Por favor, use este identificador para citar o enlazar este ítem:
https://repositorio.ufba.br/handle/ri/14348
metadata.dc.type: | Artigo de Periódico |
Título : | Transesterification of rapeseed oil with ethanol: I. catalysis with homogeneous Keggin heteropolyacids |
Otros títulos : | Applied Catalysis A: General |
Autor : | Morin, P. Hamad, B. Sapaly, G. Rocha, M. G. Carneiro Oliveira, P. G. Pries de Gonzalez, W. A. Sales, E. Andrade Essayem, Nadine |
metadata.dc.creator: | Morin, P. Hamad, B. Sapaly, G. Rocha, M. G. Carneiro Oliveira, P. G. Pries de Gonzalez, W. A. Sales, E. Andrade Essayem, Nadine |
Resumen : | Heteropolyacids (HPA) with Keggin structure were evaluated as homogeneous Br∅nsted acid catalysts in the reaction of rapeseed oil transesterification with methanol and ethanol at 358 K and atmospheric pressure. Rapeseed oil transesterification with ethanol over anhydrous Keggin HPAs leads to higher conversion level than H2SO4 compared at equivalent H+ concentration and H2O/H+ molar ratio. By contrast, Phosphoric acid, a quite weaker mineral acid, structurally close to H3PW12O40, is not operative under similar conditions. This demonstrates the advantages of strong Br∅nsted acids in vegetable oil transesterification with ethanol in mild conditions. It is worth noticing that differences in acid strength between anhydrous Keggin heteropolyacids, H3PW12O40, H4SiW12O40, H3PMo12O40, H4SiMo12O40, measured by calorimetry, did not correlate simply the catalytic activity. Indeed, the proton solvation with water molecule was shown to be a crucial parameter. Then, Mo samples exhibited higher activities due to their ability to lose crystallization water at lower temperatures compared to W samples. Finally, it was shown that higher transesterification rates were obtained with ethanol than methanol in presence of HPA. |
Palabras clave : | Biodiesel Transesterification Rapeseed oil Vegetable oil Heteropolyacids |
metadata.dc.rights: | Acesso Aberto |
URI : | http://repositorio.ufba.br/ri/handle/ri/14348 |
Fecha de publicación : | 2007 |
Aparece en las colecciones: | Artigo Publicado em Periódico (Química) |
Ficheros en este ítem:
No hay ficheros asociados a este ítem.
Los ítems de DSpace están protegidos por copyright, con todos los derechos reservados, a menos que se indique lo contrario.