Diverse Supports for Immobilization of Catalysts in Continuous Flow Reactors

Abstract

The rapid development of continuous flow processes is driving innovations in various chemical syntheses and industrial productions. Immobilizing catalysts in flow reactors allows transformations with high-efficiency and excludes the subsequent separation procedures. This concept outlines the approaches to incorporate catalysts within flow reactors, with particular focus on the application of additional supports including inorganic materials like silica, zeolite and reduced graphene oxide, polymeric materials like polymer packings, monoliths, cross-linked gels and polymer brushes, and other materials for specific conditions like transparent glass fibers and glass beads. Furthermore, advanced methods to develop ordered micro-/nanoarrays from internal walls of flow channels for immobilization of catalysts as well as application of innovative vortex fluidic devices are discussed to inspire new designs of supports for novel fluidic reactors with broad applications.

Monolithic Catalysts Supported by Emulsion-Templated Porous Polydivinylbenzene for Continuous Reduction of 4-Nitrophenol

“…A series of porous materials, including metal foams, − carbon materials, − ceramic foams, , porous polymers, − etc., have been successfully employed as support materials. Conventionally, active components were loaded onto porous carriers through solution impregnation, sol–gel process, or covering . However, active components are prone to agglomerate during the loading process and migrate when a chemical reaction is catalyzed, causing a remarkable decline in the catalytic activity. , Polymeric porous carriers, especially microporous organic polymers, exhibit advantages in the design of porous structures and the anchor of active components. , …”

Continuous-Flow PET-RAFT Polymerization in a Packed-Bed Reactor with Porphyrin-Immobilized Silica Particles

“…A flow reactor, with its small radial dimensions and large specific surface area, achieves high light irradiation efficiency within the system . Furthermore, reactions in a flow reactor can be automated and easily scaled up by increasing the number of columns. − Packed-bed reactors have been predominantly reported as the preferred style with heterogeneous catalysts in flow reactors, owing to their high catalyst loading, straightforward preparation, and efficient mixing of the flowing solution . Silica particles, glass beads, and polymer beads , have been applied to such packed-bed reactors with immobilized catalysts.…”

“…30−34 Packed-bed reactors have been predominantly reported as the preferred style with heterogeneous catalysts in flow reactors, owing to their high catalyst loading, straightforward preparation, and efficient mixing of the flowing solution. 35 Silica particles, 36 glass beads, 37 and polymer beads 38,39 have been applied to such packed-bed reactors with immobilized catalysts. Although several reports on photoinduced polymerization in flow reactors have emerged, 40−45 to the best our knowledge, there are few reports characterizing the properties of packed-bed flow reactors for PET-RAFT polymerization.…”