Deactivation study of Ru-Sn-B/Al2O3 catalysts during selective hydrogenation of methyl oleate to fatty alcohol

In this work, the deactivation of the Ru-Sn-B/Al2O3 catalyst prepared by the incipient wetness method in the selective hydrogenation reaction of methyl oleate to fatty alcohol was studied. There was a decrease in both the activity and selectivity of fatty alcohol during successive reaction experiments. The fresh and deactivated catalysts were evaluated by different techniques such as TPR, XPS, TGA, Raman, and FTIR to determine the deactivation causes. Lower Ru and Sn content were found in the deactivated catalyst due to the loss of the active material during hydrogenation reaction. As the metal loss was more important for Ru than for Sn, the Ru/Sn ratio was changed, leading to a decrease of the selectivity. Moreover, the analysis of the XPS peak by the deconvolution of Sn species suggests the more active (SnOx) species for selective hydrogenation are more affected than the less selective (SnOy). Coke deposition was not observed by Raman and FTIR.Fil: Sánchez, María A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Vicerich, Maria Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Mazzieri, Vanina Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Gioria, Esteban Gaston. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Gutierrez, Laura Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Pieck, Carlos Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; Argentin

Preparation and characterization oF Ru-Sn/Al2O3 catalysts for the hydrogenation of fatty acid methyl esters

Ru-Sn/Al2O3 catalysts with different Sn loadings were prepared by the coimpregnation method. Several characterization techniques such as TPR, pyridine TPD and catalytic tests for dehydrogenation and hydrogenolysis were used to evaluate and compare such catalysts. TPR results indicate that Sn is deposited both onto the support and as species strongly interacting with Ru. Such non selective deposition modifies the acid and metallic functions of the catalysts. Both total acidity and acid strength distribution are affected: total acidity decreases and new sites of lower acid strength are created. Both dehydrogenating and hydrogenolytic activities are strongly diminished by the addition of Sn. Results of catalytic tests for methyl oleate hydrogenation indicate that methyl stearate is the main product, with only minute amounts of oleyl alcohol produced, and that the addition of Sn diminishes the hydrogenation activity

Sulfur resistance of Pt-W catalysts

The sulfur resistance of low-loaded monometallic Pt catalysts and bimetallic Pt-W catalysts during the partial selective hydrogenation of styrene, a model compound of Pygas streams, was studied. The effect of metal impregnation sequence on the activity and selectivity was also evaluated. Catalysts were characterized by ICP, TPR, XRD, and XPS techniques. Catalytic tests with sulfur-free and sulfur-doped feeds were performed. All catalysts showed high selectivities (>98%) to ethylbenzene. Activity differences between the catalysts were mainly attributed to electronic effects due to the presence of different electron-rich species of Pt0 and electron-deficient species of Ptδ+. Pt0 promotes the cleavage of H2 while Ptδ+ the adsorption of styrene. The catalyst successively impregnated with W and Pt (WPt/Al) was more active and sulfur resistant than the catalyst prepared with an inverse impregnation order (PtW/Al). The higher poison resistance of WPt/Al was attributed to both steric and electronic effects.UNL, CONICET, and ANPCyT

Applied Catalysis A: General

Texto completo: acesso restrito. p. 156– 163Trimetallic Pt–Re–Ge supported catalysts for naphtha reforming were prepared by successive impregnation of suitable precursors on gamma alumina. The order of addition of these precursors was varied and its influence on the catalytic properties was assessed by means of the model reaction of n-octane reforming. It was found that the order of addition of the metal precursors greatly affects the performance and properties of these systems, which in turn is closely related to the first impregnated metal. When platinum is impregnated before rhenium and germanium the metals are reduced separately resulting in catalysts with high dehydrogenation activity and low hydrogenolysis activity. On the other hand, the impregnation of germanium before the other metals leads to the production of catalysts with low activities for dehydrogenation and high activity for hydrogenolysis, as a consequence of the strong interactions among the metals. By adding rhenium before the other metals, catalysts with intermediate behavior are produced. For all catalysts, platinum interacts more strongly with rhenium than with germanium. The order of addition does not modify the acidic properties of the support but germanium and rhenium seem to change the acidity of the support in the vicinity of the metals, causing differences in the selectivity to aromatic compounds and paraffinic isomers. These features can be used to tailor catalysts with high selectivity for the production of aromatics or isoparaffins, depending on the purpose of the reforming process. The RePtGe catalyst has the highest selectivity to branched isoparaffins and then can be used to produce isoparaffins-rich gasoline while a reformate rich in aromatics can be obtained by using the GeRePt catalyst