Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor

• Pengcheng Li,
• Daniel Kowalczyk,
• Johannes Liessem,
• Mohamed M. Elnagar,
• Dariusz Mitoraj,
• Radim Beranek and
• Dirk Ziegenbalg

Beilstein J. Org. Chem. 2024, 20, 74–91, doi:10.3762/bjoc.20.9

• intermediates at higher intensities [37]. For further studies, the reactor setup was equipped with four heat sinks around the reactor, each equipped with 6 LEDs. This was the constructive maximum of LEDs that could be installed and allowed for providing a maximum photon flux of 32.77 µmol s−1 to the reactor

• for an overhead stirrer. 3D-printed support structures were used to ensure a reproducible installation for the reactor setup (see Figure 18a). The propellers used to induce the required convection in the draft tube were also 3D-printed. One large propeller was mounted at the bottom of the shaft tube

• ) AQE for differrent photocatalyst loadings and stirring speeds. Reactor design: (a) CAD drawing of the loop reactor, (b) picture of the manufactured loop reactor. Assembled reactor and 3D printed parts: (a) the whole reactor setup, (b) 3D printed propellers. Photocatalytic reaction setup: (a) reaction

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• appropriate in certain contexts of application. Broadly speaking, it can be concluded that carrying out reactions with conPET, both in academia and industry, has a lower barrier of accessibility due to more intuitive/standardized reactor setups. Essentially, the reactor setup can be identical to standard

Shift of the reaction equilibrium at high pressure in the continuous synthesis of neuraminic acid

• Jannis A. Reich,
• Miriam Aßmann,
• Kristin Hölting,
• Paul Bubenheim,
• Jürgen Kuballa and
• Andreas Liese

Beilstein J. Org. Chem. 2022, 18, 567–579, doi:10.3762/bjoc.18.59

• suggests a reduction in molar volume. The circular reactor setup allowed for easy sampling and enabled the analysis of the resulting progress curve. The findings for the epimerase indicate that some inconspicuous reactions, such as the inhibition by pyruvate, can be influenced by pressure. In both

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

Low-budget 3D-printed equipment for continuous flow reactions

• Jochen M. Neumaier,
• Amiera Madani,
• Thomas Klein and
• Thomas Ziegler

Beilstein J. Org. Chem. 2019, 15, 558–566, doi:10.3762/bjoc.15.50

• reactions as a proof of concept for our hardware and for reactor setup. We first started with the optimization of the synthesis of the commonly used glycosyl donor acetobromo-α-D-glucose 2 under flow conditions. To the best of our knowledge, the preparation of glycosyl bromides under continuous flow

Biocatalytic synthesis of the Green Note trans-2-hexenal in a continuous-flow microreactor

• Morten M. C. H. van Schie,
• Tiago Pedroso de Almeida,
• Gabriele Laudadio,
• Florian Tieves,
• Elena Fernández-Fueyo,
• Timothy Noël,
• Isabel W. C. E. Arends and
• Frank Hollmann

Beilstein J. Org. Chem. 2018, 14, 697–703, doi:10.3762/bjoc.14.58

• overcome by conducting the reaction in a flow-reactor setup reaching unpreceded catalytic activities for the enzyme in terms of turnover frequency (up to 38 s−1) and turnover numbers (more than 300000) pointing towards preparative usefulness of the proposed reaction scheme. Keywords: alcohol oxidase

• reactor enzymatic oxidation Next, we performed the PeAAOx-catalysed oxidation of trans-hex-2-enol in a slug-flow reactor setup (Supporting Information File 1, Figure S1 and Figures S9–S11). In a first set of experiments we systematically varied the residence time of the reaction mixture in the flow

Latest development in the synthesis of ursodeoxycholic acid (UDCA): a critical review

• Fabio Tonin and
• Isabel W. C. E. Arends

Beilstein J. Org. Chem. 2018, 14, 470–483, doi:10.3762/bjoc.14.33

• production of UDCA. Different chemical, chemoenzymatic and enzymatic routes will be considered. In addition, the precursors availability as well as the substrate loading in the process and the requisites for potential new routes will be discussed. Furthermore, the potential benefits of a flow reactor setup

Continuous-flow retro-Diels–Alder reaction: an efficient method for the preparation of pyrimidinone derivatives

• Imane Nekkaa,
• Márta Palkó,
• István M. Mándity and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2018, 14, 318–324, doi:10.3762/bjoc.14.20

• were selected on the basis of the solubility of the starting materials. A schematic representation of the flow reactor setup is illustrated in Figure 1. Products 9–14 thus prepared were identified by means of HPLC–MS and NMR spectroscopic analysis. All physical and spectroscopic data of pyrimidinones 9

A concise flow synthesis of indole-3-carboxylic ester and its derivatisation to an auxin mimic

• Marcus Baumann,
• Ian R. Baxendale and
• Fabien Deplante

Beilstein J. Org. Chem. 2017, 13, 2549–2560, doi:10.3762/bjoc.13.251

• cyclisation products 12 and 14, assigned structure of byproduct 15. Synthetic strategy towards desired indole product 8. Initial flow reactor setup for the synthesis of intermediate 11. Coflore ACR setup for the synthesis of intermediate 11. Quenching and work-up of the reaction stream from the Coflore ACR

A flow reactor setup for photochemistry of biphasic gas/liquid reactions

• Josef Schachtner,
• Patrick Bayer and
• Axel Jacobi von Wangelin

Beilstein J. Org. Chem. 2016, 12, 1798–1811, doi:10.3762/bjoc.12.170

• optimization of a given chemical task by proper choice of the general reactor setup and wide variations of the critical reaction and reactor parameters (Scheme 1). An efficient interaction of all three “reagents” will require careful adjustment of the light source, the wall material, the penetration length

• , tubing, pressure valves) and the key parameters (tube diameter, tube length, back pressure, flow rate) and with their mutual interdependencies. We have presented a thorough analysis of critical parts and conditions of a general microflow reactor setup for photochemical reactions and an exemplary

• mM methylene blue in MeCN at rt, irradiation by warm white LEDs. Mutual interdependencies of critical reaction and reactor parameters. Blueprint of the home-built microflow photoreactor; schematic illustration of the reactor setup with a) solvent reservoir, b) substrate solution, c) T valve (BOLA, F

Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids

• Roman Matthessen,
• Jan Fransaer,
• Koen Binnemans and
• Dirk E. De Vos

Beilstein J. Org. Chem. 2014, 10, 2484–2500, doi:10.3762/bjoc.10.260

• possibilities and challenges of implementing other synthetic methodologies. In view of potential industrial application, the choice of reactor setup, electrode type and reaction pathway has a large influence on the sustainability and efficiency of the process. Keywords: carbon dioxide; carboxylic acids

• ; counter electrode reaction; electrocarboxylation mechanism; reactor setup; Introduction Carbon dioxide recycling Implementing sustainable, resource-efficient chemical processes to meet the world’s growing demand for energy and chemicals is one of today’s major challenges. Depletion of fossil resources

• processes have been demonstrated. The sustainable and efficient formation of carboxylic acids from carbon dioxide presents many intriguing challenges. The choice of reactor setup, electrode type and reaction pathway, not only affects the implementation cost but also determines operational characteristics

Integration of enabling methods for the automated flow preparation of piperazine-2-carboxamide

• Richard J. Ingham,
• Claudio Battilocchio,
• Joel M. Hawkins and
• Steven V. Ley

Beilstein J. Org. Chem. 2014, 10, 641–652, doi:10.3762/bjoc.10.56

• – corresponding to one column volume – elapsed after the pump had been manually re-primed. Reactor setup for optimisation reactions. A multi-position valve (V2) was used for collecting samples. Representation of the control sequence for running experiments under a set of conditions. (See Supporting Information

Investigating the continuous synthesis of a nicotinonitrile precursor to nevirapine

• Ashley R. Longstreet,
• Suzanne M. Opalka,
• Brian S. Campbell,
• B. Frank Gupton and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2013, 9, 2570–2578, doi:10.3762/bjoc.9.292

• for formation of 5 starting from acetone and malononitrile. Supporting Information The Supporting Information describes synthesis and characterization data of all substances given in this article, reactor setup, operational details and screening conditions. Supporting Information File 402

Microflow photochemistry: UVC-induced [2 + 2]-photoadditions to furanone in a microcapillary reactor

• Sylvestre Bachollet,
• Kimitada Terao,
• Shin Aida,
• Yasuhiro Nishiyama,
• Kiyomi Kakiuchi and
• Michael Oelgemöller

Beilstein J. Org. Chem. 2013, 9, 2015–2021, doi:10.3762/bjoc.9.237

• characterization purposes and yield determination. The microcapillary reactor setup is shown in Figure 2. UV-transparent fluorinated ethylene propylene copolymer capillary (FEP; outer/inner diameter: 1.6/0.8 mm) was tightly wrapped around a Pyrex glass cylinder (λ ≥ 300 nm; outer diameter: 8.5 cm). A total of 10 m

Continuous flow photocyclization of stilbenes – scalable synthesis of functionalized phenanthrenes and helicenes

• Quentin Lefebvre,
• Marc Jentsch and
• Magnus Rueping

Beilstein J. Org. Chem. 2013, 9, 1883–1890, doi:10.3762/bjoc.9.221

• ) could be converted to phenanthrene (2a) in 95% NMR yield with a retention time of 83 min (Table 1, entry 5). The flow-reactor setup used for the optimization (Table 1) is shown in Figure 1. UV-transparent ethylene propylene copolymer capillary (FEP, outer/inner diameter 1/0.5 mm, total volume 5 mL) was

• substitution patterns are obtained in good to excellent yields. In addition our first attempts to scale up the flow photocyclization reactions were successful providing the opportunity for multi-gram syntheses. Flow-reactor setup used in the optimization study. Photocyclization of stilbene to phenanthrene

Camera-enabled techniques for organic synthesis

• Steven V. Ley,
• Richard J. Ingham,
• Matthew O’Brien and
• Duncan L. Browne

Beilstein J. Org. Chem. 2013, 9, 1051–1072, doi:10.3762/bjoc.9.118

• , such as the length of tubing used and the residence time required to effect a complete reaction. For subsequent work using oxygen gas, we moved to a more elegant but still simple tube-in-tube reactor setup [79]; in this case the oxidation of a lilac solution of vanadium(II) was used to indicate the

• number of ways. Digital video recordings of reactions can be useful for recording a procedure, for capturing images at high speed or outside the visible regions of the spectrum. In more advanced cases, a digital camera can record a long reaction for later review, or provide visual access to a reactor

• setup that might not otherwise be available. Suzuki–Miyaura reaction performed within a microfluidic system. The product is observed by high-speed microscope photography, which shows a precipitate forming within the microdroplets. Friedel–Crafts reactions performed by using solid-acid catalysis at high

Photochemistry with laser radiation in condensed phase using miniaturized photoreactors

• Elke Bremus-Köbberling,
• Arnold Gillner,
• Frank Avemaria,
• Céline Réthoré and
• Stefan Bräse

Beilstein J. Org. Chem. 2012, 8, 1213–1218, doi:10.3762/bjoc.8.135

• : Description of the flow reactor setup, kinetics, experimental procedures and spectroscopic data of all compounds. Acknowledgements We thank the Fonds der Chemischen Industrie for financial support.

Continuous proline catalysis via leaching of solid proline

• Suzanne M. Opalka,
• Ashley R. Longstreet and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2011, 7, 1671–1679, doi:10.3762/bjoc.7.197

• combined with nitrosobenzene in the coil, the desired product was not detected by crude 1H NMR analysis (Table 1, entry 1). This indicates that, with this reactor setup, the reaction is too slow without a urea additive to be a viable method. Additionally, flowing thiourea 3b (0.047 M in EtOAc) through the

• range of other catalysts by replacing proline with another solid catalyst precursor. We are currently investigating the combination of ligands and solid metal salts to generate transition-metal catalysts continuously. Methods for catalyst use in flow. General reactor setup. A) A glass Omnifit column is

• collection. Schematic of the reactor setup. As the starting aldehyde and thiourea 3b (A) enter the proline packed-bed (B) an oxazolidinone intermediate is formed, drawing the proline into the solution (C). Upon precooling in a reactor coil (E) the intermediate is mixed with nitrosobenzene (D). Prior to

Continuous flow photolysis of aryl azides: Preparation of 3H-azepinones

• Farhan R. Bou-Hamdan,
• François Lévesque,
• Alexander G. O'Brien and
• Peter H. Seeberger

Beilstein J. Org. Chem. 2011, 7, 1124–1129, doi:10.3762/bjoc.7.129

• . General conditions for the photolysis of aryl azides in continuous flow. Effect of aryl azide concentration on conversion. 3H-azepinone derivatives prepared by photolysis of aryl azides in continuous flow. Supporting Information Supporting Information File 188: Description of the flow reactor setup

Flow through reactors for organic chemistry: directly electrically heated tubular mini reactors as an enabling technology for organic synthesis

• Ulrich Kunz and
• Thomas Turek

Beilstein J. Org. Chem. 2009, 5, No. 70, doi:10.3762/bjoc.5.70

• reactor current connector. Supporting Information File 103: Photograph of the preheater connection. Supporting Information File 104: Photograph of the reactor setup. Supporting Information File 105: Photograph of the thermocouple connection. Supporting Information File 106: Photograph of different tubular