Oxidação de álcoois terpênicos por oxigênio molecular catalisada por Pd(OAc)2 na presença de bases nitrogenadas e carbonatos

• Autor(a) principal: Carari, Danieli Marcolan
• Data de Publicação: 2011
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2103
• topic: Alcoóis terpênicos; Catalisadores; Carbonatos; Terpenic alcohols; Catalysts; Carbonates; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA INORGANICA

The main objective herein was evaluate the catalytic performance of Pd(OAc)2 in toluene solutions, containing nitrogen and anionic bases, which may act as ligands as well as exogenous base, in oxidation reactions of terpenic alcohols by molecular oxygen. In this system, terpenic alcohols were selectively oxidated in homogeneous phase where the oxidant is of minimal environmental impact. The effects of the nature of different nitrogen ligands and anionic bases in the activity and selectivity of the catalyst were investigated. In particular, it was found that the system Pd(OAc 2/pyridine/K2CO3/ toluene/O2 was the most effective in promoting oxidation of substrates studied, β-citronellol and geraniol, with high conversion and selectivity to aldehydes upper to 90%. This system was more effective than those systems described in literature, and also evaluated here, such as Pd(OAc)2/pyridine/MS3A/toluene/O2. It also conducted a kinetic study of citronellol oxidation catalyzed by Pd(OAc)2/pyridine/K2CO3 where the activation energy of the process was determined. On the other hand, heterogeneous reactions were performed through the process of impregnation the Pd(OAc)2/pyridine catalyst on K2CO3 solid support. The synthesis process proved simple and efficient. However, although the catalyst Pd(OAc)2/pyridine supported in K2CO3 has been shown be active and selective in converting the terpenic alcohols to aldehydes, stability and deactivation problems occur and it is not reusable.