Real-Time Detection of Intermediates in Rhodium-Catalyzed Hydrogenation of Alkynes and Alkenes by Dissolution DNP

Boeg, Peter Andreas; Duus, Jens Øllgaard; Ardenkjær-Larsen, Jan Henrik; Karlsson, Magnus; Mossin, Susanne

doi:10.1021/acs.jpcc.9b01376

Cited by 22 publications

(19 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure ), implying that the dimethyl maleate molecule which was just formed on the catalytic center and still remains bound to the catalyst has a larger probability to be hydrogenated further to dimethyl succinate before it is kicked out from the catalyst by a DMAD molecule. The onset of dimethyl succinate formation quite early in the DMAD hydrogenation reaction was observed, for instance, in a recent NMR study which used DMAD hyperpolarized by dissolution DNP . The DMAD/catalyst ratio in that study was around 5‐fold lower compared to our work, and besides the catalyst was undergoing activation during the measurements.…”

Section: Resultssupporting

confidence: 41%

Chemical Reaction Monitoring using Zero‐Field Nuclear Magnetic Resonance Enables Study of Heterogeneous Samples in Metal Containers

et al. 2020

View full text Add to dashboard Cite

We demonstrate that heterogeneous/biphasic chemical reactions can be monitored with high spectroscopic resolution using zero‐field nuclear magnetic resonance spectroscopy. This is possible because magnetic susceptibility broadening is negligible at ultralow magnetic fields. We show the two‐step hydrogenation of dimethyl acetylenedicarboxylate with para‐enriched hydrogen gas in conventional glass NMR tubes, as well as in a titanium tube. The low frequency zero‐field NMR signals ensure that there is no significant signal attenuation arising from shielding by the electrically conductive sample container. This method paves the way for in situ monitoring of reactions in complex heterogeneous multiphase systems and in reactors made of conductive materials while maintaining resolution and chemical specificity.

show abstract

Section: Resultssupporting

confidence: 41%

Chemical Reaction Monitoring using Zero‐Field Nuclear Magnetic Resonance Enables Study of Heterogeneous Samples in Metal Containers

et al. 2020

View full text Add to dashboard Cite

show abstract

“…4), implying that the dimethyl maleate molecule which was just formed on the catalytic center and still remains bound to the catalyst has a larger probability to be hydrogenated further to dimethyl succinate before it is kicked out from the catalyst by a DMAD molecule. The onset of dimethyl succinate formation quite early in the DMAD hydrogenation reaction was observed, for instance, in a recent NMR study which used DMAD hyperpolarized by dissolution DNP [60]. The DMAD/catalyst ratio in that study was ca.…”

Section: Resultsmentioning

confidence: 75%

Chemical Reaction Monitoring Using Zero-Field Nuclear Magnetic Resonance Enables Study of Heterogeneous Samples in Metal Containers

Burueva¹,

Eills²,

Blanchard³

et al. 2020

Preprint

View full text Add to dashboard Cite

<div> <p>We demonstrate that heterogeneous/biphasic chemical reactions can be monitored with high spectroscopic resolution using zero-field nuclear magnetic resonance. This is possible because magnetic susceptibility broadening is insignificant at ultralow magnetic fields. We show the two-step hydrogenation of dimethyl acetylenedicarboxylate with <i>para</i>-enriched hydrogen gas in conventional glass NMR tubes, as well as in a titanium tube. The low frequency zero-field NMR signals ensure that there is no significant signal attenuation due to shielding by the electrically conductive sample container. This method paves the way for <i>in situ</i> monitoring of reactions in complex heterogeneous multiphase systems and in reactors made from conductive materials without magnetic susceptibility induced line broadening.</p></div>

show abstract

“…It rapidly dissolves the sample and pushes it through a capillary to the detection spectrometer. One can thus achieve signal enhancements in liquid-state NMR of 4 orders of magnitude Capitalizing on the resulting improved sensitivity, DDNP has found various applications in recent years, including real-time metabolomics (Liu and Hilty, 2018;Sadet et al, 2018), reaction monitoring (Boeg et al, 2019), structural biology (Szekely et al, 2018;Wang and Hilty, 2019), and detection of long-lived spin states (Tayler et al, 2012;Bornet et al, 2014). However, DDNP instrumentation is still actively being developed to improve its cost efficiency and reliability, and a need for user-friendly DDNP systems persists.…”

Section: Introductionmentioning

confidence: 99%

A novel sample handling system for dissolution dynamic nuclear polarization experiments

et al. 2021

View full text Add to dashboard Cite

Abstract. We present a system for facilitated sample vitrification, melting, and transfer in dissolution dynamic nuclear polarization (DDNP) experiments. In DDNP, a sample is typically hyperpolarized at cryogenic temperatures before dissolution with hot solvent and transfer to a nuclear magnetic resonance (NMR) spectrometer for detection in the liquid state. The resulting signal enhancements can exceed 4 orders of magnitude. However, the sudden temperature jump from cryogenic temperatures close to 1 K to ambient conditions imposes a particular challenge. It is necessary to rapidly melt the sample to avoid a prohibitively fast decay of hyperpolarization. Here, we demonstrate a sample dissolution method that facilitates the temperature jump by eliminating the need to open the cryostat used to cool the sample. This is achieved by inserting the sample through an airlock in combination with a dedicated dissolution system that is inserted through the same airlock shortly before the melting event. The advantages are threefold: (1) the cryostat can be operated continuously at low temperatures. (2) The melting process is rapid as no pressurization steps of the cryostat are required. (3) Blockages of the dissolution system due to freezing of solvents during melting and transfer are minimized.

show abstract

Real-Time Detection of Intermediates in Rhodium-Catalyzed Hydrogenation of Alkynes and Alkenes by Dissolution DNP

Cited by 22 publications

References 19 publications

Chemical Reaction Monitoring using Zero‐Field Nuclear Magnetic Resonance Enables Study of Heterogeneous Samples in Metal Containers

Chemical Reaction Monitoring using Zero‐Field Nuclear Magnetic Resonance Enables Study of Heterogeneous Samples in Metal Containers

Chemical Reaction Monitoring Using Zero-Field Nuclear Magnetic Resonance Enables Study of Heterogeneous Samples in Metal Containers

A novel sample handling system for dissolution dynamic nuclear polarization experiments

Contact Info

Product

Resources

About