Controlled multifunctionalization of magnetic nanoparticles for applications in catalysis
- Autores: Carmen Andrada Mak
- Directores de la Tesis: Miquel Angel Pericàs (dir. tes.), Teresa Pellegrino (codir. tes.)
- Lectura: En la Universitat Rovira i Virgili ( España ) en 2017
- Idioma: español
- Tribunal Calificador de la Tesis: Oliver Reiser (presid.), Alexandr Shafir (secret.), Renata Riva (voc.)
- Programa de doctorado: Programa de Doctorado en Ciencia y Tecnología Química por la Universidad Rovira i Virgili
- Materias:
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- Resumen
The present thesis is focused on the development of new hybrid magnetic nanomaterials for applications in catalysis.
In the first part, a general introduction regarding the concept of catalysis and its use in modern industry is described. Even more, the importance of the use of materials in catalysis and nanotechnology is also presented.
In the second part, a detailed description of the use of such materials for certain catalytic transformations is described.
The first project in the second part involves the development of two hybrid magnetic materials comprising κ-carrageenan and Fe3O4 magnetic nanoparticles that are tested as catalysts for the Michael addition of aldehydes to nitroalkenes. Surprisingly, one of the materials, prepared from unmodified κ-carrageenan, presented catalytic activity in the reaction of choice, while the individual components were inactive. This proves there is a synergistic effect between the magnetic nanoparticles and κ-carrageenan. The second catalytic material, bearing a diphenylprolinol silyl ether moiety, was also very efficient for this transformation, leading to the corresponding adducts in excellent enantioselectivitiess. After the reaction is complete, the catalysts can be easily recovered by simple magnetic decantation.
The second project of this part implies the design of different multifunctional materials containing 5-(4-carboxyphenyl)-5,10,15-tris(4-phenoxyphenyl)-porphyrin and iron oxide magnetic nanoparticles (MNPs). Moreover, a new type of polymeric material comprising the same porphyrin and a polysaccharide, k-carrageenan, was also developed. All synthesized materials were tested as catalysts for the Knoevenagel condensation of aldehydes at room temperature. In all cases the desired products were obtained in short reaction times and with high yields. The best performing porphyrin–based catalyst, containing magnetic nanoparticles and a silica linker, was also tested as optical sensor for CO2 detection. Even more, the novel designed catalytic systems meets the sustainable chemistry requirements, since they can be recovered and reused several times.
The third project of the second chapter is divided in two parts. The first one describes the synthesis and characterization of new hybrid magnetic materials and their application in the aldol condensation. Two such materials containing chitosan and iron oxide magnetic nanoparticles were designed and tested for the above-mentioned reaction, giving rise to the desired adducts in good yields and high enantioselectivities. The second part of this project is related to the design of a multicatalytic system, by combining a metal and an organocatalyst on the same support, iron oxide magnetic nanoparticles. Such a system presents the advantage of easy recovery of the catalysts, by simple magnetic decantation, improving thus its reusability.
The last part presents the overall conclusions of the present thesis.
