DEALI - Departamento de Alimentos

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/540

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    New heterogeneous catalyst for the esterification of fatty acid produced by surface aromatization/sulfonation of oilseed cake.
    (2015) Santos, Eleonice Moreira; 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
    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.