Experimental strategies for increasing the catalyst turnover number in a continuous Heck coupling reaction

Organic solvent resistant poly(ether-ether-ketone) nanofiltration membranes

“…In our previous work we already proved the excellent stability and performance of native PEEK nanofiltration membranes prepared in our laboratory [26,27]. We used a PEEK nanofiltration membrane (MWCO $ 395 g mol À 1 ) in a continuous catalytic reaction/separation (Heck reaction) for 300 h. The membrane was resistant to high temperature (80 1C) and high concentration of base (40.9 mol L À 1 triethylamine) in DMF.…”

“…We used a PEEK nanofiltration membrane (MWCO $ 395 g mol À 1 ) in a continuous catalytic reaction/separation (Heck reaction) for 300 h. The membrane was resistant to high temperature (80 1C) and high concentration of base (40.9 mol L À 1 triethylamine) in DMF. In addition, the retention of catalyst was around 75% throughout the experiment [27]. Since the aim of the work was to demonstrate successful application no details on the membrane production and characterisation were presented.…”

Tools for chemical synthesis in microsystems

“…46 One newer approach to recycling of catalysts is the use of organic solvent nanofiltration (OSN) membranes that separate larger molecules (∼200-1000 Da), such as complex catalysts, from smaller starting materials and products. 47 These membranes are typically made from polyamide, polyimide, or PDMS materials and have been demonstrated in homogeneous catalyst recycling experiments in batch and flow. 47,48 Ongoing efforts aim to improve the base stability of OSN membranes to enable applications in cross-coupling reactions.…”

Continuous Consecutive Reactions with Inter‐Reaction Solvent Exchange by Membrane Separation

“…The first reaction, a palladium‐catalyzed Heck coupling, was performed in a continuous unit consisting of a plug flow reactor and completely stirred membrane reactor/separator in series (PFR‐ m ‐CSTR; Figure ). Although the conversion in the PFR reactor is relatively low, our previous studies have shown that successful pre‐activation of the catalyst occurs within the PFR . Preliminary kinetic experiments were performed to determine the effect of catalyst loading on the reaction rate and estimate the minimum residence time (RT) achievable in the reactor.…”