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Eingeladener Vortrag
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The project InPROMPT aims to establish a robust hydroformylation reaction process of the alkene n-dodecene to the aldehyde n-tridecanal using a rhodium complex as catalyst in the presence of syngas. This industrial relevant production process demands further research for optimization and expansion. For that purpose, the fiber optic coupled probe of a process Raman spectrometer is directly introduced in the product stream, which enables the recording of spectra within short control intervals.
Die Abtrennung von CO2 aus industriellen Gasströmen ist eine großtechnisch wichtige Trennaufgabe. Neben der Aufarbeitung von Erdgas werden diese Verfahren zur Verminderung der CO2-Emission durch industrielle Rauchgase, insbesondere für alternativlose Prozesse wie die Stahl- und Zementproduktion diskutiert.
Medium resolution nuclear magnetic resonance (MR-NMR) spectroscopy is currently a fast developing field, which has an enormous potential to become an important analytical tool for reaction monitoring, in hyphenated techniques, and for systematic investigations of complex mixtures. The recent developments of innovative MR-NMR spectrometers are therefore remarkable due to their possible applications in quality control, education, and process monitoring. MR-NMR spectroscopy can beneficially be applied for fast, non-invasive, and volume integrating analyses under rough environmental conditions.
Within this study, a simple 1/16'' fluorinated ethylene propylene (FEP) tube with an ID of 0.04'' (1.02 mm) was used as a flow cell in combination with a 5 mm glass Dewar tube inserted into a benchtop MR-NMR spectrometer with a 1H Larmor frequency of 43.32 MHz and 40.68 MHz for 19F. For the first time, quasi-simultaneous proton and fluorine NMR spectra were recorded with a series of alternating 19F and 1H single scan spectra along the reaction time coordinate of a homogeneously catalysed esterification model reaction containing fluorinated compounds. The results were compared to quantitative NMR spectra from a hyphenated 500 MHz online NMR instrument for validation. Automation of handling, pre-processing, and analysis of NMR data becomes increasingly important for process monitoring applications of online NMR spectroscopy and for its technical and practical acceptance. Thus, NMR spectra were automatically baseline corrected and phased using the minimum entropy method. Data analysis schemes were designed such that they are based on simple direct integration or first principle line fitting, with the aim that the analysis directly revealed molar concentrations from the spectra.
Finally, the performance of 1/16'' FEP tube set-up with an ID of 1.02 mm was characterised regarding the limit of detection (LOQ (1H) = 0.335 mol L-1 and LOQ (19F) = 0.130 mol L-1 for trifluoroethanol in D2O (single scan)) and maximum quantitative flow rates up to 0.3 mL min-1. Thus, a series of single scan 19F and 1H NMR spectra acquired with this simple set-up already presents a valuable basis for quantitative reaction monitoring.
Die quantitative NMR-Spektroskopie (qNMR) gewinnt in den letzten Jahren immer mehr an Bedeutung, speziell hinsichtlich der Anwendung auf komplexe Fragestellungen der analytischen Chemie. Ein großer Vorteil dieser Methode ist die Möglichkeit der Relativquantifizierung durch das „Zählen von Kernspins" in der Probe. Unter der Voraussetzung eines korrekt ausgeführten NMR-Experiments ist so der direkte Vergleich von Signalflächen im Spektrum möglich, ohne dass zuvor zwingend eine Kalibrierung notwendig ist.
In der Forschung wird die Kernspinresonanzspektroskopie (NMR-Spektroskopie von englisch: nuclear magnetic resonance) für die Strukturaufklärung und Quantifizierung genutzt. Eine Arbeitsgruppe an der Berliner Bundesanstalt für Materialforschung und -prüfung (BAM) und am Karlsruher Institut für Technologie (KIT) hat die Möglichkeiten untersucht, die NMR-Spektroskopie auch als Online-Methode für das Monitoring chemischer Reaktionen in der Prozesskontrolle einsetzbar zu machen.
Die Entwicklung innovativer Medium-Resolution-NMR-Spektrometer eröffnet eine Reihe bemerkenswerter Applikationen für die Qualitätskontrolle, die akademische Ausbildung und die Prozessanalytik. Die Verwendung von Permanentmagneten erlaubt den Einsatz der NMR-Spektroskopie in industriellen Prozessumgebungen.
Quantitative online NMR spectroscopy of technical mixtures: on the fly quantification of fluids
(2014)
In this paper quantitative NMR spectroscopy is demonstrated as a tool for process analytical technology (PAT) in order to obtain real time information from dynamic processes. Different methods for quantification are presented and as a result the limit of detection for NMR measurement could be determined to 3.3 mg kg-1 (ethanol in water). As model processes esterification reactions and dissolution of pharmaceutical formulations are presented and important process parameters are extracted. Furthermore it is demonstrated that not only 1H-NMR spectroscopy can be used for process monitoring but also 13C-NMR for technical mixtures.