Solid-state 27Al MRI and NMR thermometry for catalytic applications with conventional (liquids) MRI instrumentation and techniques

Koptyug, Igor V.; Sagdeev, Dmitry R.; Gerkema, E.; As, Henk Van; Sagdeev, R. Z.

doi:10.1016/j.jmr.2005.03.005

Cited by 27 publications

(20 citation statements)

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“…Specifically, flow maps and local density profiles can be generated, molecular mobility can be tracked, and chemical reaction mechanisms can be probed with spin-labeled nuclei [12]. Previous applications of MRI to heterogeneous catalysis included studies of hydrogenation processes without p−H 2 [92,133], catalyst morphologies and synthesis techniques [93,107], and fluid flow through the catalyst bed [106], as well as monitoring of esterification reactions [97,160] in situ. All of these applications were based on the NMR signal detection of the liquid phase and thus offer a sensitivity that is three orders of magnitude larger, as compared with gases, resulting from the difference in density.…”

Section: Methods To Characterize Micro-reactorsmentioning

confidence: 99%

“…2 and 4, many important chemical reactions take place in heterogeneous environments, such as fluids flowing through a packed-bed reactor where they react at the solid-fluid interface. The optimization of such packed bed reactors is an important problem in chemical engineering [92,93]. Characterizing heat and mass transport throughout the reactor is particularly important in the design and optimization of packedbed reactors.…”

Section: Introductionmentioning

confidence: 99%

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MRI of Heterogeneous Hydrogenation Reactions Using Parahydrogen Polarization

Burt

2008

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The power of magnetic resonance imaging (MRI) is its ability to image the internal structure of optically opaque samples and provide detailed maps of a variety of important parameters, such as density, diffusion, velocity and temperature. However, one of the fundamental limitations of this technique is its inherent low sensitivity. For example, the low signal to noise ratio (SNR) is particularly problematic for imaging gases in porous materials due to the low density of the gas and the large volume occluded by the porous material. This is unfortunate, as many industrially relevant chemical reactions take place at gas-surface interfaces in porous media, such as packed catalyst beds. Because of this severe SNR problem, many techniques have been developed to directly increase the signal strength. These techniques work by manipulating the nuclear spin populations to produce polarized (i.e. non-equilibrium) states with resulting signal strengths that are orders of magnitude larger than those available at thermal equilibrium. 2This dissertation is concerned with an extension of a polarization technique based on the properties of parahydrogen. Specifically, I report on the novel use of heterogeneous catalysis to produce parahydrogen induced polarization and applications of this new technique to gas phase MRI and the characterization of micro-reactors. First, I provide an overview of nuclear magnetic resonance (NMR) and how parahydrogen is used to improve the SNR of the NMR signal. I then present experimental results demonstrating that it is possible to use heterogeneous catalysis to produce parahydrogen-induced polarization.These results are extended to imaging void spaces using a parahydrogen polarized gas. In the second half of this dissertation, I demonstrate the use of parahydrogen-polarized gasphase MRI for characterizing catalytic microreactors. Specifically, I show how the improved SNR allows one to map parameters important for characterizing the heat and mass transport in a heterogeneous catalyst bed. This is followed by appendices containing detailed

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Section: Methods To Characterize Micro-reactorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

MRI of Heterogeneous Hydrogenation Reactions Using Parahydrogen Polarization

Burt

2008

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“…13 C NMR has been used to explore changes in selectivity and conversion in trickle bed reactors operating at up to 5 barg and 120 C (Akpa, Mantle, Sederman, & Gladden, 2005;Gladden et al, 2010;Sederman, Mantle, Dunckley, Huang, & Gladden, 2005). Koptyug et al have developed NMR thermometry techniques to permit the quantification of the temperature of catalyst pellets during reaction (Koptyug et al, 2008;Koptyug, Sagdeev, Gerkema, Van As, Sagdeev, 2005;Lysova, Kulikov, Parmon, Sagdeev, & Koptyug, 2012). For example, Figure 18.9 shows the temperature distribution in a Pt/g-Al 2 O 3 catalyst pellet when contacted on one side with a mixture of hydrogen and air.…”

Section: Reaction Studiesmentioning

confidence: 99%

Applications of tomography in bubble column and trickle bed reactors

Holland

2015

Industrial Tomography

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“…In this context, the use of active and reusable heterogeneous catalyzed processes will enable the production of catalyst-free polarized fluids (after separation of the catalyst from the reaction products) and also polarized gases. MRI has also been employed to study catalyst morphologies and synthesis techniques [103,104].…”

Section: Advanced Nmr Applicationsmentioning

confidence: 99%

Designer Nanomaterials for the Production of Energy and High Value‐Added Chemicals

Luque

2010

Ideas in Chemistry and Molecular Sciences

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Solid-state 27Al MRI and NMR thermometry for catalytic applications with conventional (liquids) MRI instrumentation and techniques

Cited by 27 publications

References 50 publications

MRI of Heterogeneous Hydrogenation Reactions Using Parahydrogen Polarization

MRI of Heterogeneous Hydrogenation Reactions Using Parahydrogen Polarization

Applications of tomography in bubble column and trickle bed reactors

Designer Nanomaterials for the Production of Energy and High Value‐Added Chemicals

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