Amine grafted mesoporous silica por CO2 capture

Three-aminopropyltriethoxysilane modified MCM-41 mesoporous silicas were synthesized by grafting the organic groups on the support surface, using different molar ratios of SiO2:Aminosilane. The synthesized solids were characterized by N2 adsorption, XRD, FTIR and TG-DTA. MCM-41 has a specific surface area of about 1500 m2/g, while that of the functionalized materials falls around 600 m2/g, showing a tendency to decrease as the content of the functionalizing agent grows. The N2 adsorption isotherms of pure and functionalized materials are characteristic of mesoporous type IV materials. The structural properties were studied by FTIR and XRD. TG-DTA studies allow analyzing the thermal stability of the materials and determining the deposited amine content. The aminosilane modified mesoporous silica materials increase the CO2 adsorption capacity compared to that of the pure MCM-41. The results obtained are well interpreted by Freundlich physicochemical model and the model parameters show a linear correlation with APTES molar content in the samples.Fil: Serrano, Melisa Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Cuesta Zapata, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Exactas; ArgentinaFil: Gonzo, Elio Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Parentis, Monica Liliana. Universidad Nacional de Salta. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Jujuy. Facultad de Ingeniería. Planta Piloto de Ingeniería Química; Argentin

Composite ZSM-5/MCM-41 material obtained from a green resource and its enhanced catalytic performance in the reaction of vinyl acetate and isoamyl alcohol

Composite ZSM-5/MCM-41 material has been obtained by hydrothermal synthesis of alkali-treated ZSM-5 zeolite prepared from Expanded Perlite. A two-step procedure that avoids the traditional dual template synthesis strategy and involves the use of a natural resource as a raw material has been studied. The so-obtained micro-mesoporous material was characterized by X-ray diffraction, scanning and transmission electron microscopy, N2 adsorption-desorption measurements and thermal gravimetric analysis. Surface acidity studies of adsorbed pyridine and 2,6-lutidine demonstrated that mesopores in ZSM-5/MCM-41 have dramatically enhanced their accessibility property. For determination of the catalytic activity, the H-ZSM-5/MCM-41 and a microporous H-ZSM-5 were used as catalysts for the reaction between vinyl acetate and isoamyl alcohol at 90 °C. H-ZSM-5 suffers to rapid deposition of coke and acetaldehyde diisoamyl acetal was obtained as the primary product at the beginning of the reaction, while the H-ZSM-5/MCM-41 evidenced an enhanced conversion and improved selectivity towards isoamyl acetate.Fil: Corregidor, Pablo Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Cuesta Zapata, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Acosta, Delicia Ester. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Destefanis, Hugo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentin

Acidity evolution on highly dispersed chromium supported on mesostructured silica: The effect of hydrothermal treatment and calcination temperature

Mesoporous Cr-MCM-41 catalysts were synthesized, under different hydrothermal temperatures, by the sol-gel procedure using tetraethylorthosilicate (TEOS) as silica precursor and cetyltrimethylammonium bromide (CTAB) as a structure-directing agent. Materials were characterized by several techniques (XRD, XPS, TG-DTA, FTIR, UV–Vis, AA and N2 sorptometry). The amount and accessibility of different hydroxyl groups were analyzed by FTIR spectroscopy after heat treatment in vacuum (10 5 mmHg) and subsequent exchange of hydrogen by deuterium using D2O. TG-DTA, FTIR of adsorbed pyridine and 2,6-dimethylpyridine and TPD of pyridine, let to determine the strength, thermal evolution, and amount of the different acid sites present at the surface. Results correlate with catalytic activity against 2-propanol in the gas phase, and let to propose mechanisms for dehydration and dehydrogenation reactionsFil: Cuesta Zapata, Pablo Martín. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gonzo, Elio Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta. Facultad de Ingeniería. Escuela de Ingeniería Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Parentis, Monica Liliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ingeniería. Escuela de Ingeniería Química; ArgentinaFil: Bonini, Norberto Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Química; Argentin

Acid sites development on Cr3+/SiO2 catalysts obtained by the sol-gel method and hydrothermal treatment: Effect of calcination temperature

Cr/SiO2 catalysts (4-8% Cr, w/w), obtained from Cr(III) salts and tetraethylortosilicate (TEOS), were prepared by the sol-gel method. After TEOS hydrolysis in ammoniacal solution (pH: 9.5), the gel was treated under hydrothermal conditions at 120-220 C. The solids were characterized by N 2 sorptometry, TG-DTA, DRUV-vis, XRD, and FTIR. In vacuum or N 2 atmosphere, Cr3+ ions were stable up to 450 C. However, calcination in air promotes the partial oxidation of Cr3+ to Cr 6+ as the temperature increases from 200 to 450 C. The amount of Cr6+ formed depends on the temperature of the hydrothermal treatment. 2,6-Lutidine adsorption allows to determine the evolution, with respect to calcination temperature, of both Lewis and Brönsted acid centers. Cr 3+ ions were related to the presence of Lewis sites, and Cr 6+ ions to the development of weak Brönsted acid sites. Accordingly, the 2-propanol dehydration reaction rate shows an increase when the catalysts are treated in N2 at 450 C, while catalysts calcined in air develop a lower acidity. The dehydration reaction is attributed to the presence of Lewis acid centers.Fil: Cuesta Zapata, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Parentis, Monica Liliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Gonzo, Elio Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Bonini, Norberto Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentin

Synthesis of Cu/SiO2(MCM-41) mesostructured catalysts: Effect of the preparation method on the textural properties and chemical structure

Two Cu/SiO2 mesoporous materials (Cu-MCM-41) were synthesized, one by the ion exchange (IE) post-synthesis method and the other, by the sol-gel (SG) method by co-precipitation of copper and silica (Cu-MCM-41) in the cetyltrimethylammonium bromide (CTAB) presence. The effects of the synthesis method on these materials were analyzed. They were characterized by XRD, N2 adsorption-desorption, TEM, DRUV–vis, FTIR, TPR, XPS, and FTIR with both, CO and pyridine adsorbed. Using the SG method, an MCM-41 material with a uniform mesoporous structure (Dp ≈ 35 Å), and a specific surface area (SBET) of 800 m2.g-1, was obtained. With the IE method and due to the partial collapse of the SiO2-MCM-41 mesoporous structure used as support, a material with a lower SBET (560 m2.g-1) was produced. The Cu in the SG synthesized material was mainly constituted by SiO-[CuO]n-CuOSi polymeric species and small CuO agglomerates. On the other hand, in the IE material, the copper was in the form of isolated SiO–Cu–OSi monomers, SiO–Cu–O–Cu–OSi dimers, and only a low proportion of SiO-[CuO]n-CuOSi oligomers. The catalytic activity of both materials was tested against the 2-propanol (2-PrOH) dehydrogenation in the gas phase. The reaction rate of the IE synthesized material was an order of magnitude higher than that prepared by the SG method. This behavior was attributed to the presence of SiO–Cu+ pair formed by the reduction of SiO–Cu–O–Cu–OSi dimmers present in the material prepared by IE; in contrast with the CuO aggregates obtained by the SG method.Fil: Cuesta Zapata, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Miranda, José Feliciano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Orellana, Francisco. No especifíca;Fil: Gonzo, Elio Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Bonini, Norberto Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentin

Effect of hydrothermal treatmenton Cr-SiO2 mesoporous materials

Cr/SiO2 (MCM-41) materials were prepared by the sol–gel method by hydrolysis of tetraethylortosilicate (TEOS) using cetyltrimethylammonium bromide (CTAB) as a template. The effect of hydrothermal treatment between 120–220 °C on the structural properties was studied. Well ordered Cr/MCM-41 with a very narrow pore size distribution was obtained after hydrothermal treatment from RT to 150 °C. Materials synthesized at higher temperatures (200 or 220 °C) showed the collapse of the ordered mesoestructure to give mesoporous Cr/SiO2 with an open surface. Superficial Cr3+/Cr6+ ratio was determined by XPS over materials hydrothermically synthesized at different temperatures, and calcined in air at 300 °C. The hydrothermal treatment improved the chromium to silica interaction, promoting a higher resistance to form Chromium (VI) sites. The chromium (III) ions incorporated to the silica structure developed acid sites responsible for the 2-PrOH dehydration.Fil: Cuesta Zapata, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigación Para la Industria Química (i); ArgentinaFil: Nazzarro, Marcelo Sandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Física Aplicada; ArgentinaFil: Parentis, Monica Liliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigación Para la Industria Química (i); ArgentinaFil: Gonzo, Elio Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigación Para la Industria Química (i); ArgentinaFil: Bonini, Norberto Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigación Para la Industria Química (i); Argentin

Cr/SiO2 mesoporous catalysts: Effect of hydrothermal treatment and calcination temperature on the structure and catalytic activity in the gas phase dehydration and dehydrogenation of cyclohexanol

Cr/SiO2 mesoporous materials (Cr-MCM-41) were obtained by hydrothermal synthesis. The effect of hydrothermal treatment and calcination temperature on the structure and catalytic behavior of synthesized materials were analyzed. The materials were characterized by XRD, N2 adsorption-desorption, TEM-SEM, TG-DTA, FTIR-HATR, DRUV-vis and XPS. The hydrothermal treatment promoted the incorporation of Cr3+ into the silica network, improving their resistance to oxidation. The calcination in air produces the simultaneous presence of Cr3+ and Cr6+ ions, and their relative amounts depend both on the hydrothermal pretreatment and the calcination temperatures. The Cr3+ ions constituted coordinative unsaturated acid centers responsible of the cyclohexanol to cyclohexene dehydration reaction. Moreover, the Cr6+ ions correspond to either isolated monochromate species linked to the silica structure or to polychromate aggregates, which produce crystalline α-Cr2O3 clusters after calcination in air to 450 °C. The monochromate centers were active for the dehydrogenation reaction. So, although dehydration was the main reaction, the dehydrogenation reaction to cyclohexanone also was observed after calcination in air to 450 °C.Fil: Cuesta Zapata, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Nazzarro, Marcelo Sandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Gonzo, Elio Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Parentis, Monica Liliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Bonini, Norberto Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentin

Amorphous Cr/SiO2 Materials Hydrothermally Treated: Liquid Phase Cyclohexanol Oxidation

Amorphous Cr–SiO2 materials were synthesized by the sol–gel method and hydrothermally treated at temperatures between 150 and 220 °C. These materials were used as catalysts for cyclohexanol oxidation with H2O2 as oxidant and CH3CN as a solvent. They were responsible for the decomposition of H2O2, which triggers, by a free radical mechanism in the homogeneous phase, the oxidation or degradation of the hydrocarbon chain. Metal leaching causes a drop in catalytic activity when the material is recycled. Studies on the hydrothermal treatment effect on the leaching process have demonstrated that the higher the hydrothermal treatment temperature, the higher the metal/support interaction, leading to a diminution of the leaching process. Under mild reaction conditions, and using TBHP as oxidant, leaching was reduced, and improvements were obtained on the selectivity towards the formation of cyclohexanone. The use of these catalysts in the oxidation of verbenol, an allylic alcohol, showed a significant increase in the substrate conversion and in the selectivity to carbonyl derivative formation.Fil: Miranda, José Feliciano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Cuesta Zapata, Pablo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Gonzo, Elio Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Parentis, Monica Liliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Davies, Lilian Emilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Bonini, Norberto Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentin

Performance of a modular ton-scale pixel-readout liquid argon time projection chamber

International audienceThe Module-0 Demonstrator is a single-phase 600 kg liquid argon time projection chamber operated as a prototype for the DUNE liquid argon near detector. Based on the ArgonCube design concept, Module-0 features a novel 80k-channel pixelated charge readout and advanced high-coverage photon detection system. In this paper, we present an analysis of an eight-day data set consisting of 25 million cosmic ray events collected in the spring of 2021. We use this sample to demonstrate the imaging performance of the charge and light readout systems as well as the signal correlations between the two. We also report argon purity and detector uniformity measurements, and provide comparisons to detector simulations

Performance of a modular ton-scale pixel-readout liquid argon time projection chamber

International audienceThe Module-0 Demonstrator is a single-phase 600 kg liquid argon time projection chamber operated as a prototype for the DUNE liquid argon near detector. Based on the ArgonCube design concept, Module-0 features a novel 80k-channel pixelated charge readout and advanced high-coverage photon detection system. In this paper, we present an analysis of an eight-day data set consisting of 25 million cosmic ray events collected in the spring of 2021. We use this sample to demonstrate the imaging performance of the charge and light readout systems as well as the signal correlations between the two. We also report argon purity and detector uniformity measurements, and provide comparisons to detector simulations