An integrated resource-efficient microfluidic device for parallelised studies of immobilised chiral catalysts in continuous flow <i>via</i> miniaturized LC/MS-analysis

Westphal, Hannes; Warias, Rico; Weise, Chris; Ragno, Daniele; Becker, Holger; Spanka, Matthias; Massi, Alessandro; Gläser, Roger; Schneider, Christoph; Belder, Detlev

doi:10.1039/d2re00153e

Cited by 4 publications

(5 citation statements)

References 59 publications

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“…At this stage of the study, driven by our interest in process intensification by the application of flow techniques [ 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 ], we next investigated the transition of the model carbonation of styrene oxide from batch to segmented flow conditions [ 89 , 90 ]. The in-house assembled flow apparatus consisted of a 4.42 mL spiral capillary reactor (FEP tubing; 0.75 mm ID) placed inside a thermostated bath (75 °C).…”

Section: Resultsmentioning

confidence: 99%

Efficiency in Carbon Dioxide Fixation into Cyclic Carbonates: Operating Bifunctional Polyhydroxylated Pyridinium Organocatalysts in Segmented Flow Conditions

et al. 2023

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Novel polyhydroxylated ammonium, imidazolium, and pyridinium salt organocatalysts were prepared through N-alkylation sequences using glycidol as the key precursor. The most active pyridinium iodide catalyst effectively promoted the carbonation of a set of terminal epoxides (80 to >95% yields) at a low catalyst loading (5 mol%), ambient pressure of CO2, and moderate temperature (75 °C) in batch operations, also demonstrating high recyclability and simple downstream separation from the reaction mixture. Moving from batch to segmented flow conditions with the operation of thermostated (75 °C) and pressurized (8.5 atm) home-made reactors significantly reduced the process time (from hours to seconds), increasing the process productivity up to 20.1 mmol(product) h−1 mmol(cat)−1, a value ~17 times higher than that in batch mode.

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Section: Resultsmentioning

confidence: 99%

Efficiency in Carbon Dioxide Fixation into Cyclic Carbonates: Operating Bifunctional Polyhydroxylated Pyridinium Organocatalysts in Segmented Flow Conditions

et al. 2023

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“…The full‐body glass chip (Borofloat 33; dimensions: 22 mm length, 10 mm width, 2 mm depth) used for the present experiments was manufactured by IX‐factory (now: Micronit, Dortmund, Germany; the design was a modification of a previous version). After manufacturing, a monolithic pyramidal nano‐electrospray emitter was ground at the reactor outlet and subsequently hydrophobized [29] . Generally, the chip can be used as a microreactor or for mixing different compounds and enables direct electrospray MS‐hyphenation for online detection.…”

Section: Methodsmentioning

confidence: 99%

“…After manufacturing, a monolithic pyramidal nano-electrospray emitter was ground at the reactor outlet and subsequently hydrophobized. [29] Generally, the chip can be used as a microreactor or for mixing different compounds and enables direct electrospray MS-hyphenation for online detection. The two front inlets were used for introducing analyte solutions by syringe pumps (Nemesys low-pressure pumps, Cetoni, DE).…”

Section: Microfluidic Chip Reactormentioning

confidence: 99%

Online‐Monitoring of the Enantiomeric Ratio in Microfluidic Chip Reactors Using Chiral Selector Ion Vibrational Spectroscopy

Schmahl,

Horn,

Jin

et al. 2024

ChemPhysChem

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A novel experimental approach for the rapid online monitoring of the enantiomeric ratio of chiral analytes in solution is presented. The charged analyte is transferred to the gas phase by electrospray. Diastereomeric complexes are formed with a volatile chiral selector in a buffer‐gas‐filled ion guide held at room temperature, mass‐selected, and subsequently spectrally differentiated by cryogenic ion trap vibrational spectroscopy. Based on the spectra of the pure complexes in a small diastereomer‐specific spectral range, the composition of diastereomeric mixtures is characterized using the cosine similarity score, from which the enantiomeric ratio in the solution is determined. The method is demonstrated for acidified alanine solutions and using three different chiral selectors (2‐butanol, 1‐phenylethanol, 1‐amino‐2‐propanol). Among these, 2‐butanol is the best choice as a selector for protonated alanine, also because the formation ratio of the corresponding diastereomeric complexes is found to be independent of the nature of the enantiomer. Subsequently, a microfluidic chip is implemented to mix enantiomerically pure alanine solutions continuously and determine the enantiomeric ratio online with minimal sample consumption within one minute and with competitive accuracy.

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“…We recently investigated biotransformations in a digital microfluidic (DMF) approach. 66 Building on our previous work with various integrated microfluidic devices for studying immobilised organocatalysts, [67][68][69] we have now transitioned these biotransformations into a microflow platform, leading to improved automation, reactor control, and expanded applications in biocatalytic processes. We used the vanadium-dependent haloperoxidase (CiVHPO) from the fungus Curvularia inaequalis as a model enzyme for evaluating a biocatalytic bromination reaction.…”

Section: Introductionmentioning

confidence: 99%

Development of an automated platform for monitoring microfluidic reactors through multi-reactor integration and online (chip-)LC/MS-detection

Westphal,

Schmidt,

Lama

et al. 2024

Preprint

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This work presents a novel microfluidic screening setup with real-time analytics for investigating reactions with immobilised biocatalysts. The setup combines microreactor technology, multi-reactor integration, and online (chip-)LC/MS analysis in a sequential automated workflow. We utilized in-house manufactured fused-silica glass chips as reusable packed-bed microreactors interconnected as individual tube reactors. The potential of this setup was showcased by conducting and optimising a biocatalytic aromatic bromination reaction as the first proof of concept using immobilised vanadium-dependent haloperoxidase from Curvularia inaequalis (CiVHPO). The fusion of a HaloTagTM to CiVHPO was used for efficient and mild covalent linkage of the enzyme onto chloroalkane-functionalized particles. Then, the biotransformation was continuously monitored with automated LC/MS data acquisition in a data-rich manner. By further developing the automation principle, it was possible to sequentially screen multiple different connected packed-bed microreactors for reaction optimization while using only miniature amounts of reactants and biocatalyst. Finally, we present a fast and modular chipHPLC solution for online analysis to reduce the overall solvent consumption by over 80%. We established a modern microfluidic platform for real-time reaction monitoring and evaluation of biocatalytic reactions through automation of the reactant feed integration, flexible microreactor selection, and online LC/MS analysis.

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An integrated resource-efficient microfluidic device for parallelised studies of immobilised chiral catalysts in continuous flow via miniaturized LC/MS-analysis

Abstract: A highly integrated microfluidic device is presented for the parallelised study of stereoselective heterogeneous catalytic processes. For the first time, multiple packed-bed µ-flow reactors are combined with a chiral separation...

Cited by 4 publications

References 59 publications

Efficiency in Carbon Dioxide Fixation into Cyclic Carbonates: Operating Bifunctional Polyhydroxylated Pyridinium Organocatalysts in Segmented Flow Conditions

Efficiency in Carbon Dioxide Fixation into Cyclic Carbonates: Operating Bifunctional Polyhydroxylated Pyridinium Organocatalysts in Segmented Flow Conditions

Online‐Monitoring of the Enantiomeric Ratio in Microfluidic Chip Reactors Using Chiral Selector Ion Vibrational Spectroscopy

Development of an automated platform for monitoring microfluidic reactors through multi-reactor integration and online (chip-)LC/MS-detection

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