Synthesis of a Structured Material Based on Compact Spheres Coated with Zn or Mg Spinel

In this work, a synthesis method of coating with thin layers of MgAl2O4 or ZnAl2O4 over alpha-Al2O3 spheres were developed.The method consisted in the deposition of a primer of bohemite on the spheres, followed by the impregnation with a solution of Mg or Zn nitrates, and further thermal treatments in order to obtain MAl2O4 (M: Mg or Zn). This method was modified to improve the thickness and purity of the layer material. With this method, layers of uniform and adequate thickness and good adhesion were achieved. Pt catalysts prepared with these materials as supports displayed good catalytic performances in the n-butanedehydrogenation reaction, especially those obtained with purified supports.Fil: Bocanegra, Sonia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Ballarini, Adriana Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Scelza, Osvaldo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: de Miguel, Sergio Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentin

Modification of selectivity and carbon deposition during the initial stages of the n-butane dehydrogenation over mono and bimetallic catalysts

The initial carbon deposition and the generation of dehydrogenating selectivity during the initial steps of the reaction are investigated for Pt and PtSn catalysts supported on pure and Na-doped alumina by using a pulse technique (injection of n-butane pulses). Results demonstrate that Pt supported on pure alumina is not a proper dehydrogenation catalyst. It shows a high hydrogenolytic and cracking behavior and an important carbon formation that deactivates the catalyst. However the combined presence of tin and sodium inhibits not only the carbon deposition reactions but also the C-C breaking reactions, increasing in an important way the dehydrogenating selectivity to the different butenes to a value about 80%.Fil: Bocanegra, Sonia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET -Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica; ArgentinaFil: Scelza, Osvaldo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET -Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica; ArgentinaFil: de Miguel, Sergio Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET -Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica; Argentin

Effect of the Synthesis Method of MgAl2O4 and of Sn and Pb Addition to Platinum Catalysts on the Behavior in n-Butane Dehydrogenation

The MgAl2O4 spinels, synthesized by using two different methods (ceramic and coprecipitation), show very low acidity and good dispersion capacity of the metallic phase, these properties being suitable for the use of these materials as supports. However, MgAl2O4 cer displays higher strong acidity than MgAl2O4 cop which seems to influence the metal-support interaction, since Pt/MgAl2O4 cer catalyst shows higher metallic dispersion, lower metal particle sizes, and better catalytic behavior than the Pt/MgAl2O4 cop one. The Sn addition to Pt/ MgAl2O4 improves the performance in the n-butane dehydrogenation process, increasing the activity, stability, and selectivity to butenes. This behavior is due to the presence of important Pt-Sn interactions, mainly in bimetallic catalysts supported on MgAl2O4 cer. On the other hand, the Pb addition to monometallic catalysts does not enhance the catalytic performance in dehydrogenation. This behavior is in agreement with the characterization results of metallic phase that indicate important blocking effects in PtPb/MgAl2O4 cer catalysts, and segregation effects in PtPb/MgAl2O4 cop. In conclusion, the ceramic method of MgAl2O4 preparation provides the best support for PtSn catalysts in n-butane dehydrogenation reaction.Fil: Bocanegra, Sonia 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: Yañez, Maria Julia. 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: Scelza, Osvaldo Antonio. 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: de Miguel, Sergio Ruben. 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

Effect of the support in Pt and PtSn catalysts used for selective hydrogenation of carvone

In this paper, a study on the hydrogenation of carvone by using Pt/Al2O3, PtSn/Al2O3, PtGe/Al2O3, Pt/C and PtSn/C is reported. TPR, H2 chemisorption, XPS and test reaction results show that the addition of a second metal to Pt leads to important modifications of the structure of the metallic phase, though these modifications are different according to the nature of the support (Al2O3 or C). The activity and selectivity of these catalysts in carvone hydrogenation depend not only on the composition of the metallic phase, but also on the nature of the support. Thus, adding Sn or Ge to Pt/Al2O3 enhances the selectivity to unsaturated ketones (at a fixed carvone conversion, Xcarv = 1). When Pt is supported on activated carbon, small amounts of unsaturated alcohols are observed. The Sn addition to Pt/C sharply enhances the selectivity to carveol formation (the doubly unsaturated alcohol) reaching values close to 100% at the initial stages of the reaction. © 2001 Elsevier Science B.V.Fil: de Miguel, Sergio Ruben. 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: Román Martinez, M.C.. Universidad de Alicante; EspañaFil: Cazorla Amorós, Diego. Universidad de Alicante; EspañaFil: Jablonski, Estanislao Lorenzo. 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: Scelza, Osvaldo Antonio. 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 of Pt catalysts supported on activated carbon felts (ACF)

Activated carbon felts (ACFs) have been used as supports for Pt catalysts. The preparation was carried out by the impregnation method using chloroplatinic acid as metal precursor. The effect of impregnation time and surface chemistry of the support on the catalytic properties and the characteristics of the metallic phase have been investigated. Nitrobenzene (Nbz) hydrogenation in liquid phase at 25 °C and cyclohexane (CH) dehydrogenation in gas phase at 300 °C were used as catalytic tests. The state of platinum in reduced catalysts (at 100 and 350 °C) was studied by TPR and XPS. Oxygen surface groups only produce a slight effect on the catalytic properties. The use of low impregnation times (30 min) during the preparation of Pt/ACF leads to catalysts with Pt mainly deposited in the outer shell of the fibers, while at higher impregnation times, the metallic atoms seem to be deposited inside the pores. Pt(0) species appear in catalysts reduced at 100 °C by effect of the reducing properties of the carbon fiber exhibiting a considerable catalytic activity for Nbz hydrogenation.Fil: de Miguel, Sergio Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Vilella, Irene María Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Jablonski, Estanislao Lorenzo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Scelza, Osvaldo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Salinas Martinez de Lecea, C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Linares Solano, A.. Universidad de Alicante; Españ

Behavior of PtPb/MgAl2O4 catalysts with different Pb contents and trimetallic PtPbIn catalysts in n-butane dehydrogenation

The behavior of PtPb/MgAl2O4 catalysts in butenes production through the n-butane dehydrogenation has shown that at low contents, the Pb acts as promoter, improving the conversion and selectivity, whereas at higher contents it has a poisoning effect on the catalytic activity. The PtPb(0.25 wt%)/MgAl2O4 catalyst showed the maximum yield to butenes. The characterization results of PtPb catalysts displayed that at low Pb contents there are both dilution and electronic effects of Pb on the Pt sites. On the other hand, at high Pb contents, there is a strong blocking effect of the Pb on the active sites of Pt. In order to study the effect of the In addition in different sequences to PtPb(0.25 wt%)/MgAl2O4 catalyst, two catalysts were prepared: PtPb(0.25%)In(0.28 wt%)/MgAl2O4 and PtIn(0.28%)Pb(0.25 wt%)/MgAl2O4. The first catalyst did not show significant advantages with respect to the catalytic behavior of the PtPb(0.25 wt%)/MgAl2O4, but the second trimetallic catalyst displayed an increase of both the conversion and the selectivity. The characterization results indicated similar effects of blocking and dilution of promoters on the active sites of Pt for both trimetallic catalysts, but the best catalyst, PtIn(0.28%)Pb(0.25 wt%)/MgAl2O4, showed the highest percentages of In◦ and Pb◦, thus indicating stronger interaction between Pt, Pb and In.Fil: Bocanegra, Sonia 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: Scelza, Osvaldo Antonio. 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: de Miguel, Sergio Ruben. 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

n-Decane dehydrogenation on Pt, PtSn and PtGe supported on spinels prepared by different methods of synthesis

The catalytic performance of Pt, PtSn and PtGe supported on ZnAl2O4 obtained by mechanochemical synthesis (MS) or coprecipitation (COPR) is studied in the production of 1-decene from the n-decane dehydrogenation. The effect of preparation methods and Sn and Ge addition to Pt on the activity and selectivity was analyzed. The catalytic characterization was carried out by using XRD, Specific surface area, 2-propanol dehydration reaction, equilibrium pH, cyclohexane dehydrogenation (CHD), cyclopentane hydrogenolysis (CPH), TPR, H2 chemisorption, XPS, TPO, and TEM. Characterization studies indicate that the addition of Sn to the Pt metal phase modifies not only the catalytic properties, but deactivation and stability as well. PtSn catalysts on both spinels were more active, with lower activity fall than PtGe ones and the higher the Sn loading, the more noticeable this effect. Besides, PtSn catalysts supported on ZnAl2O4 MS showed a more stabilizing effect.Fil: Ballarini, Adriana Daniela. 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: de Miguel, Sergio Ruben. 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: Castro, Alberto Antonio. 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: Scelza, Osvaldo Antonio. 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

N-decane dehydrogenation on bimetallic PtSn and PtGe catalysts prepared by dip-coating

The catalytic performance of Pt, PtSn and PtGe supported on γ-Al 2O3 (γ-A) deposited by dipcoating of spheres of α-Al2O3 (α-A) was studied in the n-decane dehydrogenation. The effect of Sn and Ge addition to Pt on the activity and selectivity was analyzed. The catalytic characterization was carried out using cyclohexane dehydrogenation (CHD), cyclopentane hydrogenolysis (CPH), temperature-programmed reduction (TPR), hydrogen chemisorption, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and scanning electronic microscopy (SEM). Pt(0.5)Sn/γ-A/α-A catalyst had the best catalytic performance and showed a low electronic interaction between the metals, with a surface segregation of Sn and the presence of oxidized Sn stabilized on the support. PtGe catalysts presented strong interactions with probable alloy formation. The catalytic performance of these catalysts is comparable to that reported in the patents.Fil: Ballarini, Adriana Daniela. 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: de Miguel, Sergio Ruben. 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: Castro, Alberto Antonio. 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: Scelza, Osvaldo Antonio. 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

Pt, PtSn and PtGe catalysts supported on granular carbon for fine chemistry hydrogenation reactions

Two series of PtSn and PtGe catalysts with different metallic loadings, supported on activated carbon powder, were prepared by successive impregnation. Both the effects of the second metal addition and the Sn or Ge loading on the activity and selectivity in the carvone and the citral hydrogenations (used as catalytic tests) were investigated. In all cases the support was purified to eliminate undesirable elements such as sulfur and, for high Pt loadings, carbon was functionalized with nitric acid so as to introduce more oxygen-containing groups. The carvone hydrogenation was carried out with PtSn catalysts, the Pt and Sn loadings being very low. The citral hydrogenation was carried out with PtSn and PtGe catalysts with higher metal loadings supported on both purified, and purified and functionalized carbons. Besides, the effect of the branched solvent in the activity and selectivity of the citral hydrogenation reaction was also studied with PtSn catalysts. The catalysts were characterized by temperature-programmed reaction (TPR), test reactions of the metallic phase (cyclohexane dehydrogenation and cyclopentane hydrogenolysis), hydrogen chemisorption and by X-ray photoelectron spectroscopy (XPS). The catalytic activity in the carvone hydrogenation showed a maximum for the monometallic catalyst with respect to the Sn loading. For the catalyst with the highest tin loading (0.4 wt%) even though the activity drastically decreased, the selectivity to the doubled unsaturated alcohol (carveol) was very important. Although the citral hydrogenation gave very good results with PtSn systems with high metallic loadings, the opposite happened with the PtGe ones. Moreover, the more branched solvents modified the selectivity to unsaturated alcohols of the PtSn catalyst in the citral hydrogenation.Fil: Vilella, Irene María Julieta. 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: de Miguel, Sergio Ruben. 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: Scelza, Osvaldo Antonio. 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

n-Butane Dehydrogenation on PtSn Supported on MAl2O4 (M: Mg or Zn) Catalysts

A study about the performance of PtSn supported on MAl2O4 (M: Mg or Zn) catalysts with low metals loadings (0.3 wt.% Pt, 0.3–0.5 wt.% Sn) in n-butane dehydrogenation is reported in this paper. Catalysts were tested in flow and pulse equipments. Besides, reaction-regeneration cycles were performed in order to determine the catalytic stability. Results showed that the Sn addition enhances the catalytic properties, the influence being almost negligible for both supports when the Sn content increases from 0.3 to 0.5 wt.%. The bimetallic formulations supported on MgAl2O4 showed a better stability in the reaction-regeneration cycles than those supported on ZnAl2O4, this behavior being related to a higher stability of the metallic phase of the PtSn/MgAl2O4 catalysts after the cycles as TPR results show.Fil: Bocanegra, Sonia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: de Miguel, Sergio Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Castro, Alberto Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Scelza, Osvaldo Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentin