Catalysis in Flow: Why Leaching Matters

Abstract

The ability to deploy heterogeneous catalysts in continuous flow depends on their stability against deactivation and for reactions in the liquid phase (leaching). This article will discuss the current understanding how leaching can affect catalyst activity and deactivation. Future prospects for the development of the field are proposed.

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

“…The role of leached Pd ions in this case seems minimal, as well as for the results reported by Stouten et al [82,83]. Finally, an overview of the importance of the leaching problem in flow chemistry has been very recently proposed by Hii et al [84].…”

Long-Term Continuous Co-reduction of 1,1,1-Trichloroethane and Trichloroethene over Palladium Nanoparticles Spontaneously Deposited on H2-Transfer Membranes

“…Catalyst leaching commonly occurs in continuously operated systems, and it is a detrimental factor that induces significant loss of catalytic activity . During the 90 days of continuous operation, weekly monitoring of total Pd concentrations in the effluent samples revealed that Pd 0 detached from the membrane surface was consistently minimal (6.2 ± 4.4 μg/L).…”

Effects of Cl on the reduction of supported PdO in ethanol/water solvent mixtures

“…In recent years, there has been particular interest in translating the myriad of Pd-catalysed reactions into continuous flow processes, which will require the use of a heterogeneous or immobilised form of the catalyst. In these cases, leaching of Pd into the mobile phase, either as molecular species or as colloids, is a significant problem [6][7][8][9], as it directly affects catalyst longevity, recovery, and purification of the product, which have thus far restricted wider application of supported Pd catalysts within the pharmaceutical industry.…”