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Title: Operando MAS NMR Reaction Studies at High Temperatures and Pressures

Abstract

Operando MAS-NMR studies provide unique insights into the details of chemical reactions; comprehensive information about temperature- and time-dependent changes in chemical species is accompanied by similarly rich information about changes in phase and chemical environment. Here we describe a new MAS-NMR rotor (the WHiMS rotor) capable of achieving internal pressures up to 400 bar at 20 °C or 225 bar at 250 °C, a range which includes many reactions of interest. The MAS-NMR spectroscopy enabled by these rotors is ideal for studying the behavior of mixed-phase systems, such as reactions involving solid catalysts and volatile liquids, with the potential to add gases at high pressure. The versatile operation of the new rotors is demonstrated by collecting operando 1H and 13C spectra during the hydrogenolysis of benzyl phenyl ether, catalyzed by Ni/-Al2O3 at ca. 250 ºC, both with and without H2 (g) supplied to the rotor. The 2-propanol solvent, which exists in the supercritical phase under these reaction conditions, serves as an internal source of H2. The NMR spectra provide detailed kinetic profiles for the formation of the primary products toluene and phenol, as well as secondary hydrogenation and etherification products.

Authors:
ORCiD logo [1]; ORCiD logo; ORCiD logo;  [1];  [1]; ORCiD logo; ORCiD logo [1]
  1. Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, United States
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1439024
Report Number(s):
PNNL-SA-130852
Journal ID: ISSN 1932-7447; 48157; 49121; KP1704020
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry. C; Journal Volume: 122; Journal Issue: 15
Country of Publication:
United States
Language:
English
Subject:
Environmental Molecular Sciences Laboratory

Citation Formats

Walter, Eric D., Qi, Long, Chamas, Ali, Mehta, Hardeep S., Sears, Jesse A., Scott, Susannah L., and Hoyt, David W. Operando MAS NMR Reaction Studies at High Temperatures and Pressures. United States: N. p., 2018. Web. doi:10.1021/acs.jpcc.7b11442.
Walter, Eric D., Qi, Long, Chamas, Ali, Mehta, Hardeep S., Sears, Jesse A., Scott, Susannah L., & Hoyt, David W. Operando MAS NMR Reaction Studies at High Temperatures and Pressures. United States. doi:10.1021/acs.jpcc.7b11442.
Walter, Eric D., Qi, Long, Chamas, Ali, Mehta, Hardeep S., Sears, Jesse A., Scott, Susannah L., and Hoyt, David W. Mon . "Operando MAS NMR Reaction Studies at High Temperatures and Pressures". United States. doi:10.1021/acs.jpcc.7b11442.
@article{osti_1439024,
title = {Operando MAS NMR Reaction Studies at High Temperatures and Pressures},
author = {Walter, Eric D. and Qi, Long and Chamas, Ali and Mehta, Hardeep S. and Sears, Jesse A. and Scott, Susannah L. and Hoyt, David W.},
abstractNote = {Operando MAS-NMR studies provide unique insights into the details of chemical reactions; comprehensive information about temperature- and time-dependent changes in chemical species is accompanied by similarly rich information about changes in phase and chemical environment. Here we describe a new MAS-NMR rotor (the WHiMS rotor) capable of achieving internal pressures up to 400 bar at 20 °C or 225 bar at 250 °C, a range which includes many reactions of interest. The MAS-NMR spectroscopy enabled by these rotors is ideal for studying the behavior of mixed-phase systems, such as reactions involving solid catalysts and volatile liquids, with the potential to add gases at high pressure. The versatile operation of the new rotors is demonstrated by collecting operando 1H and 13C spectra during the hydrogenolysis of benzyl phenyl ether, catalyzed by Ni/-Al2O3 at ca. 250 ºC, both with and without H2 (g) supplied to the rotor. The 2-propanol solvent, which exists in the supercritical phase under these reaction conditions, serves as an internal source of H2. The NMR spectra provide detailed kinetic profiles for the formation of the primary products toluene and phenol, as well as secondary hydrogenation and etherification products.},
doi = {10.1021/acs.jpcc.7b11442},
journal = {Journal of Physical Chemistry. C},
number = 15,
volume = 122,
place = {United States},
year = {Mon Jan 29 00:00:00 EST 2018},
month = {Mon Jan 29 00:00:00 EST 2018}
}