Desenvolvimento de catalisadores para aplicação em reações de formação de ligações C-C estereosseletivas

• Ano de defesa: 2017
• Autor(a) principal: Rocha, Mariane [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo
• Palavras-chave em Português: Organocatalysis; Aldol reaction; Asymetric synthesis; Ordered mesoporous Silicas; SBA-15; Organocatálise; Reação aldólica; Síntese assimétrica; Sílicas mesoporosas ordenadas
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=5059460; http://repositorio.unifesp.br/handle/11600/49919

In this work the immobilization of organocatalysts in ordered mesoporous silicas, type SBA-15, was studied in order to obtain a heterogeneous system and to facilitate the recycling of the organocatalyst and also to improve its catalytic efficiency. In this context, organocatalysts derived from L-proline were synthesized and incorporated into the SBA-15 by adsorption and chemically linked by functionalization with organosilane. The catalytic systems obtained were characterized and used as catalysts in asymmetric aldol reactions, using cyclohexanone and p-nitrobenzaldehyde as reagents. The organocatalysts were also incorporated into SBA-15 by in situ adsorption, with the catalytic reaction reagents themselves. The incorporation of the organocatalytic agents did not cause any structural damage to the SBA-15, maintaining its mesoporous structure. However, there was a reduction of the surface area and pore volume indicating the insertion of organic species in the mesopores of the SBA-15. Since the incorporation was higher when the adsorption method was used, in addition, the in situ process adsorption resulted in a larger amount of material within the mesopores. The results of the catalytic tests showed that the organocatalysts incorporated to SBA-15 by in situ adsorption were more efficient, as they resulted in greater conversion and reactivity selectivity.