<br>通过台式核磁共振波谱监测反应：在线停流和连续流采样方法的实际比较,Magnetic Resonance in Chemistry

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通过台式核磁共振波谱监测反应：在线停流和连续流采样方法的实际比较
Magnetic Resonance in Chemistry ( IF 1.9 ) Pub Date : 2023-09-22 , DOI: 10.1002/mrc.5395
Tristan Maschmeyer _{1,

2} , David J Russell ₂ , José G Napolitano ₂ , Jason E Hein _{1,

3,

4}

Affiliation

核磁共振 (NMR) 光谱能够提供定量、结构丰富的信息，使这种光谱技术成为一种有吸引力的反应监测工具。近年来，随着市售台式 NMR 仪器和兼容流动系统的涌入，NMR 用于此类分析的实用性才有所增加。在本研究中，我们的目的是比较在在线连续流和停流采样方法下获得的¹⁹ F NMR 反应曲线，与现代台式 NMR 仪器和两个反应系统：均相亚胺化反应和双相活化反应。羧酸转化为酰氟。可以通过在线连续流分析获得具有更高数据密度的反应趋势，并且这项工作强调，当监测具有较短自旋晶格弛豫时间（ T ₁ ）的共振时，无需任何校正即可获得代表性反应趋势，并且使用的流动条件。在线停流分析产生了所有情况下的代表性反应趋势，包括监测长T ₁的共振，而不需要任何校正因子。然而，更容易的数据分析的好处是伴随着时间成本，因为新鲜的反应溶液必须流入 NMR 系统，停止，并且必须提供时间让自旋在光谱分析之前在仪器的外部磁场中极化。测量。其中一个反应的结果还与使用高场核磁共振进行了比较。

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Reaction monitoring via benchtop nuclear magnetic resonance spectroscopy: A practical comparison of on-line stopped-flow and continuous-flow sampling methods

The ability for nuclear magnetic resonance (NMR) spectroscopy to provide quantitative, structurally rich information makes this spectroscopic technique an attractive reaction monitoring tool. The practicality of NMR for this type of analysis has only increased in the recent years with the influx of commercially available benchtop NMR instruments and compatible flow systems. In this study, we aim to compare ¹⁹F NMR reaction profiles acquired under both on-line continuous-flow and stopped-flow sampling methods, with modern benchtop NMR instrumentation, and two reaction systems: a homogeneous imination reaction and a biphasic activation of a carboxylic acid to acyl fluoride. Reaction trends with higher data density can be acquired with on-line continuous-flow analyses, and this work highlights that representative reaction trends can be acquired without any correction when monitoring resonances with a shorter spin–lattice relaxation time (T₁), and with the used flow conditions. On-line stopped-flow analyses resulted in representative reaction trends in all cases, including the monitoring of resonances with a long T₁, without the need of any correction factors. The benefit of easier data analysis, however, comes with the cost of time, as the fresh reaction solution must be flowed into the NMR system, halted, and time must be provided for spins to become polarized in the instrument's external magnetic field prior to spectral measurement. Results for one of the reactions were additionally compared with the use of a high-field NMR.

更新日期：2023-09-22

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