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

Abstract

The covalent attachment of piperazine onto the inner walls of a microreactor using glycidyl methacrylate polymer brushes has been demonstrated. The piperazine-containing polymer brushes were first grown on a flat silicon oxide surface and were characterized by contact angle, Fourier transform infrared (FT-IR), ellipsometry, and X-ray photoelectron spectroscopy (XPS). The applicability of the catalytic polymer brushes in a microreactor was demonstrated for the Knoevenagel and nitroaldol condensation reactions, and the synthesis of coumarin derivatives. The catalytic activity of the microreactor was still intact even after 2 months.

Single-Molecule Observations Provide Mechanistic Insights into Bimolecular Knoevenagel Amino Catalysis

“…The formation of the product follows approximately an exponential saturation behavior very consistent with the proposed model of the iminium pathway (equation derivation in the Supporting Information). The kinetics of product formation with exponential saturation behavior was previously observed in the Knoevenagel reaction of benzaldehyde with malononitrile catalyzed by piperazine bound to polymer brush layer in a glass microreactor …”

“…The kinetics of product formation with exponential saturation behavior was previously observed in the Knoevenagel reaction of benzaldehyde with malononitrile catalyzed by piperazine bound to polymer brush layer in a glass microreactor. 49 A comparison of the SM results with macroscopic rate constants even in the same solvent is not straightforward because of the different experimental conditions used (surface catalysis in SM vs solution catalysis in bulk).…”

A versatile optofluidic microreactor for artificial photosynthesis induced coenzyme regeneration and l-glutamate synthesis

“…For immobilizing catalysts on the wall of the microreactors, several researchers proposed different methods. [36][37][38][39] However, a simple, efficient, evaporation-proof, easy to scale up, and environment-friendly method is required. To meet these requirements, in this paper, we described a novel method to fabricate glass capillary-based optofluidic microreactors.…”

Wirtschaft

“…The catalytic device stored in a nitrogen box for 30 days and reused for the same reaction discussed above, showed similar activity, demonstrating its long‐term stability. Piperazine‐supported PGMA brushes tethered onto the inner walls of a microreactor were used to study Knoevenagel and nitroaldol condensation reactions, and the synthesis of coumarins 96. Conversions up to 96% were obtained and the catalytic activity was maintained even after 2 months.…”