3D-printed devices for continuous-flow organic chemistry

• Vincenza Dragone,
• Victor Sans,
• Mali H. Rosnes,
• Philip J. Kitson and
• Leroy Cronin

Beilstein J. Org. Chem. 2013, 9, 951–959, doi:10.3762/bjoc.9.109

• simplicity of designing and building flow reactors employing 3D-printing techniques allows for an easy and convenient integration of devices in a flow setup. Therefore it represents a very attractive way to design and build new continuous-flow rigs for organic synthesis. Results and Discussion Experimental

• setup The 3D-printed flow reactors used to carry out the organic syntheses were designed by using a 3D CAD software package (Autodesk123D®), which is freely distributed and produces files that can be converted to the correct format read by the 3DTouchTM printer. This 3D printer heats a thermopolymer

• reliability of the 3D-printed devices as flow reactors, we decided to connect one reactor to the other and perform a two steps flow reaction in an automated way. To this end, we employed two R2 reactionware devices connected in series (Figure 7), to monitor the formation of the final product using the in-line

Flow photochemistry: Old light through new windows

• Jonathan P. Knowles,
• Luke D. Elliott and
• Kevin I. Booker-Milburn

Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229

• -utilised technique in general organic synthesis. Recent developments in flow photochemistry have the potential to allow this technique to be applied in a more mainstream setting. This review highlights the use of flow reactors in organic photochemistry, allowing a comparison of the various reactor types to

Continuous-flow enantioselective α-aminoxylation of aldehydes catalyzed by a polystyrene-immobilized hydroxyproline

• Xacobe C. Cambeiro,
• Rafael Martín-Rapún,
• Pedro O. Miranda,
• Sonia Sayalero,
• Esther Alza,
• Patricia Llanes and
• Miquel A. Pericàs

Beilstein J. Org. Chem. 2011, 7, 1486–1493, doi:10.3762/bjoc.7.172

• alternative for improving the productivity of catalytic species results from the implementation of heterogenized catalysts in continuous-flow reactors. Flow chemistry has experienced a very important development in the last ten years as an emerging technology for organic synthesis [51][52][53][54][55][56][57

Multistep flow synthesis of vinyl azides and their use in the copper-catalyzed Huisgen-type cycloaddition under inductive-heating conditions

• Lukas Kupracz,
• Jan Hartwig,
• Jens Wegner,
• Sascha Ceylan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2011, 7, 1441–1448, doi:10.3762/bjoc.7.168

• , entry 8). Finally, both flow reactors were telescoped, which allowed us to prepare vinyl azides 4a–e and 4g–i in one flow process starting from alkenes 2a–e and 2g–i (Scheme 3). Advantageously, isolation and purification of intermediate iodo azides 3 was avoided. As a consequence we achieved improved

• flow conditions. Regeneration of functionalized polymers 5 and 8. Preparation of triazoles 12a–l by using inductively heated copper turnings as a packed-bed material inside flow reactors. Azido iodination of alkenes 2a–f under flow conditions with polymer-bound bisazido iodate(I) complex 5

Continuous preparation of carbon-nanotube-supported platinum catalysts in a flow reactor directly heated by electric current

• Alicja Schlange,
• Antonio Rodolfo dos Santos,
• Ulrich Kunz and
• Thomas Turek

Beilstein J. Org. Chem. 2011, 7, 1412–1420, doi:10.3762/bjoc.7.165

• preparation in a flow reactor which could be used at a large scale. Keywords: carbon nanotubes; continuous catalyst synthesis; direct electrical heating; flow reactors; fuel cell platinum catalyst; Introduction Batch processes represent the state of the art in catalyst preparation. One reason for employing

Translation of microwave methodology to continuous flow for the efficient synthesis of diaryl ethers via a base-mediated S_NAr reaction

• Charlotte Wiles and
• Paul Watts

Beilstein J. Org. Chem. 2011, 7, 1360–1371, doi:10.3762/bjoc.7.160

• -temperature flow reactors, which can be scaled to increase production volume without changing the reaction conditions employed [23][24][25], resulting in a reduction in energy usage per mole. With this in mind, we report herein the translation, and further development, of a microwave method for the SNAr

Continuous flow hydrogenation using polysilane-supported palladium/alumina hybrid catalysts

• Hidekazu Oyamada,
• Takeshi Naito and
• Shū Kobayashi

Beilstein J. Org. Chem. 2011, 7, 735–739, doi:10.3762/bjoc.7.83

• swell in any solvent, and were predicted to be applicable to continuous flow reactors. In this study, we investigated hydrogenation reactions of C–C double and triple bonds as well as various other functional groups using continuous flow systems with Pd/(PSi–Al2O3) catalysts. A schematic diagram of the

Unusual behavior in the reactivity of 5-substituted-1H-tetrazoles in a resistively heated microreactor

• Bernhard Gutmann,
• Toma N. Glasnov,
• Tahseen Razzaq,
• Walter Goessler,
• Dominique M. Roberge and
• C. Oliver Kappe

Beilstein J. Org. Chem. 2011, 7, 503–517, doi:10.3762/bjoc.7.59

• tetrazoles in flow reactors utilizing direct electrical resistance heating would be the occurrence of extreme hot spots or uneven temperature distributions along the capillary. To explain the observed degradation rates, however, average temperatures well above 300 °C in the resistively heated reactor have to

• . Only renewed loading of the coil by running a Mizoroki–Heck reaction with Pd(OAc)2 or by simply processing a Pd(OAc)2 solution through the coil at elevated temperature regenerated the “palladated” stainless steel coils. Influence of pressure on reaction rate in flow reactors In the resistively heated

• examples have been reported in the literature, but the number of cases where a pressure influence is seen in the medium pressure range (50–200 bar) accessible in standard flow reactors is rather limited [69][70]. One transformation where pressure-dependent rate enhancements (1–600 bar) have been observed

Stereoselectivity of supported alkene metathesis catalysts: a goal and a tool to characterize active sites

• Christophe Copéret

Beilstein J. Org. Chem. 2011, 7, 13–21, doi:10.3762/bjoc.7.3

• supported catalysts Metathesis of propene in flow reactors can easily allow the kinetic stereoselectivity of a catalyst at low contact times (high space velocity) to be obtained. For instance, [(≡SiO)(t-BuCH2)Re(=CHt-Bu)(≡Ct-Bu)] displays a (E/Z)0 of 2, which is very close the thermodynamic equilibrium

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

• reaction is not only a suitable model but also one of industrial importance since this is the main production process for formic acid. Keywords: direct electric heating; flow reactors; micro reactors; organic chemistry; reaction kinetics; Introduction Continuously operated small reactors for organic

• waves is limited. Shielding of the heating chamber is required to prevent electromagnetic waves entering the environment. In this paper we provide an example of a much simpler method to heat small flow reactors. From our point of view the easiest way to transfer heat is to heat the reactor wall directly

• microwave ovens and this method as well as the application in organic flow synthesis. Experimental setup for heating tubular flow reactors by passing electric current directly through the reactor wall. The characteristic linear temperature profile along the reactor length is also given. Conversion as a

From discovery to production: Scale- out of continuous flow meso reactors

• Peter Styring and
• Ana I. R. Parracho

Beilstein J. Org. Chem. 2009, 5, No. 29, doi:10.3762/bjoc.5.29

• Suzuki and Heck coupling reactions at elevated temperatures while the nickel catalyst is active in the Kumada coupling [11][12] reaction at room temperature in batch (Scheme 1) and continuous flow reactors. In the latter, the catalyst is packed into a 3 mm diameter glass reactor tube of length 25 mm and

• than the yields originally reported for single channel meso flow reactors. It is proposed that during the first hours of the reaction there is period of induction that conditions the reactor and activates the catalyst. Steady state is then achieved after this induction period, which occurs irrespective

• ) based on 4-bromoanisole. However, the TOF was significantly reduced from the reaction carried out at half the flow rate (1.5 h−1). It should be noted that the TOFs in flow reactors are lower than in batch as we are dealing with small flows through a packed bed reactor and hence the catalyst

The development and evaluation of a continuous flow process for the lipase- mediated oxidation of alkenes

• Charlotte Wiles,
• Marcus J. Hammond and
• Paul Watts

Beilstein J. Org. Chem. 2009, 5, No. 27, doi:10.3762/bjoc.5.27

• reactors, have been shown to offer many advantages to the synthetic chemist, such as reduced reactions times, increased catalytic efficiency, increased product purity and atom efficiency [23][24][25][26]. More recently, authors have begun to incorporate biocatalysts into flow reactors as a means of

• biocatalyst with respect to peracid formation, facilitating a series of oxidations including alkenes [21] and ketones via the Baeyer–Villiger reaction [22] and retaining the broad substrate specificity of Candida antarctica lipase B. In the past decade micro reactors, and more generically continuous flow

Polyionic polymers – heterogeneous media for metal nanoparticles as catalyst in Suzuki–Miyaura and Heck–Mizoroki reactions under flow conditions

• Klaas Mennecke and
• Andreas Kirschning

Beilstein J. Org. Chem. 2009, 5, No. 21, doi:10.3762/bjoc.5.21

• transition metals on solid phases inside monolithic flow reactors [9][10][11][12][13][14][15][16][17][18] we describe the preparation of palladium nanoparticles loaded on polyionic polymers and their use under continuous flow conditions in various C-C-cross-coupling reactions [19][20][21][22]. Results and

• ) under flow conditions. Deviations may result from work up as only isolated yields are presented. Repeated Heck–Mizoroki reaction of 4′-iodoacetophenone (23) with styrene (29) under flow conditions. Preparation of Pd(0) nanoparticles inside flow reactors. Suzuki–Miyaura reactions catalyzed by Pd

• nanoparticles 3 inside flow reactors. Heck–Mizoroki reactions catalyzed by Pd nanoparticles 3 inside flow reactors. Supporting Information Supporting Information File 48: Experimental Acknowledgments This work was supported by the Fonds der Chemischen Industrie and the Deutsche Forschungsgemeinschaft (grant

Chemistry in flow systems

• Andreas Kirschning

Beilstein J. Org. Chem. 2009, 5, No. 15, doi:10.3762/bjoc.5.15

• techniques that originate from high-throughput chemistry laboratories as they can be combined with the use of immobilized reagents or catalysts, or by using fixed bed reactors in parallel. These developments in flow techniques using mini and micro flow reactors have initiated changes that will pave the way