Bromine–Lithium Exchange on a gem-Dibromoalkene, Part 2: Comparative Performance of Flow Micromixers

Abstract

The influence of sixteen passive mixers with eight different angles of 135, 120, 105° (Y mixers), 90° (T mixer), 75, 60, 45 and 30° (W mixers) and two internal diameters (ID = 500 and 250 m) associated with a tubular microflow reactor of ID = 500 m was measured in the stereoselectivity of lithium-bromine exchange on a gem-dibromo alkene, followed by proton trapping. The 45° W-shaped mixer with thinner ID gave the best selectivity for the monobrominated E-product over a range of flow rates without usual cryogenic conditions (20 °C). With methyl benzoylformate as electrophile, the corresponding polyfunctionalized product was obtained with a space time yield of 81 kg/L/h.

Minimizing Material Consumption in Flow Process Research and Development: A Novel Approach Toward Robust and Controlled Mixing of Reactants

“…While the residence time is adjusted by the flow rate, the mixing time can be steered with the rotation speed. Taken together, our multidimensional analysis approach, which goes beyond just the assessment of the mixing performance, which is already well described in the literature, − highlights that the microannular gear pump is a highly powerful tool toward overcoming key hurdles in organic process development.…”

Flow neutralisation of sulfur-containing chemical warfare agents with Oxone: packed bed vs. aqueous solution

“…In this context, the use of miniaturised reactors operated in continuous flow have been shown to be invaluable tools to reach high selectivity sometimes unavailable under classical batch conditions. [13][14][15][16][17][18][19][20] Moreover, such devices offer the possibility to handle and treat large volumes of toxic and corrosive compounds without exposing the operator.…”

“…Due to superior mass transfer and fine residence time control obtained in flow microreactors consecutive competitive reactions can sometimes be avoided with significant enhancement in selectivity. [13][14][15]23,24,[33][34][35][36][37][38][39][40] Thus, we implemented a flow system where a methanolic solution of CEES was introduced at the first inlet and an aqueous solution of Oxone (C = 0.59 mol.L -1 ) at the second inlet, the reactor outlet being quenched with a solution of NaHSO 3 (Fig. 3, Method A).…”

A Synthetic Approach to Dimetalated Arenes Using Flow Microreactors and the Switchable Application to Chemoselective Cross-Coupling Reactions

“…To resolve these shortcomings, we chose to study the generation and reactions of aryllithiums bearing boryl functionalities, Li-B dimetalated arenes, because the transmetalation of the corresponding aryllithium enables the formation of various aryl metal compounds bearing boryl functionalities. The flow microreactor, as a new class of reaction vessels, has attracted considerable attention, , and we have developed microflow synthesis methods that involve very short reaction times using the residence time-control strategy. , The flow microreactor enables the generation and reactions of highly unstable organolithiums bearing electrophilic functionalities, such as alkoxycarbonyl, cyano, nitro, ketone carbonyl, and aldehyde carbonyl groups, before decomposition . Thus, we envisioned that by controlling the residence time it was possible to generate Li-B dimetalated arenes and promote their reaction, particularly with aryllithiums bearing a pinacolborane group (Bpin) as an electrophilic functionality.…”