Citation Format

Share Document