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Search for "microreactor" in Full Text gives 78 result(s) in Beilstein Journal of Organic Chemistry.
Continuous-flow processes for the catalytic partial hydrogenation reaction of alkynes
Beilstein J. Org. Chem. 2017, 13, 734–754, doi:10.3762/bjoc.13.73
- for a capillary microreactor (10 m length, 250 μm i.d., 110 nm film thickness) operating under annular two-phase flow regime, and whose inner walls were coated with a bimetallic Pd25Zn75 catalyst onto mesoporous TiO2 (Table 1, entry 10). Selectivity could be further improved (97%) by addition of
- process), thereby favouring further reaction with H2 and reducing selectivity. In bulky ligand-modified catalysts, such as Pd(HHDMA)@C, the adsorption process is slightly endothermic and selectivity is enhanced. A high yield of 4a (78%) was also obtained by means of a capillary microreactor consisting in
Contribution of microreactor technology and flow chemistry to the development of green and sustainable synthesis
Beilstein J. Org. Chem. 2017, 13, 520–542, doi:10.3762/bjoc.13.51
- Flavio Fanelli Giovanna Parisi Leonardo Degennaro Renzo Luisi Department of Pharmacy – Drug Sciences, University of Bari “A. Moro”, FLAME-Lab – Flow Chemistry and Microreactor Technology Laboratory, Via E. Orabona 4, 70125, Bari. Italy 10.3762/bjoc.13.51 Abstract Microreactor technology and flow
- chemistry could play in the near future for a sustainable development. Keywords: flash chemistry; flow chemistry; green chemistry; microreactor technology; sustainable synthesis; Introduction Green chemistry’s birth was driven by the necessity to consider and face the urgent question of sustainability
- chemistry we can read Paul Anastas and John Warne’s 12 principles, set up in 1998, which illustrate the characteristics of a greener chemical process or product [2]. Microreactor technology and flow chemistry could play a pivotal role in the context of sustainable development. In fact, flow chemistry is
A chemoselective and continuous synthesis of m-sulfamoylbenzamide analogues
Beilstein J. Org. Chem. 2017, 13, 303–312, doi:10.3762/bjoc.13.33
- selectivity are obtained for a flow rate of 125 µL/min for starting materials 1 and 2a and 250 µL/min for reactant 2b. The temperature for the first microreactor was kept at 20 °C to avoid coupling with the sulfonyl chloride. The second reactor was kept at 40 °C. This increase in temperature enables the
NMR reaction monitoring in flow synthesis
Beilstein J. Org. Chem. 2017, 13, 285–300, doi:10.3762/bjoc.13.31
- planning, interpreting results and developing new projects. In this regard, flow chemistry is the central motif of this automated approach. In contrast to batch mode, in flow chemistry the starting materials are continuously introduced into the flow reactor (e.g., a microreactor or a column) and the
- the production scale for quality control, the coupling of flow and microreactor technology with a good analytical method is a prerequisite. Several analytical methods have been used and these include fluorescence, ultraviolet–visible (UV–vis), RAMAN, infrared (IR) and nuclear magnetic resonance (NMR
- ) spectroscopy and mass spectrometry (MS). The use of a particular technique depends on the application, on the characteristics of the analyte and the ease of coupling with the flow system [11][12]. In this paper we focus on the coupling of nuclear magnetic resonance spectroscopy with flow and microreactor
Continuous-flow synthesis of highly functionalized imidazo-oxadiazoles facilitated by microfluidic extraction
Beilstein J. Org. Chem. 2017, 13, 239–246, doi:10.3762/bjoc.13.26
- ; microreactor; 1,2,4-oxadiazole; Introduction The design and execution of scalable and economically viable processes for the preparation of biologically active small molecules is a major hurdle in modern organic synthesis. The development of batch processes that combine multiple reactions into “one-pot” have
- , three-microreactor method for the highly efficient preparation of a diverse library of imidazo-oxadiazole derivatives. Moreover, this continuous-flow method was successfully combined with a single-step liquid–liquid microextraction unit to remove high boiling point polar solvents and impurities. Results
- reaction conditions using a single microreactor we found that the combination of EDC/HOBt/DIPEA (1:1:1) for 10 min at 150 °C provided the best conditions for complete conversion of 3-bromobenzoic acid to the corresponding 1,2,4-oxadiazole derivative (Table 1, entry 5). The use of N,N-dimethylformamide (DMF
Self-optimisation and model-based design of experiments for developing a C–H activation flow process
Beilstein J. Org. Chem. 2017, 13, 150–163, doi:10.3762/bjoc.13.18
- the basis of an automated microreactor experimental system for several complex reactions [8][12][13]. The framework uses factorial design of experiments to obtain an initial data set for parameter estimation, followed by an iterative search with online model discrimination and parameter estimation
Electron-transfer-initiated benzoin- and Stetter-like reactions in packed-bed reactors for process intensification
Beilstein J. Org. Chem. 2016, 12, 2719–2730, doi:10.3762/bjoc.12.268
- -reaction phase and improving NHCs’ stability towards air and moisture [10][11]. Quite surprisingly, however, implementation of continuos-flow techniques with micro- and meso-reactors is rare in this field [12][13][14][15][16][17]. Indeed, microreactor technology is today a powerful tool for the fine
- -diphenylethen-1,2 diol (11) in 6% isolated yield (Scheme 2). At this stage of our investigation, PS-BEMP 5 was tested as the packing material of fixed-bed reactors with potential long-term stability. A micro-HPLC with minimized extra-column volumes was used as the pumping system. The fixed-bed microreactor R5
- substrates and a flow rate of 10 μL min−1 (81% conversion; Table 4, entry 1), operating the microreactor R5 at a lower flow rate (5 μL min−1; residence time: 276 min) guaranteed the complete consumption of the reactants (Table 4, entry 2). Under these conditions, the benzoylated benzoin product 3aa could be
Continuous-flow synthesis of primary amines: Metal-free reduction of aliphatic and aromatic nitro derivatives with trichlorosilane
Beilstein J. Org. Chem. 2016, 12, 2614–2619, doi:10.3762/bjoc.12.257
- base (3.6 mmol) in dry CH2Cl2 (1.5 mL). Syringes A and B were connected to a syringe pump and the reagents were pumped into the microreactor at the indicated flow rate (mL/min) at room temperature. The outcome of the reactor was collected in a flask containing a 10% NaOH solution. Five reactor volumes
The in situ generation and reactive quench of diazonium compounds in the synthesis of azo compounds in microreactors
Beilstein J. Org. Chem. 2016, 12, 1987–2004, doi:10.3762/bjoc.12.186
- reaction conversions ranging between 66–91% were attained. Keywords: azo coupling; diazotization; microreactor; scale up; Introduction Going green, a familiar catch phrase in the chemical industry, in addition to environment protection laws have influenced and also triggered the development of cleaner
- be changed or modified to achieve the above mentioned green benefits in addition to other advantages. For example, isolated diazonium salts are known to be hazardous due to their explosive and unstable nature. However, microreactor technology makes it possible to safely perform reactions with
- the conventional way of performing reactions, the amount of waste generated is dealt with at the end of the reaction. On the contrary, microreactor technology enables the reduction of waste generated by increasing the atom efficiency of reactions and in so doing, the quantity of starting materials is
A flow reactor setup for photochemistry of biphasic gas/liquid reactions
Beilstein J. Org. Chem. 2016, 12, 1798–1811, doi:10.3762/bjoc.12.170
- Josef Schachtner Patrick Bayer Axel Jacobi von Wangelin Institute of Organic Chemistry, University of Regensburg, Universitaetsstr. 31, 93040 Regensburg, Germany 10.3762/bjoc.12.170 Abstract A home-built microreactor system for light-mediated biphasic gas/liquid reactions was assembled from
- described set-up operates residence times of up to 30 min which cover the typical rates of many organic reactions. The tubular microreactor was successfully applied to the photooxygenation of hydrocarbons (Schenck ene reaction). Major emphasis was laid on the realization of a constant and highly
- operation of various other reactions at light/liquid/gas interfaces in student, research, and industrial laboratories. Keywords: biphasic reactions; flow chemistry; gas phase; microreactor; oxygen; photochemistry; Introduction The recent developments of microreactor technologies have significantly
Scope and mechanism of the highly stereoselective metal-mediated domino aldol reactions of enolates with aldehydes
Beilstein J. Org. Chem. 2016, 12, 813–824, doi:10.3762/bjoc.12.80
- a decrease of the yield compared with 5a (Scheme 5, Table 7). The best yields were obtained within a series in the case of ketone and aldehyde possessing a donor–acceptor situation. Domino aldol reaction by using a CYTOS™ microreactor Using the CYTOS™ microreactor, a continuous reactor, the
Enabling technologies and green processes in cyclodextrin chemistry
Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30
- miniaturized continuous flow reactor, also called microreactor, offers many advantages over conventional scale reactors, including considerable improved energy exploitation, increased reaction speed and yield, safety, reliability, scalability, on-site/on-demand production, etc., and a much finer degree of
- process control. However microreactors do not tolerate mechanical inhomogeneities. To resolve the problem of microparticles, which often cause clogging, a second generation of microreactors has been developed and called microjetreactor [99]. A typical microreactor is made up of a 'sandwich' of thin metal
- Vijayalakshmi have pointed out the theoretical use of enzymes in the production of CDs or other cyclic oligosaccharides, like cyclofructan, rather than using a microreactor [104]. Conclusion Dynamic intrusion of the enabling technologies to the CD chemistry is inevitable and shows exponential growth. Although
Carbon–carbon bond cleavage for Cu-mediated aromatic trifluoromethylations and pentafluoroethylations
Beilstein J. Org. Chem. 2015, 11, 2661–2670, doi:10.3762/bjoc.11.286
- reaction temperature from 160 °C to 200 °C accelerated the decarboxylation of CF3CO2K [36] (Scheme 3). The trifluoromethylation using a microreactor resulted in a good yield within a short reaction time by virtue of the thermal stability of CF3Cu and control of mixing. Taking advantage of the flow
- microreactor, a new protocol for scalable aromatic trifluoromethylation was developed. From a mechanistic aspect, Vicic and co-workers explored the direct generation of CF3Cu from CF3CO2Cu. The use of (N-heterocyclic carbene)copper-trifluoroacetates prepared from trifluoroacetic acid (TFA) was investigated in
The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry
Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134
- hydroxamic acid (5, SAHA, Figure 1) [43]. Another early application of microreactor technology was reported in 2005 detailing the assembly and subsequent decoration of the fluoroquinolinone scaffold 6 resulting in the synthesis of a library of analogues including the well-known antibiotic ciprofloxacin (6
- step approach towards ibuprofen (16) using microreactor technology [48]. A fully continuous process was aspired to, in which only final purification was to be performed off-line at the end of the sequence. Each of the individual steps were first optimised in flow being mindful of the reagents used in
- concept of photons and the ability to overcome the inherent dilution problems encountered in batch. The ability to control residence times and hence decrease secondary transformations whilst using the small dimensions of the microreactor flow streams to enhance the photon flux has been claimed to increase
Synthesis and immunological evaluation of protein conjugates of Neisseria meningitidis X capsular polysaccharide fragments
Beilstein J. Org. Chem. 2014, 10, 2367–2376, doi:10.3762/bjoc.10.247
- salicylchlorophosphite in CH3CN, respectively, were pumped in a 100 μL glass microreactor. The device was completed by a reservoir connected to the outlet of the microreactor, refilled with a solution of triethylammonium bicarbonate buffer (TEAB) 1.0 M to stabilize the H-phosphonate product. Setting the residence time
- fragments, based on the synthetic improvements and also the benefits of the continuous-flow microreactor technology herein described, is currently ongoing in our laboratory and it will be reported in due course. Besides the length of the carbohydrate haptens, the saccharide loading onto the protein is
Visible light photoredox-catalyzed deoxygenation of alcohols
Beilstein J. Org. Chem. 2014, 10, 2157–2165, doi:10.3762/bjoc.10.223
- microreactor (see Supporting Information File 1). Conclusion In summary a protocol for the deoxygenation of benzylic alcohols, α-hydroxycarbonyl and α-cyanohydrin compounds under visible light photocatalysis was developed using 3,5-bis(trifluoromethyl)benzoic anhydride for alcohol activation. Since 3,5-bis
A new charge-tagged proline-based organocatalyst for mechanistic studies using electrospray mass spectrometry
Beilstein J. Org. Chem. 2014, 10, 2027–2037, doi:10.3762/bjoc.10.211
- temporal evolution has been followed using a microreactor continuous-flow technique. Keywords: charge tag; electrospray; mass spectrometry; organocatalysis; proline; template; Introduction Electrospray ionization (ESI) mass spectrometry [1] has not only developed into a standard characterization method
- both reactions by ESIMS. These so-called continuous-flow experiments [5][20] allow the sampling of reaction times down to seconds. Solutions of the reagents are mixed in the first microreactor and diluted to concentrations suitable for ESIMS in the second microreactor. The reaction time between the
Continuous flow nitration in miniaturized devices
Beilstein J. Org. Chem. 2014, 10, 405–424, doi:10.3762/bjoc.10.38
- followed by a coiled capillary (length ~30 cm and 180 cm, i.d. ~0.127 mm to 0.3 mm), which served as a microreactor system. The reactor coil was placed on a hot plate that was insulated with layers of polyurethane foam to ensure a minimum heat loss. The experimental setup resembles the schematic shown in
- , the initial reaction rates are reported to be higher when the inlet velocity of the reacting mixture is increased, a fact later elaborated in detail by Dummann et al. [43]. Continuous flow nitration of a few important arenes using the standard nitrating mixture in a CYTOS microreactor was carried out
- process required only 0.8 minutes at 3 °C to obtain 70% yield of the desired nitro derivative. For the nitration of pyridine N-oxide (6), which requires a higher temperature (~120 °C), the approach using a microreactor resulted in a yield of 78%, an improvement compared to the conventional approach (72
Flow microreactor synthesis in organo-fluorine chemistry
Beilstein J. Org. Chem. 2013, 9, 2793–2802, doi:10.3762/bjoc.9.314
- faced with problems such as the difficulties in handling of fluorinating reagents and in controlling of chemical reactions. Recently, flow microreactor synthesis has emerged as a new methodology for producing chemical substances with high efficiency. This review outlines the successful examples of
- synthesis and reactions of fluorine-containing molecules by the use of flow microreactor systems to overcome long-standing problems in fluorine chemistry. Keywords: defluorination; fluorine; fluorination; flow microreactor; organo-fluorine; perfluoroalkylation; Review Fluorine is a key element in the
- fluorine chemistry. Meanwhile, flow microreactor synthesis, the use of microfluidic devices, has emerged as a new method for producing chemical substances with high efficiency [11][12][13]. Now, the introduction of continuous-flow synthesis technique to laboratory synthesis represents a highly useful and
A combined continuous microflow photochemistry and asymmetric organocatalysis approach for the enantioselective synthesis of tetrahydroquinolines
Beilstein J. Org. Chem. 2013, 9, 2457–2462, doi:10.3762/bjoc.9.284
- ][11][12][13][14][15][16][17]. In the past years, continuous-flow chemistry has received considerable attention and microstructured continuous-flow devices have emerged as useful devices for different chemical reactions [18][19][20][21][22]. Microreactor technology offers numerous practical advantages
- such as better reaction yield due to enhanced mixing quality, better control of reaction variables, reduced safety hazards, reduced reagent consumption, enhanced heat and mass transfer due to the high surface-to-volume ratio and rapid experimentation and optimization. Recently, microreactor devices
- ] could provide the desired enantioenriched tetrahydroquinolines (Scheme 1) [38]. Results and Discussion The continuous-flow microreactor system for the experiment was set up according to Scheme 2. The flow device was set up with multiple commercially available glass reactors connected in parallel and
Flow synthesis of phenylserine using threonine aldolase immobilized on Eupergit support
Beilstein J. Org. Chem. 2013, 9, 2168–2179, doi:10.3762/bjoc.9.254
- aldolase (TA) from Thermotoga maritima was immobilized on an Eupergit support by both a direct and an indirect method. The incubation time for the direct immobilization method was optimized for the highest amount of enzyme on the support. By introducing the immobilized TA in a packed-bed microreactor, a
- , there is indication that biocatalysis under flow conditions provided by a microreactor can result in better process control by external numbering-up in which each subunit of reaction can be examined separately with enhanced productivity [11]. Microreactors have been used in many fields of chemistry such
- support. In continuation of our previous work [48], this paper includes further investigation of the thermal stability of TA on Eupergit by a so-called direct and indirect method. Also, a flow synthesis of Eupergit-immobilized TA in a packed bed microreactor was established and compared to the use of free
Microflow photochemistry: UVC-induced [2 + 2]-photoadditions to furanone in a microcapillary reactor
Beilstein J. Org. Chem. 2013, 9, 2015–2021, doi:10.3762/bjoc.9.237
- was connected to a shut-valve attached to a 10 mL syringe, whereas the outlet was inserted into an amber round-bottom flask outside the chamber reactor. The reaction mixture was loaded into the syringe, degassed with nitrogen, pumped through the microreactor at a given flow rate and collected in an
One-step synthesis of pyridines and dihydropyridines in a continuous flow microwave reactor
Beilstein J. Org. Chem. 2013, 9, 1957–1968, doi:10.3762/bjoc.9.232
- by Kappe, Kunz and Kirschning revealed that continuous flow processing gave better conversions and improved catalyst recycling, with no loss of activity [26]. A range of other applications have been explored, from a continuous flow isothermal narrow channel microreactor for process intensification of
Ethyl diazoacetate synthesis in flow
Beilstein J. Org. Chem. 2013, 9, 1813–1818, doi:10.3762/bjoc.9.211
- used on lab scale. Its highly explosive nature, however, severely limits its use in industrial processes. The in-line coupling of microreactor synthesis and separation technology enables the synthesis of this compound in an inherently safe manner, thereby making it available on demand in sufficient
- conditions, a production yield of 20 g EDA day−1 was achieved using a microreactor with an internal volume of 100 μL. Straightforward scale-up or scale-out of microreactor technology renders this method viable for industrial application. Keywords: diazo compounds; diazotization; ethyl diazoacetate (EDA
- ); flow chemistry; microreactor technology; Introduction Diazo compounds are frequently used versatile building blocks in organic chemistry [1][2]. From this class of compounds diazomethane and ethyl diazoacetate (1, EDA) are arguably the synthetically most useful ones. Due to the potentially explosive
Flow Giese reaction using cyanoborohydride as a radical mediator
Beilstein J. Org. Chem. 2013, 9, 1791–1796, doi:10.3762/bjoc.9.208
- precursors, ethyl acrylate as a radical trap, and sodium cyanoborohydride as a radical mediator, were examined in a continuous flow system. With the use of an automated flow microreactor, flow reaction conditions for the Giese reaction were quickly optimized, and it was found that a reaction temperature of
- 70 °C in combination with a residence time of 10–15 minutes gave good yields of the desired addition products. Keywords: continuous flow system; cyanoborohydride; flow chemistry; iodoalkanes; microreactor; tin-free Giese reaction; Introduction Organo halides are among the most useful precursors to
- , equipped with a static mixer having 150 μm width and an automated fraction collector. Using the optimized flow conditions (70 °C, 10–15 min), high yielding conversions of 1b to 3b and 1c to 3c were also obtained. Pictures of the flow microreactor system (MiChS® System X-1), a micromixer (MiChS β-150
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