Uso do glicerol, glicerol bruto da produção do biodiesel e outros solventes próticos na síntese de cetonas (E)-α,β-insaturadas
Data
2018-03-29
Autores
Torrezan, Guilherme Silva
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O glicerol é o principal co-produto da produção de biodiesel e vem sendo considerado como um solvente verde. Neste trabalho, utilizamos o glicerol e o glicerol bruto proveniente da produção de biodiesel para a síntese das cetonas α,β-insaturadas (2E, 4E) -1,5-difenilpenta-2,4-dien-1-ona (1) e (2E, 6E) -2,6-dibenzilidenociclohexanona (2), utilizando reações aldólicas mono- e dicondensadas, respectivamente. As cetonas 1 e 2 sintetizadas em glicerol e glicerol bruto forneceram rendimentos superiores aos outros solventes próticos, incluindo etanol, metanol, PEG-400 e água. Para investigar as razões que justificariam a eficiência do glicerol, foram realizados os cálculos computacionais usando a teoria do funcional da densidade, que validou o mecanismo E1cB, assim como uma barreira de energia de ativação que favorece a rota sintética usando o glicerol. Além disso, o glicerol bruto de óleo de milho e girassol foram utilizados na síntese de 1 e 2 durante quatro reciclos, demonstrando rendimentos finais de 59,0 e 48,2%, respectivamente.
Glycerol is main co-product from biodiesel production and has been recognized as green solvent. Herein, we used glycerol and crude glycerol for synthesis of α,β-unsaturated ketones: (2E,4E)-1,5-diphenylpenta-2,4-dien-1-one (1) and (2E,6E)-2,6 dibenzylidenecyclohexanone (2), using mono- and dicondensation aldol reactions, respectively. Glycerol and crude glycerol were able to furnish 1 and 2 in yields higher than other protic solvents, including ethanol, methanol, PEG-400 and water. In order to investigate reasons for efficiency glycerol, we performed computational calculations using Density Functional Theory, which has validated E1cB mechanism, as well as favorable enegy barrier using glycerol. In addition, crude glycerol from corn and sunflower oils were used in synthesis of 1 and 2 for four recycles, displaying final yields of 59.0 and 48.2%, respectively.
Glycerol is main co-product from biodiesel production and has been recognized as green solvent. Herein, we used glycerol and crude glycerol for synthesis of α,β-unsaturated ketones: (2E,4E)-1,5-diphenylpenta-2,4-dien-1-one (1) and (2E,6E)-2,6 dibenzylidenecyclohexanone (2), using mono- and dicondensation aldol reactions, respectively. Glycerol and crude glycerol were able to furnish 1 and 2 in yields higher than other protic solvents, including ethanol, methanol, PEG-400 and water. In order to investigate reasons for efficiency glycerol, we performed computational calculations using Density Functional Theory, which has validated E1cB mechanism, as well as favorable enegy barrier using glycerol. In addition, crude glycerol from corn and sunflower oils were used in synthesis of 1 and 2 for four recycles, displaying final yields of 59.0 and 48.2%, respectively.
Descrição
Palavras-chave
Glicerol, Solventes próticos, Cetonas, Condensação aldólica, Biodiesel, Química verde, Glycerol, Protic solvents, Ketones, Aldol condensation, Green chemistry