Melero, Juan A.Bautista, L. FernandoMorales, GabrielIglesias, JoseSánchez-Vázquez, Rebeca2010-09-242010-09-242010Chemical Engineering Journal 161 (2010) 323-331http://hdl.handle.net/10115/4247Biodiesel production from crude palm oil containing high percentage of free fatty acids over sulfonic acid-functionalized SBA-15 materials (propyl-SO3H, arene-SO3H, perfluoro-SO3H) has been studied. The catalytic results showed that sulfonic acid-modified mesostructured materials were more active than conventional ion-exchange sulfonic resins (Amberlyst-36 and SAC-13) in the simultaneous esterification of free fatty acids and transesterification of triglycerides with methanol. The reusability of the catalysts was also investigated showing high stability for propyl-SO3H and arene-SO3H-modified mesostructured materials. In contrast, ionic exchange sulfonic acid resins displayed low conversion rates, being stronger this decay of activity in the second consecutive catalytic run. Interestingly, perfluorosulfonic acid-functionalized SBA-15 sample yielded a dramatic loss of activity indicating that Si-O-C bonding is not stable under the reaction conditions as compared with Si-C bond present in propyl-SO3H and arene-SO3H catalysts. Further functionalization of arene-SO3H SBA-15 catalyst with hydrophobic trimethylsilyl groups enhanced its catalytic performance. This material was able to produce a yield to FAME of ca. 95 % as determined by 1H NMR in four hours of reaction with a moderate methanol to oil molar ratio (20:1), 140 ºC and a catalyst concentration of 6 wt% referred to starting oil.enAtribución-NoComercial-SinDerivadas 3.0 Españahttp://creativecommons.org/licenses/by-nc-nd/3.0/es/Energías Renovablesinfo:eu-repo/semantics/article10.1016/j.cej.2009.12.037info:eu-repo/semantics/openAccess23 Química