Nuclear Magnetic Resonance and Broadband Dielectric Spectroscopy Studies on the Dynamics of Ethylene Glycol in Mesoporous Silica

2020 ◽  
Vol 124 (38) ◽  
pp. 20998-21012 ◽  
Author(s):  
Melanie Reuhl ◽  
Max Weigler ◽  
Martin Brodrecht ◽  
Gerd Buntkowsky ◽  
Michael Vogel
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Mesoporous Silica ◽  
Ethylene Glycol ◽  
Dielectric Spectroscopy ◽  
Broadband Dielectric Spectroscopy ◽  
Spectroscopy Studies ◽  
Nuclear Magnetic

Slow Motion of Confined Molecules: NMR and Broadband Dielectric Spectroscopy Investigations

2008 ◽  
Vol 8 (2) ◽  
pp. 887-893 ◽  
Author(s):  
Özlen F. Erdem ◽  
André Pampel ◽  
Dieter Michel
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Ethylene Glycol ◽  
Spin Relaxation ◽  
Dielectric Spectroscopy ◽  
Proton Spin ◽  
Magic Angle ◽  
Glass Forming ◽  
Broadband Dielectric Spectroscopy ◽  
Nuclear Magnetic

Nuclear magnetic resonance (NMR) and broadband dielectric spectroscopy are used to investigate the dynamics of small glass-forming molecules confined to restricted geometries. Ethylene glycol molecules are embedded in the supercages of NaX zeolites. The combined application of NMR and broadband dielectric spectroscopy advances the understanding of the slowing down of the motion near the glass transition temperature of these confined molecules. In combination with nuclear spin relaxation and nuclear magnetic resonance spectroscopy, dielectric relaxation studies on glass forming molecules allow conclusions on the character of the motion. High resolution 1H magic angle spinning (MAS) NMR measurements not only enable a characterisation of the state of the adsorbed molecules via a chemical shift analysis. By means of an analysis of MAS spinning sidebands we may also estimate a correlation time the meaning of which will be discussed in comparison to the results of longitudinal proton spin relaxation measurements. In addition to broadband dielectric spectroscopy slow molecular motions of partially deuterated ethylene glycol adsorbed in NaX are studied by means of 2H NMR line-shape analysis.

Solid-state 27Al Nuclear Magnetic Resonance Investigation of Plasma-facilitated NOx Reduction Catalysts

2002 ◽  
Vol 17 (7) ◽  
pp. 1843-1848 ◽  
Author(s):  
Li-Qiong Wang ◽  
Christopher L. Aardahl ◽  
Kenneth G. Rappé ◽  
Diana N. Tran ◽  
Marisol A. Delgado ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Solid State ◽  
Magnetic Resonance ◽  
Mesoporous Silica ◽  
Catalytic Reduction ◽  
Nox Reduction ◽  
Sodium Aluminate ◽  
Acid Sites ◽  
Structural Defects ◽  
Nuclear Magnetic

Aluminum coordination distribution for alumina catalysts supported on mesoporous silica was examined. It was shown that aluminum coordination correlates to activity of the catalysts for plasma-enhanced, selective catalytic reduction of NOx with propene. Catalysts were prepared by incorporating aluminum onto the surface of a mesoporous silica support via three different post-synthesis routes to produce varying aluminum coordination. Aluminum trichloride, sodium aluminate, and aluminum isopropoxide precursors were examined. High-resolution, solid state 27Al nuclear magnetic resonance was used to determine aluminum coordination distributions for the resulting catalysts. Unsaturated aluminum sites (i.e., structural defects) correlated with increased activity at high temperatures while tetrahedrally-coordinated aluminum or BrØnsted acid sites correlated with activity at low temperatures.

Proton Nuclear Magnetic Resonance Spectroscopic Detection and Determination of Ethylene Glycol Dimethacrylate as a Contaminant of Methyl Methacrylate Raw Material

1995 ◽  
Vol 78 (4) ◽  
pp. 954-958
Author(s):  
George M Hanna ◽  
Cesar A Lau-Cam
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Ethylene Glycol ◽  
Methyl Methacrylate ◽  
Spectroscopic Method ◽  
Ethylene Glycol Dimethacrylate ◽  
Raw Material ◽  
Proton Nuclear Magnetic Resonance ◽  
Glycol Dimethacrylate ◽  
Nuclear Magnetic

Abstract A simple, specific, and accurate proton nuclear magnetic resonance (1H NMR) spectroscopic method is presented for detection and assay of ethylene glycol dimethacrylate dimer as a contaminant of methyl methacrylate monomer. In addition to minimizing exposure of the analyst to the irritant and toxic methacrylic acid esters, the proposed method requires no sample preparation. Quantitations are based on integrals for signals of methylene protons of ethylene glycol dimethacrylate at 4.37 ppm and methyl protons of methyl methacrylate at 3.70 ppm. Analysis of 10 synthetic mixtures of the monomer with 1–11% of dimer yielded a dimer recovery of 100.5 ± 2.05% (mean ± standard deviation). Correspondence (correlation coefficient, r=0.9999) between the amount of dimer added and the amount found was excellent. The proposed method measures as little as 1% of dimer.

scholarly journals NMR and Impedance Spectroscopy Studies on Lithium Ion Diffusion in Microcrystalline γ-LiAlO2

2015 ◽  
Vol 229 (9) ◽  
Author(s):  
Elena Witt ◽  
Suliman Nakhal ◽  
C. Vinod Chandran ◽  
Martin Lerch ◽  
Paul Heitjans
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Impedance Spectroscopy ◽  
Lithium Ion ◽  
Ion Dynamics ◽  
Ion Diffusion ◽  
Li Ion ◽  
Spectroscopy Studies ◽  
Lithium Ion Diffusion ◽  
Nuclear Magnetic

AbstractIn this work nuclear magnetic resonance (NMR) and impedance spectroscopy (IS) studies on Li ion dynamics in microcrystalline

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