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Title: A Large Sample Volume Magic Angle Spinning Nuclear Magnetic Resonance Probe for In-Situ Investigations with Constant Flow of Reactants

Abstract

A large-sample-volume constant-flow magic angle sample spinning (CF-MAS) NMR probe is reported for in-situ studies of the reaction dynamics, stable intermediates/transition states, and mechanisms of catalytic reactions. In our approach, the reactants are introduced into the catalyst bed using a fixed tube at one end of the MAS rotor while a second fixed tube, linked to a vacuum pump, is attached at the other end of the rotor. The pressure difference between both ends of the catalyst bed inside the sample cell space forces the reactants flowing through the catalyst bed, which improves the diffusion of the reactants and products. This design allows the use of a large sample volume for enhanced sensitivity and thus permitting in-situ 13C CF-MAS studies at natural abundance. As an example of application, we show that reactants, products and reaction transition states associated with the 2-butanol dehydration reaction over a mesoporous silicalite supported heteropoly acid catalyst (HPA/meso-silicalite-1) can all be detected in a single 13C CF-MAS NMR spectrum at natural abundance. Coke products can also be detected at natural 13C abundance and under the stopped flow condition. Furthermore, 1H CF-MAS NMR is used to identify the surface functional groups of HPA/meso-silicalite-1 under the condition ofmore » in-situ drying . We also show that the reaction dynamics of 2-butanol dehydration using HPA/meso-silicalite-1 as a catalyst can be explored using 1H CF-MAS NMR.« less

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1034228
Report Number(s):
PNNL-SA-82533
Journal ID: ISSN 1463-9076; 32911; 35599; KC0302010; TRN: US201203%%451
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Physical Chemistry Chemical Physics
Additional Journal Information:
Journal Volume: 14; Journal Issue: 7; Journal ID: ISSN 1463-9076
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; ABUNDANCE; CATALYSTS; COKE; DEHYDRATION; DESIGN; DIFFUSION; DRYING; FUNCTIONALS; INORGANIC ACIDS; NUCLEAR MAGNETIC RESONANCE; PROBES; ROTORS; SENSITIVITY; VACUUM PUMPS; In-situ NMR; constant flow; sensitivity enhancement; natural abundance 13C NMR; catalyst reaction; 2-butanol dehydration; heteropoly acid; Environmental Molecular Sciences Laboratory

Citation Formats

Hu, Jian Z, Sears, Jesse A, Mehta, Hardeep S, Ford, Joseph J, Kwak, Ja Hun, Zhu, Kake, Wang, Yong, Liu, Jun, Hoyt, David W, and Peden, Charles HF. A Large Sample Volume Magic Angle Spinning Nuclear Magnetic Resonance Probe for In-Situ Investigations with Constant Flow of Reactants. United States: N. p., 2012. Web. doi:10.1039/c1cp22692d.
Hu, Jian Z, Sears, Jesse A, Mehta, Hardeep S, Ford, Joseph J, Kwak, Ja Hun, Zhu, Kake, Wang, Yong, Liu, Jun, Hoyt, David W, & Peden, Charles HF. A Large Sample Volume Magic Angle Spinning Nuclear Magnetic Resonance Probe for In-Situ Investigations with Constant Flow of Reactants. United States. doi:10.1039/c1cp22692d.
Hu, Jian Z, Sears, Jesse A, Mehta, Hardeep S, Ford, Joseph J, Kwak, Ja Hun, Zhu, Kake, Wang, Yong, Liu, Jun, Hoyt, David W, and Peden, Charles HF. Tue . "A Large Sample Volume Magic Angle Spinning Nuclear Magnetic Resonance Probe for In-Situ Investigations with Constant Flow of Reactants". United States. doi:10.1039/c1cp22692d.
@article{osti_1034228,
title = {A Large Sample Volume Magic Angle Spinning Nuclear Magnetic Resonance Probe for In-Situ Investigations with Constant Flow of Reactants},
author = {Hu, Jian Z and Sears, Jesse A and Mehta, Hardeep S and Ford, Joseph J and Kwak, Ja Hun and Zhu, Kake and Wang, Yong and Liu, Jun and Hoyt, David W and Peden, Charles HF},
abstractNote = {A large-sample-volume constant-flow magic angle sample spinning (CF-MAS) NMR probe is reported for in-situ studies of the reaction dynamics, stable intermediates/transition states, and mechanisms of catalytic reactions. In our approach, the reactants are introduced into the catalyst bed using a fixed tube at one end of the MAS rotor while a second fixed tube, linked to a vacuum pump, is attached at the other end of the rotor. The pressure difference between both ends of the catalyst bed inside the sample cell space forces the reactants flowing through the catalyst bed, which improves the diffusion of the reactants and products. This design allows the use of a large sample volume for enhanced sensitivity and thus permitting in-situ 13C CF-MAS studies at natural abundance. As an example of application, we show that reactants, products and reaction transition states associated with the 2-butanol dehydration reaction over a mesoporous silicalite supported heteropoly acid catalyst (HPA/meso-silicalite-1) can all be detected in a single 13C CF-MAS NMR spectrum at natural abundance. Coke products can also be detected at natural 13C abundance and under the stopped flow condition. Furthermore, 1H CF-MAS NMR is used to identify the surface functional groups of HPA/meso-silicalite-1 under the condition of in-situ drying . We also show that the reaction dynamics of 2-butanol dehydration using HPA/meso-silicalite-1 as a catalyst can be explored using 1H CF-MAS NMR.},
doi = {10.1039/c1cp22692d},
journal = {Physical Chemistry Chemical Physics},
issn = {1463-9076},
number = 7,
volume = 14,
place = {United States},
year = {2012},
month = {2}
}