Catalysis in flow microreactors with wall coatings of acidic polymer brushes and dendrimer-encapsulated nanoparticles

Continuous-flow microreactors are an invaluable tool to carry out organic reactions owing to their numerous advantages with respect to batch scale synthesis. In particular, supported catalysts enable heterogeneous catalysis to be conducted in an efficient way. In this thesis, the development and activity of different organic and nanometallic catalysts supported in different ways on the inner walls of glass microreactors, has been presented Their catalytic activity is proven in a variety of acid- catalyzed reactions, C-C cross-couplings, and reductions. Chapter 2 presents a literature overview about the state-of-the-art of nanoparticle catalysis in microfluidic reactors. The first part of the thesis shows two strategies for the introduction of sulfonic acid groups within microreactors and their activity in several acid-catalyzed reactions. The second part of this thesis deals with the use of dendrimer-encapsulated metallic nanoparticles (M DENs) covalently attached to the inner surface of the microreactors. Pd DENs catalyzed efficiently C-C cross- couplings, such as Suzuki-Miyaura and Sonogashira reactions. Bimetallic Au/Ag DENs were employed in the reduction of 4-nitrophenol. In summary, the results presented in this thesis highlight the advantages of using supported catalysts within continuous-flow microreactors for heterogeneous catalysis. Functionalization of the large inner surface of microreactors was achieved by using a single layer of an organic acid catalyst, by catalyst-bearing polymer brushes and by dendrimer-encapsulated nanoparticles. The vast portfolio of supported catalysts together with the safety and the efficiency of carrying out many organic reactions will undoubtedly establish microfluidic reactors as a core technology in chemical synthesis and analysis.