New heterogeneous catalyst for the esterification of fatty acid produced by surface aromatization/sulfonation of oilseed cake.

• Autor(a) principal: Santos, Eleonice Moreira
• Data de Publicação: 2015
• Outros Autores: Teixeira, Ana Paula de Carvalho, Silva, Flávia Gontijo da, Cibaka, Thérèse Ebambi, Araújo, Maria Helena, Oliveira, Willian Xerxes Coelho, Medeiros, Felipe, Brasil, Alex Nogueira, Oliveira, Leandro Soares de, Lago, Rochel Montero
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFOP
• Texto Completo: http://www.repositorio.ufop.br/handle/123456789/7006; https://doi.org/10.1016/j.fuel.2015.02.027
• topic: Acid catalyst; Oleic acid; Esterification; Biodiesel cake; Aromatization

In this work, an efficient heterogeneous acid catalyst for the esterification of oleic acid was prepared directly from oilseed cake by a simple sulfonation with concentrated H2SO4. Characterization by SEM/EDS, IR, Raman, TG, TG/MS, potentiometric titration showed that treatment with H2SO4 for 1, 2 and 4 h at 120 _C partially dehydrates the cake to form a carbon/cellulose composite which is sulfonated to produce strong ASO3H acidic sites. These surface sites were active for the esterification of oleic acid with yields ca. 84%, 88% and 94% in the presence of 5, 10 and 20 wt% catalyst, respectively. These results are comparable to 98% yield obtained with 1 wt% H2SO4 and higher than 75% observed for a high surface area (880 m2 g_1) sulfonated activated carbon with similar number of ASO3H active groups. These results are discussed in terms of two effects: (i) the number of sulfonic surface acidic groups and (ii) the presence of a hydrophilic cellulosic fraction in the catalyst that adsorbs/traps water formed in the reaction shifting the esterification equilibrium and improving the yield.