UTN- FRC -Producción Académica de Investigación y Desarrollo - Artículoshttp://hdl.handle.net/20.500.12272/24532024-03-29T14:42:31Z2024-03-29T14:42:31ZSynthesis and characterization of new composites: PANI/Na-AlSBA-3 and PANI/Na-AlSBA-16http://hdl.handle.net/20.500.12272/102362024-03-27T21:07:32Z2011-01-01T00:00:00ZSynthesis and characterization of new composites: PANI/Na-AlSBA-3 and PANI/Na-AlSBA-16
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
2011-01-01T00:00:00ZSynthesis of ordered mesoporous SBA-3 materials using silica gel as silica sourcehttp://hdl.handle.net/20.500.12272/102332024-03-27T20:52:55Z2014-01-01T00:00:00ZSynthesis of ordered mesoporous SBA-3 materials using silica gel as silica source
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.
2014-01-01T00:00:00ZHydrogenation of tetralin over Ir-containing mesoporous catalystshttp://hdl.handle.net/20.500.12272/102292024-03-27T20:43:46Z2012-01-01T00:00:00ZHydrogenation of tetralin over Ir-containing mesoporous catalysts
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
2012-01-01T00:00:00ZSimultaneous optimization of methane conversion and aromatic yields by catalytic activation with ethane over Zn-ZSM-11 zeolite: the influence of the Zn-loading factorhttp://hdl.handle.net/20.500.12272/102262024-03-27T20:30:38Z2011-01-01T00:00:00ZSimultaneous optimization of methane conversion and aromatic yields by catalytic activation with ethane over Zn-ZSM-11 zeolite: the influence of the Zn-loading factor
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.
2011-01-01T00:00:00Z