The effect of oxidative and reductive treatments of titania-supported metal catalysts on the pairwise hydrogen addition to unsaturated hydrocarbons

Salnikov, Oleg G.; Burueva, Dudari B.; Gerasimov, E. Yu.; Bukhtiyarov, Andrey V.; Khudorozhkov, Alexander K.; Prosvirin, Igor P.; Kovtunova, Larisa M.; Barskiy, Danila A.; Bukhtiyarov, Valerii I.; Kovtunov, Kirill V.; Koptyug, Igor V.

doi:10.1016/j.cattod.2016.02.030

Cited by 20 publications

(22 citation statements)

References 34 publications

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“…Second, the performance of Rh/TiO 2 catalysts in hydrogenation of propargyl esters with p‐H 2 was inferior to that in case of hydrogenation of esters with a C=C bond. This is in agreement with results of gas‐phase hydrogenation of propyne and propylene with p‐H 2 over Rh/TiO 2 catalyst [82] . In that study the intensities of 1 H NMR signals of HP propane were higher than those of HP propylene under otherwise similar reaction conditions.…”

Section: Resultssupporting

confidence: 90%

Heterogeneous ¹H and ¹³C Parahydrogen‐Induced Polarization of Acetate and Pyruvate Esters

et al. 2021

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Magnetic resonance imaging of [1‐13C]hyperpolarized carboxylates (most notably, [1‐13C]pyruvate) allows one to visualize abnormal metabolism in tumors and other pathologies. Herein, we investigate the efficiency of 1H and 13C hyperpolarization of acetate and pyruvate esters with ethyl, propyl and allyl alcoholic moieties using heterogeneous hydrogenation of corresponding vinyl, allyl and propargyl precursors in isotopically unlabeled and 1‐13C‐enriched forms with parahydrogen over Rh/TiO2 catalysts in methanol‐d4 and in D2O. The maximum obtained 1H polarization was 0.6±0.2 % (for propyl acetate in CD3OD), while the highest 13C polarization was 0.10±0.03 % (for ethyl acetate in CD3OD). Hyperpolarization of acetate esters surpassed that of pyruvates, while esters with a triple carbon‐carbon bond in unsaturated alcoholic moiety were less efficient as parahydrogen‐induced polarization precursors than esters with a double bond. Among the compounds studied, the maximum 1H and 13C NMR signal intensities were observed for propyl acetate. Ethyl acetate yielded slightly less intense NMR signals which were dramatically greater than those of other esters under study.

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Section: Resultssupporting

confidence: 90%

Heterogeneous ¹H and ¹³C Parahydrogen‐Induced Polarization of Acetate and Pyruvate Esters

et al. 2021

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“…The scope of heterogeneous catalysts which are suitable for PHIP increased significantly in the past 10 years. For instance, PHIP was successfully observed over various metal catalysts such as Rh, Pt, Pd, Ir, Au, Cu, bimetallic systems Pt−Sn, Pd−Au, Pd−M (M=Sn, Zn, Ag, Mn, Pb, Au) supported on support materials such as SiO 2 , ZrO 2 , Al 2 O 3 , TiO 2 , Al−Si fiberglass, chitosan, carbon nanotubes . Moreover, the PHIP effect was demonstrated for bulk Pt metal and several metal oxides (PtO 2 , PdO and CeO 2 ).…”

Section: Hydrogenation Of Propyne With Parahydrogen Over Pd−in/al2o3 mentioning

confidence: 96%

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

Burueva

Kovtunov

Bukhtiyarov

et al. 2018

Chemistry A European J

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Pd-In/Al O single-site catalyst was able to show high selectivity (up to 98 %) in the gas phase semihydrogenation of propyne. Formation of intermetallic Pd-In compound was studied by XPS during reduction of the catalyst. FTIR-CO spectroscopy confirmed single-site nature of the intermetallic Pd-In phase reduced at high temperature. Utilization of Pd-In/Al O in semihydrogenation of propyne with parahydrogen allowed to produce ≈3400-fold NMR signal enhancement for reaction product propene (polarization=9.3 %), demonstrating the large contribution of pairwise hydrogen addition route. Significant signal enhancement as well as the high catalytic activity of the Pd-In catalyst allowed to acquire H MR images of flowing hyperpolarized propene gas selectively for protons in CH, CH and CH groups. This observation is unique and can be easily transferred to the development of a useful MRI technique for an in situ investigation of selective semihydrogenation in catalytic reactors.

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“…The resulting significant 1 H NMR signal enhancement facilitated the imaging of various model objects, and was later used to image the production of hyperpolarized propane in a heterogeneous catalytic reactor using both conventional and remote‐detection MRI . Efforts to increase the efficiency of the pairwise addition of hydrogen to unsaturated hydrocarbons by modifying the heterogeneous catalyst structure and varying the nature of catalytically active sites helped identify Rh/TiO 2 as an efficient hydrogenation catalyst for the production of hyperpolarized propane for 3D MRI with microscale spatial resolution (625×625×625 μm 3 ) …”

Section: How To Make Use Of Parahydrogen‐induced Polarization: Contramentioning

confidence: 99%

Parahydrogen‐Based Hyperpolarization for Biomedicine

et al. 2018

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Magnetic resonance (MR) is one of the most versatile and useful physical effects used for human imaging, chemical analysis, and the elucidation of molecular structures. However, its full potential is rarely used, because only a small fraction of the nuclear spin ensemble is polarized, that is, aligned with the applied static magnetic field. Hyperpolarization methods seek other means to increase the polarization and thus the MR signal. A unique source of pure spin order is the entangled singlet spin state of dihydrogen, parahydrogen (pH ), which is inherently stable and long-lived. When brought into contact with another molecule, this "spin order on demand" allows the MR signal to be enhanced by several orders of magnitude. Considerable progress has been made in the past decade in the area of pH -based hyperpolarization techniques for biomedical applications. It is the goal of this Review to provide a selective overview of these developments, covering the areas of spin physics, catalysis, instrumentation, preparation of the contrast agents, and applications.

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The effect of oxidative and reductive treatments of titania-supported metal catalysts on the pairwise hydrogen addition to unsaturated hydrocarbons

Cited by 20 publications

References 34 publications

Heterogeneous ¹H and ¹³C Parahydrogen‐Induced Polarization of Acetate and Pyruvate Esters

Heterogeneous ¹H and ¹³C Parahydrogen‐Induced Polarization of Acetate and Pyruvate Esters

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

Parahydrogen‐Based Hyperpolarization for Biomedicine

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The effect of oxidative and reductive treatments of titania-supported metal catalysts on the pairwise hydrogen addition to unsaturated hydrocarbons

Cited by 20 publications

References 34 publications

Heterogeneous 1H and 13C Parahydrogen‐Induced Polarization of Acetate and Pyruvate Esters

Heterogeneous 1H and 13C Parahydrogen‐Induced Polarization of Acetate and Pyruvate Esters

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

Parahydrogen‐Based Hyperpolarization for Biomedicine

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Product

Resources

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Heterogeneous ¹H and ¹³C Parahydrogen‐Induced Polarization of Acetate and Pyruvate Esters

Heterogeneous ¹H and ¹³C Parahydrogen‐Induced Polarization of Acetate and Pyruvate Esters