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

• -bed microreactor was found to possess good long-term stability and could be used for the catalysis of a range of aldol reactions, one example is given in Scheme 8. Conveniently, just one starting material stock solution was all that was necessary, meaning that 4-chlorobenzaldehyde (64) could be

• effect highly selective aldol reactions of simple ketones and aromatic aldehydes in flow [106]. Photoinduced thiol–ene coupling was used to tether the catalyst onto silica particles, yielding an easily handled powder which was packed into a short stainless steel column (Scheme 8). The resultant packed

Continuous flow nitration in miniaturized devices

• Amol A. Kulkarni

Beilstein J. Org. Chem. 2014, 10, 405–424, doi:10.3762/bjoc.10.38

• , can improve the selectivity of p-nitrotoluene in a conventional reactor using a mixed acid as the nitrating agent [52][53]. Continuous flow nitration of toluene in a packed bed microreactor using concentrated nitric acid as the nitrating agent was reported by Halder et al. [54]. Different ‘solid acid

Flow synthesis of phenylserine using threonine aldolase immobilized on Eupergit support

• Jagdish D. Tibhe,
• Hui Fu,
• Timothy Noël,
• Qi Wang,
• Jan Meuldijk and
• Volker Hessel

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

• 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

• becomes more substantial. Therefore, we chose 70 °C as the optimum temperature for the following experiments. Effect of flow rates When operating the packed bed microreactor with immobilized TA at 70 °C, the yield of phenylserine can be further increased to 30% at longer residence times (Figure 6). This

Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor

• Rajesh Munirathinam,
• Roberto Ricciardi,
• Richard J. M. Egberink,
• Jurriaan Huskens,
• Michael Holtkamp,
• Herbert Wormeester,
• Uwe Karst and
• Willem Verboom

Beilstein J. Org. Chem. 2013, 9, 1698–1704, doi:10.3762/bjoc.9.194

• . a) with a packed-bed microreactor, where the catalyst is attached to a polymeric material enclosed in the microchannel [5], and b) when the catalyst is covalently connected to the inner walls of a glass microreactor [6]. Although the former approach has advantages such as high catalyst loading and

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

• . Keywords: aminoxylation; flow chemistry; heterogeneous catalysis; packed-bed microreactor; proline/thiourea catalysis; Introduction Continuous flow chemistry [1][2][3], performed in small dimension tubing or channels, differs from batch chemistry in that mixing and heat transfer are significantly faster

Coupled chemo(enzymatic) reactions in continuous flow

• Ruslan Yuryev,
• Simon Strompen and
• Andreas Liese

Beilstein J. Org. Chem. 2011, 7, 1449–1467, doi:10.3762/bjoc.7.169

• ). The coupled reaction is carried out in a continuously operated packed-bed microreactor. As compared to the batch-mode experiments, higher concentrations of H2O2 were applied without detectable catalyst deactivation after 24 hours. At 100% conversion, a space-time yield of 646 g L−1 day−1 was obtained

A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed- bed microreactor

• Andrew Bogdan and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2009, 5, No. 17, doi:10.3762/bjoc.5.17

• characterization of a simplified packed-bed microreactor using an immobilized TEMPO catalyst shown to oxidize primary and secondary alcohols via the biphasic Anelli-Montanari protocol. Oxidations occurred in high yields with great stability over time. We observed that plugs of aqueous oxidant and organic alcohol

• potential as continuous flow processes. Realizing this, we developed a catalytic packed-bed microreactor that could be used for the continuous flow oxidation of alcohols to aldehydes or ketones. Oxidations that do not require transition metal catalysts are particularly appealing since there is neither

• , increasing the safety of large-scale oxidations. Furthermore, it was determined that the use of a packed-bed microreactor facilitates efficient mixing of a biphasic system without destroying the solid support, a common problem with stirred systems [4]. Results and Discussion Previously we reported that