The Continuous-Flow Synthesis of Styrenes Using Ethylene in a Palladium-Catalysed Heck Cross-Coupling Reaction

Abstract

We report a palladium-catalysed ethylene Heck reaction for the vinylation of aryl iodides using a tube-in-tube gas-liquid reactor. The flow process afforded various styrenes in short reaction times, employing moderate ethylene pressure.

Chemical reaction engineering, process design and scale-up issues at the frontier of synthesis: Flow chemistry

“…The latter sensibly improved selectivity at quantitative conversion [36]. Styrenes were also synthesized in flow by the same group from different aryl iodides and ethylene [37], as well as unsymmetrical stylbenes [38]. A tube-in-tube reactor configuration was proposed, allowing gas permeation from the shell to the inner pipe, where the liquid reactants are 6 flowing.…”

Continuous-flow Heck coupling reactions catalyzed by Pd complexes of amidoxime fibers

“…The continuous-flow technique was combined with the reactive gas as a means of merging the gas build-up into the molecule, and the resulting styrene reacted with the iodoaryl substrate at 120 °C for 20 min to give about 70% of the stilbene product. 13 Viviano et al 14 have investigated the conditions for the palladium acetate catalyzed reaction of 4-iodophenyl ether with methyl vinyl ketone under intermittent microwave treatment and continuous flow, and the product yield was 67% in the flow state with a residence time of 10 min at 180 °C, while the flow technique optimized the reaction conditions to give high product yields and selectivity in very short reaction times. Laudadio et al 15 investigated the Heck coupling reaction catalyzed by several Pd catalysts in a continuous-flow-filled bed, and the experimental results showed that the Pd(PPh 3 ) 4 -PS catalyst gave 93% regioselectivity, an 81% separation yield, and less than 1% leaching of Pd after one reaction, and could be washed and dried for reuse.…”

Supported Liquid Phase Catalyst coating in micro flow Mizoroki–Heck reaction

“…Recently however, the true potential of these systems was recognized. Novel Process Windows, as proposed by Hessel [14], aim to exploit the use of harsh process conditions in unconventional processes, boosting chemical productivity by orders of magnitude [15][16][17][18][19][20][21][22][23][24][25][26]. In micro flow, the improved process control and limited volume mean a higher degree of safety, allowing the application of processes or process conditions that would otherwise be discarded [27][28][29][30][31][32][33].…”