Transformações de substratos biorrenováveis catalisadas por heteropoliácidos

Detalhes bibliográficos
Ano de defesa: 2020
Autor(a) principal: Rafaela Ferreira Cotta Maciel
Orientador(a): Não Informado pela instituição
Banca de defesa: Não Informado pela instituição
Tipo de documento: Tese
Tipo de acesso: Acesso aberto
Idioma: por
Instituição de defesa: Universidade Federal de Minas Gerais
Brasil
ICX - DEPARTAMENTO DE QUÍMICA
Programa de Pós-Graduação em Química
UFMG
Programa de Pós-Graduação: Não Informado pela instituição
Departamento: Não Informado pela instituição
País: Não Informado pela instituição
Palavras-chave em Português:
Link de acesso: http://hdl.handle.net/1843/35886
Resumo: In this work, several catalytic processes for the valorization of a series of natural monoterpenic compounds were developed, including limonene, a low cost and abundant substrate widely available in Brazil. All processes are in line with green chemistry concepts, with the use of renewable starting materials, green solvents, mild reaction conditions and in the presence of heterogeneous, non-toxic and non-corrosive catalysts. Coupling reactions between monoterpene compounds (limonene, α-terpineol, α-pinene, β-pinene, nerol or linalool) and aldehydes or epoxides (cuminaldehyde, trans-cinnamaldehyde, benzaldehyde, crotonaldehyde, phenylacetaldehyde or styrene oxide) were performed to obtain different oxygen-containing bicyclic and tetracyclic products in high yields. In these reactions, Cs2.5H0.5PW12O40 (CsPW) and silica-supported H3PW12O40 (HPW/SiO2) were used as acidic heterogeneous catalysts in green solvents, i.e., diethylcarbonate (DEC), dimethylcarbonate (DMC), anisole and biomass derived 2-methyltetrahydrofuran (MeTHF). The isomerization of limonene oxide using (HPW/SiO2) as heterogeneous catalyst was also studied to give dihydrocarvone and carvenone with 90% and 93% yields, respectively. The solvents that presented the best results were the ecologically friendly DEC and DMC. Finally, the stereoselective isomerization of cis-limonene oxide to give trans-dihydrocarvone in DMC solutions was also developed.