Selective Single‐Site Pd−In Hydrogenation Catalyst for Production of Enhanced Magnetic Resonance Signals using Parahydrogen

Burueva, Dudari B.; Kovtunov, Kirill V.; Bukhtiyarov, Andrey V.; Barskiy, Danila A.; Prosvirin, Igor P.; Mashkovsky, Igor S.; Баева, Г. Н.; Bukhtiyarov, Valerii I.; Stakheev, A. Yu.; Koptyug, Igor V.

doi:10.1002/chem.201705644

Cited by 61 publications

(64 citation statements)

References 68 publications

(77 reference statements)

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“…One such suitable catalyst is the PdÀIn/Al 2 O 3 single-site catalyst. [174] This catalyst demonstrated high selectivity for propene (up to 98 %), as well as significant signal enhancement (ca. 3400-fold for the CH group of propene, which corresponded to 9.4 %p olarization),w hilst the conversion of propyne reached1 8%.T his reactiona llowed the acquisition of a 1 HMRI of hyperpolarizedp ropene (Figure 9), whichc ould be used for the developmento fM RI techniques for the in situ visualization of selectivecatalytic hydrogenation reactions.…”

Section: Heterogeneous Mrimentioning

confidence: 99%

“…One interesting approach is the production of hyperpolarized propene from propyne, which would require the use of a selective catalyst. One such suitable catalyst is the Pd−In/Al 2 O 3 single‐site catalyst . This catalyst demonstrated high selectivity for propene (up to 98 %), as well as significant signal enhancement (ca.…”

Section: Heterogeneous Mrimentioning

confidence: 99%

“…The matrix size and spatial resolution were 64 64 and 0.8 0.8 mm 2 pixel À1 ,r espectively.Reproduced from Ref. [174].…”

Section: âãmentioning

confidence: 99%

See 2 more Smart Citations

Hyperpolarized NMR Spectroscopy: d‐DNP, PHIP, and SABRE Techniques

Kovtunov

Pokochueva

Salnikov

et al. 2018

Chemistry An Asian Journal

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232

237

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The intensity of NMR signals can be enhanced by several orders of magnitude by using various techniques for the hyperpolarization of different molecules. Such approaches can overcome the main sensitivity challenges facing modern NMR/magnetic resonance imaging (MRI) techniques, whilst hyperpolarized fluids can also be used in a variety of applications in material science and biomedicine. This Focus Review considers the fundamentals of the preparation of hyperpolarized liquids and gases by using dissolution dynamic nuclear polarization (d-DNP) and parahydrogen-based techniques, such as signal amplification by reversible exchange (SABRE) and parahydrogen-induced polarization (PHIP), in both heterogeneous and homogeneous processes. The various new aspects in the formation and utilization of hyperpolarized fluids, along with the possibility of observing NMR signal enhancement, are described.

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Section: Heterogeneous Mrimentioning

confidence: 99%

Section: Heterogeneous Mrimentioning

confidence: 99%

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Hyperpolarized NMR Spectroscopy: d‐DNP, PHIP, and SABRE Techniques

Kovtunov

Pokochueva

Salnikov

et al. 2018

Chemistry An Asian Journal

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232

237

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“…Moreover, a 3000‐fold increase in the pairwise selectivity based on the signal enchancement, relative to that of monometallic Pt, was observed by using PtSn@mSiO 2 . The approach of using intermetallic catalysts to maximize HET‐PHIP effects was later developed by the group of Koptyug . A 3400‐fold NMR signal enhancement, corresponding to 9.3 % pairwise H 2 addition (estimated by taking account of relaxation processes), was observed in propyne hydrogenation over the Pd−In/Al 2 O 3 single‐site catalyst.…”

Section: Single‐site Catalysts In the Context Of Nmr Sensitivity Imprmentioning

confidence: 99%

Single‐Site Heterogeneous Catalysts: From Synthesis to NMR Signal Enhancement

Burueva

Kovtunova

Bukhtiyarov

et al. 2018

Chemistry A European J

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Catalysts with well-defined, single, active centers are of great importance and their utilization allows the gap between homo- and heterogeneous catalysis to be bridged and, importantly, the main selectivity problem of heterogeneous catalysis and the main separation challenge of homogeneous catalysis to be overcome. Moreover, the use of single-site catalysts allows the NMR signal to be significantly enhanced through the pairwise addition of two hydrogen atoms from a parahydrogen molecule to an unsaturated substrate. This review covers the fundamentals of the synthesis of single-site catalysts and shows the new aspects of their applications in both modern catalysis and the field of parahydrogen-based hyperpolarization. The different novel aspects of the formation and utilization of single-site catalysts, along with the possibility of NMR signal enhancement observations are described.

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“…[32] Taking into account mentioned constrains of the polarizable gases in SEOP and DNP methods, heterogeneous PHIP [33,34] (HET-PHIP) has emerged as an attractive alternative because of its simplicity and robustness for the production of hyperpolarized (HP) gases. [47][48][49] Several imaging reports of HP products relied on the PHIP methodology with conventional MRI scanners, [50][51][52][53] however, only two studies have used PHIP for imaging of the formed hyperpolarized gas within a catalyst bed directly [54] and by applying remote detection NMR technique. [35] The PHIP phenomenon was observed in homogeneous [36] and heterogeneous catalysis.…”

mentioning

confidence: 99%

Robust In Situ Magnetic Resonance Imaging of Heterogeneous Catalytic Hydrogenation with and without Hyperpolarization

Kovtunov

Lebedev²,

Svyatova

et al. 2019

ChemCatChem

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Magnetic resonance imaging (MRI) is a powerful technique to characterize reactors during operating catalytic processes. However, MRI studies of heterogeneous catalytic reactions are particularly challenging because the low spin density of reacting and product fluids (for gas phase reactions) as well as magnetic field inhomogeneity, caused by the presence of a solid catalyst inside a reactor, exacerbate already low intrinsic sensitivity of this method. While hyperpolarization techniques such as parahydrogen induced polarization (PHIP) can substantially increase the NMR signal intensity, this general strategy to enable MR imaging of working heterogeneous catalysts to date remains underexplored. Here, we present a new type of model catalytic reactors for MRI that allow the characterization of a heterogeneous hydrogenation reaction aided by the PHIP signal enhancement, but also suitable for the imaging of regular nonpolarized gases. These catalytic systems permit exploring the complex interplay between chemistry and fluid-dynamics that are typically encountered in practical systems, but mostly absent in simple batch reactors. High stability of the model reactors at catalytic conditions and their fabrication simplicity make this approach compelling for in situ studies of heterogeneous catalytic processes by MRI.Catalytic processes (e. g., hydrogenation, reforming, oxidation, etc.) are at the cornerstone of chemical and petrochemical industry [1] and, to make these processes more sustainable, control over reaction selectivity, conversion rates, mass and heat transport inside the working reactor (that is under operando conditions) is required. Magnetic resonance imaging (MRI) is a tool applicable to operando studies that provide information for example about the distribution of liquids in the catalyst pellet during hydrogenation of α-methylstyrene [2] or heptene, [3] the coke profiles within a catalyst pellet, [4] the flow of water [5] or propane [6] through a packed bed, the structure of a porous medium and the water flow during the deposition of fines, [7] or the velocities of particles in a fluidized bed. [8][9][10] MRI of reactors utilizing gases are not as developed as studies of liquids because the spin density in the gas phase is ca. 3 orders of magnitude lower relative to the condensed phase, which significantly limits the deployment of MRI for studying gases. [11] Nevertheless, a recent report showed that the distribution of the reactants and products inside a monolith type reactor can be measured even in the gas phase during ethylene hydrogenation reaction using two different catalyst supports, thereby revealing an effect of the support on the mass and heat transport. [12] Overall, to date, there are only a handful of MRI studies of the gas phase reactions with regular non-hyperpolarized gases. [13,14] The limitation of low NMR sensitivity spurs the implementation of hyperpolarization techniques, which can potentially increase the intensity of NMR signals by up to several orders of magnitude, including spin-ex...

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Selective Single‐Site Pd−In Hydrogenation Catalyst for Production of Enhanced Magnetic Resonance Signals using Parahydrogen

Cited by 61 publications

References 68 publications

Hyperpolarized NMR Spectroscopy: d‐DNP, PHIP, and SABRE Techniques

Hyperpolarized NMR Spectroscopy: d‐DNP, PHIP, and SABRE Techniques

Single‐Site Heterogeneous Catalysts: From Synthesis to NMR Signal Enhancement

Robust In Situ Magnetic Resonance Imaging of Heterogeneous Catalytic Hydrogenation with and without Hyperpolarization

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