Improving Solid‐Supported Catalyst Productivity by Using Simplified Packed‐Bed Microreactors

Abstract

Going with the flow: Packed‐bed microreactors are formed from polymeric tubing and a resin‐supported catalyst. By using supported catalysts in flow systems, productivity and recycling are greatly improved. This approach can be used to couple multiple catalysts together for generating complex molecules in one flow‐through process.

Piperazine-Containing Polymer Brush Layer as Supported Base Catalyst in a Glass Microreactor

“…After each experiment, the catalytic microreactor was treated with a 5% solution of triethylamine in acetonitrile and washed with acetonitrile in order to avoid diminished catalytic activity due to possible protonation [10]. The catalytic activity of the piperazine-containing catalytic microreactor remained intact even after 2 months, when stored in a nitrogen box.…”

“…Basic organocatalysts such as 1,5,7-triazabicyclo[4.4.0]undec-3-ene (TBD) [10], 4-dimethylaminopyridine (DMAP) [10], and piperazine [11] have been tethered to a solid support and implemented in microfluidic devices through the packed-bed approach. Although this approach has advantages such as high catalyst loading, a wide range of catalytic supports, and easy fabrication of the catalytic device by filling the channels with functional catalytic particles, however, uncontrolled fluid dynamics, heat transfer limitations, and pressure drop developing along the microchannel are serious limitations.…”

Polymer‐Supported Organosuperbases

“…For example, a variety of primary/secondary/aliphatic/aromatic amines and aliphatic/aromatic thiols could smoothly react with activated olefins in the presence of 10 mol% of a nitrate salt of PS-PAPT or PS-N3PAPT [34] (Scheme 6.10). Polymer-or mesoporous silica-supported TBD reagents have also been shown to catalyse efficiently Knoevenagel condensations and, in some cases, be feasible for continuous-flow synthesis in a microreactor [36,37,43,44].…”

Gallium-containing polymer brush film as efficient supported Lewis acid catalyst in a glass microreactor

“…a) with a packed-bed microreactor, where the catalyst is attached to a polymeric material enclosed in the microchannel [5], and b) when the catalyst is covalently connected to the inner walls of a glass microreactor [6]. Although the former approach has advantages such as high catalyst loading and easy fabrication of the catalytic device by filling the channels with functional catalytic particles, however, heat transfer limitations and pressure drop developing along the microchannel are serious drawbacks [7].…”