UTN- FRC -Producción Académica de Investigación y Desarrollo - Artículos

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Author: search.filters.author.Anunziata, Oscar AlfredoEnd date: 2019

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    Aniline adsorption and polymerization over gallium modified mesoporous material.
    (Universidad Tecnológica Nacional., 2018) Martínez , María Laura; Rivoira , Lorena Paola; Beltramone, Andrea Raquel; Anunziata, Oscar Alfredo; Anunziata, Oscar Alfredo; Rivoira , Lorena Paola
    In this work we study aniline polymerization over a mesoporous Ga-SBA-3 synthesized in our laboratory. In order to modify the intrinsic acidity of the mesoporous material gallium was incorporated into the structure by post synthesis wet impregnation method using gallium nitrate. Structural and textural characterization of the materials was performed by X-ray diffraction (XRD), ICP and EDX analysis, N2 adsorption-desorption and BET area analysis, FTIR and scanning electron microscopy (SEM). The catalytic material presented a ratio Si/Ga=32. Aniline is a weak organic base and an amphiprotic compound, so it can accept or donate protons. The polyaniline (PANI) exists in diverse ways presenting different chemical and physical properties. The protonated polyaniline feature the conductivity of a semiconductor material, over 100 S/cm. Toward achieve aniline adsorption, the solid gallium silicate was exposed to aniline vapours. The aniline adsorption was studied by infrared spectroscopy and the results obtained were evaluated so as to been able to polymerize it over the mesoporous material generating a unique polyaniline-host composite with new properties. Those polyaniline/hosts composites obtained by a polymerization in-situ technique were characterized by infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. Comparing to previous results FTIR analysis of the polyaniline/Ga SBA-3 composite (PANI/Ga-SBA-3) showed characteristics bands attributed to the quinoidal stretching (N=Q=N) and C-C stretching of the benzene ring. The low angle XRD analysis showed that the mesoporous structure was maintained in spite of the gallium incorporation. The absence of PANI peaks and G2O3 in the wide angle XRD pattern confirms that the polyaniline is adsorbed over the gallium silicate mesoporous surface and the gallium is well dispersed over the support.
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    Optimization of the synthesis of SBA-3 mesoporous materials by experimental design
    (Elsevier Inc., 2016-02-18) Ponte, María Virignia; Rivoira, Lorena Paola; Cussa, Jorgelina; Martínez, Maria Laura; Beltramone, Andrea Raquel; Anunziata, Oscar Alfredo
    SBA-3 mesoporous materials are characterized by hexagonal regular arrangements of channels with diameters >2 nm, high specific surface areas and high specific pore volumes. In the work reported herein, experimental design-response surface methodology (RSM) is used to model and optimize the synthesis conditions for SBA-3 mesoporous materials. In this study, we evaluate the influences of surfactant/silica source molar ratios, aging times, temperature and pH on the synthesis of SBA-3 mesoporous materials by analyzing the XRD intensities pertaining to the [100] signal. Response surfaces were obtained using the BoxeBehnken design, and the combination of reaction parameters was optimized. By applying statistical methodology, higher levels of the objective function (XRD intensities pertaining to the [100] signal) were obtained using cetyltrimethylammonium bromide (CTAB)/tetraethyl orthosilicate (TEOS) molar ratios of 0.07 and 0.16, HCl/TEOS molar ratios of 8 and 11, reaction temperatures of 35 and 45 ◦C and aging times of 12e24 h. The mesoporous SBA-3 samples obtained were characterized using small-angle X-ray powder diffraction (XRD), BET, FTIR and 29Si NMR-MAS, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
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    Nanostructured ketorolac-tromethamine/MCF: synthesis, characterization and application in drug release system
    (Current Nanoscience, 2018) Juárez, Juliana María; Cussa, Jorgeliba; Gómez Costa, Marcos Bruno; Anunziata, Oscar Alfredo
    Controlled drug delivery systems can maintain the concentration of drugs in the exact sites of the body within the optimum range and below the toxicity threshold, improving therapeutic efficacy and reducing toxicity. Mesostructured cellular foam (MCF) material is a new promising host for drug delivery systems due to high biocompatibility, in vivo biodegradability and low toxicity.
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    LP-SBA-15, functionalized with tert-butylamine a novel controlled release system for cyclophosphamide.
    (Univesidsad Tecnológica Nacional, 2013) Juárez , Juliana María; Cussa, Jorgelina; Gómez costa , Marcos Bruno; Anunziata, Oscar Alfredo; Anunziata, Oscar Alfredo
    Controlled drug administration systems can keep the level of drugs in specific locations in the organism with low toxicity and above the optimal level. We suggest the LP-SBA-15 material as an auspicious new host for drug delivery systems because of its low toxicity high biocompatibility and in vivo biodegradability. LP SBA-15 materials were synthesized and functionalized using 0-15-30% of tert butylamine (TBA) and used as effective drug delivery systems. The anticancer drug Cyclophosphamide (CP) is an alkylating compound which is a phosphoramide derivative and is habitually used in autoimmune diseases. Reactive oxygen species production has been related to the mechanism of CP-induced cell death or tumor cell killing. The activated metabolites of CP are released in both healthy and tumor tissues and destroy the cellular DNA and proteins as well as mitochondrial and lysosomal membranes. CP was loaded into the nanomaterial of the transporters and characterized by XRD, FTIR, TGA, TEM and texture, determining the adsorption capacity and its release. The release of the drug was studied for each material by simulating the physiological conditions and submerging the composite, at 37 °C with constant stirring, in a HCl solution (0.1 M) for the first two hours and in Buffer solution pH = 7 the following hours to simulate the conditions of the organism. Release experiment were conducted to determine the requisite efficacy of treatment. The study was performed by UV-Vis spectrophotometry to evaluate the amount of CP released. The mechanism of drug release from the LP-SBA-15 matrix was evaluated by adjusting the experimental data, being the Ritger-Peppas (figure 1) The promising results we obtained for the controlled release of the drug in a controlled manner using the new material, reaching a quick initial release rate and maintaining a constant rate at high moments, allow us to keep the concentration of the drug in the therapeutic efficacy range, applying it to a great extent to the treatment of diseases that require a rapid response. Lastly, it was suggested that the LP-SBA-15 nanomaterial functionalized with 15% TBA was the most desirable system due to they had adequate amounts of both drug loading and release
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    Synthesis and characterization of conducting polypyrrole/SBA-3 and polypyrrole/Na–AlSBA-3 composites
    (2012) Gómez Costa, Marcos Bruno; Juárez, Juliana; Martínez, María Laura; Beltramone, Andrea Raquel; Cussa, Jorgelina; Anunziata, Oscar Alfredo
    Si-SBA-3 and Na–AlSBA-3 materials were synthesized for application in the preparation of composites. Silica mesoporous materials were obtained following the sol–gel method and post-synthesis alumination. Pyrrole-saturated hosts were prepared by adsorption of pyrrole into the mesoporous materials. The adsorption/desorption of pyrrole was studied by FTIR. Molecules of pyrrole would be adsorbed through aromatic ring to the host. The polymerization technique was performed by oxidative way using different oxidizing agents, ammonium persulfate and ferric chloride, after pyrrole adsorption on both hosts. TG, FTIR, BET, XRD, SEM and TEM were used to characterize the resulting composites. These studies show that polypyrrole is generated inside the channel of the hosts; conductivity studies show that the composites exhibit conductivities at room temperature and in the range of 1 × 10—7 and 1 × 10—6 S cm—1 depending on the host and the oxidizing agents.
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    Hydrogenation of tetralin over Ir catalysts supported on titania-modified SBA-16
    (2014) Ledesma, Brenda; Vallés, Verónica; Rivoira, Lorena Paola; Martínez, María Laura; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel
    Abstract A series of Ti modified SBA-16 supports and their respective Ir-catalysts were prepared and character- ized to study the effect of support preparation method on the dispersion of iridium and on the characteristics of Ir surface species. Two methods of incorporation of titania were tested: the sol–gel method in order to obtain Ti as heteroatom and incipient wetness impregnation to obtain Ti as TiO2 (anatase phase). The results show that supports with different Ti species and dispersion can be obtained. The final catalyst was characterized at different preparation stages by XRD, elemental analysis and BET. The presence of Ti as Ti4? in the nanostructure of SBA and as TiO2 (anatase phase) was analyzed by UV–Vis–DRS and Raman spectroscopy. The iridium oxidation sate upon Ti-con- taining SBA-16 was studied by XPS, EDX, TEM and XRD, arriving at the good proportion of Ir0. H2 chemi- sorption and TEM characterization for Ti-SBA-16 indi- cated that Ir particle size was lower than anatase/SBA-16. The catalyst that we synthesized had good activity mea- sured in tetralin hydrogenation in presence of quinoline at mild conditions. The experimental data were quantitatively represented by a modified Langmuir–Hinshelwood-type rate equation. The preliminary results show these materials as promising catalysts for HDS/HDN reactions.
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    Synthesis and characterization of new composites: PANI/Na-AlSBA-3 and PANI/Na-AlSBA-16
    (2011) Martínez, María Laura; Luna D´Amicis, Froilán A.; Beltramone, Andrea Raquel; Gómez Costa, Marcos Bruno; Anunziata, Oscar Alfredo
    The new aluminosilicate materials (Na-AlSBA-3 and Na-AlSBA-16) were synthesized for application in the preparation of composites. Silica mesoporous materials were obtained following the sol–gel method and post-synthesis alumination. These methods were effective for the synthesis of SBA-3 and SBA-16, showing XRD patterns and other characteristics in agreement with the literature. Aniline-saturated hosts were prepared by adsorption of aniline (exposed to the equilibrium vapors from liquid aniline) into the mesoporous materials. Polyaniline/Na-AlSBA-3 (PANI-3) and polyaniline/ Na-AlSBA-16 (PANI-16) composites have been synthesized by an in situ polymerization of aniline- saturated hosts. TG, FTIR, XRD, SEM and TEM were used to characterize the resulting composites. These studies show that PANI is generated inside the channel of the hosts. PANI-16 has an amount of emeraldine salt higher than PANI-3 composite. The electrical conductivity measurements confirmed that PANI and mesoporous materials were true hybrid nanocomposites. The conductive properties of these composites were compared with those of other composites
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    Synthesis of ordered mesoporous SBA-3 materials using silica gel as silica source
    (2014) Martínez, María Laura; Ponte, María Virginia; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel
    Nanostructured materials have exceptional and highly attractive properties, including catalyst, adsor- bent, separation media and chemo sensor. Technical advances in these fields require the development of ordered porous materials with controllable structures, systematic tailoring pore architecture and the synthesis of mesoporous materials using a more economical silica source. Ordered mesoporous silica SBA-3 material has been synthesized successfully using cetyltrimethylamonium bromide (CTAB) as a structure-directing agent, NaOH and inexpensive silica gel as a silica source without additives. We studied the influence of NaOH concentration on the structure and morphology of mesoporous silica SBA-3. This variation was defined as modulus L ¼[NaOH/SiO2] ratio. The structural order of the samples was found to be greatly affected by L variations. The results suggest that, by controlling the L value (0.70–1), SBA-3 is obtained with appropriate physicochemical characteristics.
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    Hydrogenation of tetralin over Ir-containing mesoporous catalysts
    (2012) Vallés, Verónica; Balangero, Gerardo Simón; Martínez, María Laura; Gómez Costa, Marcos Bruno; Anunziata, Oscar Alfredo; Beltramone, Andrea Raquel
    The yield in fluid catalytic cracking (FCC) depends on the extent of aromatic hydrogenation in the gas oil hydrotreater. To optimize the gas oil hydrotreater, it is crucial to understand the aromatic hydrogenation reaction chemistry occurring in the gas oil hydrotreater. Gas oils, which consist of hydrocarbons in the boiling point range of 290−570 °C, contain several aromatic compounds (including three rings, two rings, and one ring). Light cycle oil (LCO), which contains large concentrations of aromatics, has a poor cetane value and, hence, by itself, is a very poor-quality diesel. Because the current regulations [on cetane and polynuclear aromatic (PNA) hydrocarbons] are not stringent, LCO is currently blended with diesel. However, it is anticipated (based on existing regulations in Europe and California) that diesel quality in the near future will be more stringently regulated in terms of cetane and aromatics. To find alternative processes, it is necessary to develop new and more active catalysts to replace the current ones. Optimal design and operation of such hydrogenation processes can be achieved through the use of reliable simulation tools; however, such tools require detailed knowledge of kinetic pathways and rates.1−3 Kinetic experiments on hydrogenation are typically performed in the gas phase under atmospheric pressure on group VIII metal catalysts. Previously, Beltramone et al.4,5 reported a detailed study and a quantitative network analysis of polynuclear aromatics aromatization at industrial conditions, and Korre and Klein6 reported an exhaustive study in a batch reactor at high pressure. Otherwise, the sulfur and nitrogen compounds found in synthetic feedstocks and heavy petroleum fractions can strongly inhibit hydroprocessing reactions through competitive adsorp- tion. The presence of these species even at low concentrations can limit the observed catalytic activity and necessitate the use Article Current processes for dearomatization use catalysts combin- ing the acidity of a support and the hydrogenation and hydrogenolysis/ring-opening activity of an incorporated metal. Hydrogenation/hydrocracking is most often practiced on cyclic molecules over primarily acidic zeolite, alumina, or silica- alumina-supported noble and other group VIII metal catalysts. Different processes have used catalysts such as NiMo, CoMo, NiW, Pt, and Pd on various supports.7−17 The dominance of the acid function can lead to cracking, and thus, a primary focus is the optimization of the acid function. In fact, it was shown recently that significant enhancements in hydrogenation can be made by focusing on the metal function. The metal function is usually provided by Pt and/or Pd, but it has been shown that Ir, Ru, and Rh also have exceptional activities and selectivities for the target reaction of hydrogenation and, depending on the reaction conditions, selective ring-opening.18−20 Some alumina- supported transition-metal catalysts have much higher hydro- denitrogenation (HDN) and hydrodesulfurization (HDS) activities than the conventional NiMo system.21−25 For example, Rh, Ir, Ru, and Pt supported on silica or alumina are known to effectively catalyze nitrogen removal from methylamine, quinoline, or pyridine also in the reduced state.26 Noble-metal sulfides, either unsupported as bulk compounds27 or supported on active carbon,28 have been studied extensively in hydrorefining. It has been shown that transition-metal sulfides of the second and third rows such as those containing Ru, Rh, Os, and Ir are especially active during HDS reactions.27 Similarly, sulfides of Ir, Os, and Re were found to be most active in the HDN of quinoline,28 and sulfides of Ir and Pt were found to be most active in the HDN of pyridine.29 However, catalytic properties of metal deposited on alumina or other supports have been studied less frequently, and moreover, the primary attention to date has been devoted only to Ru.30 It was shown by Cinibulk and Vit́31 that the HDN of higher pressures and temperatures to obtain desired conversions. Therefore, the need for more active catalysts is crucial in this process. The development of highly active and selective hydrotreating catalysts is one of the most pressing problems facing the petroleum indu
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    Simultaneous optimization of methane conversion and aromatic yields by catalytic activation with ethane over Zn-ZSM-11 zeolite: the influence of the Zn-loading factor
    (2011) Anunziata, Oscar Alfredo; Cussa, Jorgelina; Beltramone, Andrea Raquel
    Experiment design-response surface methodology (RSM) is used in this work to model and optimize two responses in the process of activation of methane (C1) using ethane (C2) as co-reactant into higher hydro- carbons, over Zn-containing zeolite catalysts. The application of this methodology provides insights into a more comprehensive understanding of the influence attributed to from the different factors. In this study we analyze the influence of the C1 molar fraction (C1/C1 + C2), the reaction temperature and the Zn-loading factors. The responses analyzed were as follows: Y1: C1 conversion (mol% C) and Y2: aromatic hydrocarbon yields (mol% C). The response surfaces were obtained with the Box–Behnken Design, finding the best combination between the reaction parameters that allowed optimizing the process. By applying the statistic methodology, the higher levels of the two objective functions, C1 conversion of 48.6 mol% C and aromatic yields of 47.2 mol% C, were obtained employing, a higher temperature, 0.2–0.4 molar frac- tion of C1 and the catalysts with a higher Zn2+ content.