No abstract

An integrated process including continuous-flow syntheses directly coupled to product isolation via continuous crystallization is presented. For the synthesis part, Ce 0.495 Sn 0.495 Pd 0.01 O 2-δ was used as heterogeneous catalyst in a custom-made packed-bed reactor (the so-called "Plug and Play" reactor) for continuous Suzuki-Miyaura crosscouplings of various para-and ortho-substituted bromoarenes with phenylboronic acid using environmentally friendly aqueous ethanolic mixtures as reaction solvents. The reactions were stable for up to 30 h without any detectable catalyst deactivation. The desired biaryl products were obtained in gram scale with good to excellent yields and high selectivity. For three methyl-, ketyl-, and nitrile-functionalized biphenyl products, isolation was done using water as antisolvent in an integrated crystallization process as continuous downstream protocol. The desired products could be isolated with high purity and with yields of up to 95% for the overall process.

The so‐called plug & play reactor is a novel reaction device with exchangeable reaction segments as well as modules for heating/cooling and mixing. Its performance is demonstrated for two model processes: the production of acetylsalicylic acid with a fixed bed of commercial ion‐exchange particles and a Suzuki‐Miyaura cross‐coupling with a solid Pd‐catalyst developed by us. The reaction progress was monitored by inline UV‐vis spectroscopy and compared with offline HPLC. The novel set‐up leads to quantitative yields and selectivity as well as to an improved practicability of the processes.

Within the “compartmentalised smart factory” approach of the ONE-FLOW project the implementation of different catalysts in “compartments” provided by Pickering emulsions and their application in continuous flow is targeted. We present here the development of heterogeneous Pd catalysts that are ready to be used in combination with biocatalysts for catalytic cascade synthesis of active pharmaceutical ingredients (APIs). In particular, we focus on the application of the catalytic systems for Suzuki–Miyaura cross-coupling reactions, which is the key step in the synthesis of the targeted APIs valsartan and sacubitril. An immobilised enzyme will accomplish the final product formation via hydrolysis. In order to create a large interfacial area for the catalytic reactions and to keep the reagents separated until required, the catalyst particles are used to stabilise Pickering emulsions of oil and water. A set of Ce–Sn–Pd oxides with the molecular formula Ce0.99− xSnxPd0.01O2−δ (x = 0–0.99) has been prepared utilising a simple single-step solution combustion method. The high applicability of the catalysts for different functional groups and their minimal leaching behaviour is demonstrated with various Suzuki–Miyaura cross-coupling reactions in batch as well as in continuous flow employing the so-called “plug & play reactor”. Finally, we demonstrate the use of these particles as the sole emulsifier of oil–water emulsions for a range of oils.

Four tethered titanocene complexes were covalently immobilized onto 3-mercaptopropyl-functionalized silica gel. We have investigated the influence of the length of the tether and of the ansa-bridge on the activity in the heterogeneous hydrosilylation of the cyclic imine 2-phenylpyrroline, taken as an illustrative example. Possible metal leaching during the reaction was investigated using ICP/OES, recycling studies and the three-phase test. The novel immobilized catalysts exhibit an activity similar to their homogeneous analogues in the tested hydrosilylation reactions with a TOF of ~20 h(-1). Furthermore, our results indicate that metal leaching is negligible under the applied reaction conditions.

Here, architectural and scientific researcher Rachel Armstrong questions whether the definition of ‘experimental’ green design presented here goes far enough. She urges architects to not dwell on evaluation processes, performance and ‘strategies’ and to seek a far more radical solution to sustainability, which abandons the current emphasis on industrial technologies and the existing educational and professional frameworks. In its place, she envisions employing biology as a driver for wholly new living materials and systems. Copyright © 2011 John Wiley & Sons, Ltd.