61 |
Effect of pore diameter variation of FeW/SBA-15 supported catalysts on hydrotreating of heavy gas oil from Athabasca bitumenBoahene, Philip Effah 24 June 2011
The pore diameter of a catalyst support controls the diffusion of reactant molecules to the catalytic active sites; thus, affecting the rates and conversions of the hydrotreating reactions. Desirable textural properties of SBA-15 makes it a potential alternative to the conventionally used γ-Al2O3 support due to the fact that its pore size can be manipulated via controlling the synthesis parameters, while maintaining relatively high surface area. Larger pore diameter SBA-15 supports may facilitate the diffusion of bulky molecules as that of the asphaltenes present in the heavy petroleum fractions, making it a potential catalyst support for hydrotreating operations.
Considering the very sour nature of Canadas bitumen with high sulfur contents in the range of 2-6 wt %, the appreciably high sulfur contents particularly present in Athabasca derived heavy gas oils (about 4 wt % sulfur), the rising demand for cleaner fuels, and also the increasing stringency on environmental standards, the need for novel and improved hydrotreating catalysts cannot be overemphasized. By varying the molar ratio of hexane to ammonium fluoride, the pore channels of SBA-15 could be varied. Controlling the pore diameter of these supports via micelle swelling facilitated the production of larger pore diameter SBA-15-supported catalysts.
In this project, four mesoporous silica SBA-15 catalyst supports with pore diameters in the range of 5-20 nm were synthesized in the preliminary phase using hexane as the micelle swelling agent and subsequently utilized for the loading of 2 wt.% Fe and 15 wt.% W catalyst metals, respectively. The hexagonal mesoscopic structure of these materials were characterized using powder small-angle X-ray scattering (SAXS), N2 adsorption-desorption isotherms, TEM and SEM images. Powder XRD analysis evidenced inhomogeneous metal dispersion on the largest pore diameter catalyst. An optimum pore diameter of 10 nm was found for Cat-B and subsequently used to obtain the optimum Fe and W loadings required to achieve the best hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities.
The optimum catalyst was found to be Cat-H with metal loadings of 3 wt.% Fe and 30 wt.% W. At these loadings and temperatures of 375°C, 388°C, and 400°C, HDS activities of 53.4%, 64.1%, and 73.3% with corresponding HDN activities of 21.9%, 26.2%, and 38.3%, respectively, were recorded. Catalytic performance evaluations conducted on equal mass loading using a reference commercial γ-Al2O3-supported FeW catalyst offered HDS activities of 69.3%, 80.4%, and 89.1%, with corresponding HDN activities of 16.4%, 32.4%, and 49.3% at the same temperatures studied. However, no significant changes in HDS and HDN activities were observed for similar evaluations on volume percent metals loading basis.
Kinetic studies performed with the optimum FeW/SBA-15 catalyst suggested activation energies of 147.2 and 150.6 kJ/mol for HDS and HDN, respectively, by the Langmuir-Hinshelwoods model. Similar results were predicted by the Power Law and Multi-parameter models for HDS (129.6 and 126.7 kJ/mol, respectively), which does not conclusively make the latter model clearly stand out as the best. Data fitting by the Power Law suggested reaction orders of 2 and 1.5 for HDS and HDN, which seem to be consistent for the hydrotreatment of heavy gas oil. Finally, a long-term deactivation study spanning a period of 60 days time-on-stream showed the optimum catalyst to be stable under hydrotreating experiments conducted in a downward flow micro-trickle bed reactor at temperature, pressure, liquid hourly space velocity (LHSV), and gas/oil ratio of 375400˚C, 8.8 MPa, 1h-1, and 600 mL/mL (at STP), respectively.
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Effect of pore diameter variation of FeW/SBA-15 supported catalysts on hydrotreating of heavy gas oil from Athabasca bitumenBoahene, Philip Effah 24 June 2011 (has links)
The pore diameter of a catalyst support controls the diffusion of reactant molecules to the catalytic active sites; thus, affecting the rates and conversions of the hydrotreating reactions. Desirable textural properties of SBA-15 makes it a potential alternative to the conventionally used γ-Al2O3 support due to the fact that its pore size can be manipulated via controlling the synthesis parameters, while maintaining relatively high surface area. Larger pore diameter SBA-15 supports may facilitate the diffusion of bulky molecules as that of the asphaltenes present in the heavy petroleum fractions, making it a potential catalyst support for hydrotreating operations.
Considering the very sour nature of Canadas bitumen with high sulfur contents in the range of 2-6 wt %, the appreciably high sulfur contents particularly present in Athabasca derived heavy gas oils (about 4 wt % sulfur), the rising demand for cleaner fuels, and also the increasing stringency on environmental standards, the need for novel and improved hydrotreating catalysts cannot be overemphasized. By varying the molar ratio of hexane to ammonium fluoride, the pore channels of SBA-15 could be varied. Controlling the pore diameter of these supports via micelle swelling facilitated the production of larger pore diameter SBA-15-supported catalysts.
In this project, four mesoporous silica SBA-15 catalyst supports with pore diameters in the range of 5-20 nm were synthesized in the preliminary phase using hexane as the micelle swelling agent and subsequently utilized for the loading of 2 wt.% Fe and 15 wt.% W catalyst metals, respectively. The hexagonal mesoscopic structure of these materials were characterized using powder small-angle X-ray scattering (SAXS), N2 adsorption-desorption isotherms, TEM and SEM images. Powder XRD analysis evidenced inhomogeneous metal dispersion on the largest pore diameter catalyst. An optimum pore diameter of 10 nm was found for Cat-B and subsequently used to obtain the optimum Fe and W loadings required to achieve the best hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activities.
The optimum catalyst was found to be Cat-H with metal loadings of 3 wt.% Fe and 30 wt.% W. At these loadings and temperatures of 375°C, 388°C, and 400°C, HDS activities of 53.4%, 64.1%, and 73.3% with corresponding HDN activities of 21.9%, 26.2%, and 38.3%, respectively, were recorded. Catalytic performance evaluations conducted on equal mass loading using a reference commercial γ-Al2O3-supported FeW catalyst offered HDS activities of 69.3%, 80.4%, and 89.1%, with corresponding HDN activities of 16.4%, 32.4%, and 49.3% at the same temperatures studied. However, no significant changes in HDS and HDN activities were observed for similar evaluations on volume percent metals loading basis.
Kinetic studies performed with the optimum FeW/SBA-15 catalyst suggested activation energies of 147.2 and 150.6 kJ/mol for HDS and HDN, respectively, by the Langmuir-Hinshelwoods model. Similar results were predicted by the Power Law and Multi-parameter models for HDS (129.6 and 126.7 kJ/mol, respectively), which does not conclusively make the latter model clearly stand out as the best. Data fitting by the Power Law suggested reaction orders of 2 and 1.5 for HDS and HDN, which seem to be consistent for the hydrotreatment of heavy gas oil. Finally, a long-term deactivation study spanning a period of 60 days time-on-stream showed the optimum catalyst to be stable under hydrotreating experiments conducted in a downward flow micro-trickle bed reactor at temperature, pressure, liquid hourly space velocity (LHSV), and gas/oil ratio of 375400˚C, 8.8 MPa, 1h-1, and 600 mL/mL (at STP), respectively.
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Synthesis And Characterization Of Co-pb/sba-15 Mesoporous CatalystsAkca, Burcu 01 September 2006 (has links) (PDF)
Co and Pb are soft oxides, making them useful in partial oxidation catalysis. But it is
difficult to prepare high surface area, nanometer size particles due to the low melting
point of Pb. In the present study, SBA-15 samples are incorporated with Co and/or
Pb at different weight loadings to provide a controlled geometry in nanometer scale
via using direct synthesis method. The characterization of the synthesized samples
was done by XRD, N2 adsorption isotherms, TEM images and XPS analysis. The
increase in the metal loading in SBA-15 causes a decrease in the BET surface area
due to the filling of pores with metal atoms. No characteristic peaks of metal oxide
was observed up to 15 wt %Pb loading into SBA-15 in the large angle XRD pattern
indicating that metal particles are dispersed in the SiO2 structure without
accumulating and forming crystals. However, 20 wt%Pb loaded SBA-15 showed
more appreciable characteristic peaks, indicating appreciable quantities of crystallites
of metal oxide on the surface of silica. The introduction of high amount of cobalt and
lead oxides to SBA-15 resulted in the loss of long range order of pores according to
the low angle XRD patterns. The hexagonal structure of pores of SBA-15 was
v
confirmed by TEM images for all samples. XPS analysis indicated that binding
energies of O 1s and Si 2p are almost similar in Co or Pb loaded samples, while
mixed oxide loaded samples showed slightly higher binding energies which means
the structure grows into a different type.
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Synthesis Of Sba-15 And Incorporation Of Cobalt Oxide NanoparticlesSen, Ebubekir 01 October 2006 (has links) (PDF)
Mesoporous materials attracted great interest due to their huge surface area and adjustable pore sizes. One of the important mesoporous materials is SBA-15 and has larger pore size, hydrothermal stability and thicker walls than other
mesoporous materials. In this study, SBA-15 is synthesized by using sol-gel technique and cobalt oxide nanoparticles are incorporated in mesochannels by direct method.
SBA-15 was produced from the self-assembly of non-ionic triblock co-polymer (Pluronic 123) and tetra ethyl ortho silicate (TEOS). Then cobalt chloride and cobalt nitrate were added at different loading ratios with two different addition
sequences / after polymer and after TEOS. The loading ratios are in Si/Co mols and these ratios are / 15, 10, 5, 3, 1.5, 1 and 0.75 in increasing cobalt amount loaded.
Characterization of the produced materials was performed by Powder X-Ray Diffraction (PXRD), Infrared (FTIR) analysis. Nitrogen Phisisorption measurements (BET and BJH Methods) were used to examine the textural properties of produced materials. By means of Transmission Electron Microscopy (TEM) the micro structures of materials were investigated.
From the PXRD studies it is observed that the long range order of pores is preserved at even high loading amounts for cobalt chloride addition after TEOS. Co3O4 (JCPDS card no: 42-1467) crystallites are observed for Si/Co mol loading ratios 3, 1.5, 1 and 0.75. Above these loading ratios cobalt oxide is
highly dispersed in SBA-15-type structure. FTIR studies revealed the formation of condensed silica network. From the Nitrogen Phisisorption measurements it is observed that addition of cobalt salt decreases the BET surface area of produced materials. All Nitrogen Adsorption-Desorption
Isotherms are Type-IV, and has H-1 hysteresis which is a fulfillment of mesoporous structures according to IUPAC classification. BET surface area of samples loaded with cobalt chloride after TEOS possessed higher surface area than other samples. TEM images proved that at loading ratios above 3 there were not any cobalt oxide nanoparticles, cobalt oxide is highly dispersed on silica surface whereas at loading ratios 3 and below there were cobalt oxide nanoparticles embedded in the mesochannels for the samples prepared by addition of cobalt chloride after TEOS.
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Methane Activation Via Bromination Over Sulfated Zirconia/sba-15 CatalystsDegirmenci, Volkan 01 November 2007 (has links) (PDF)
Methane activation with bromine followed by the condensation of the methyl bromide into higher hydrocarbons or oxygenates is a novel route. However, the selective production of monobrominated methane (CH3Br) at high conversions is a crucial prerequisite. A reaction model was developed according to the kinetic data available in the literature and thoroughly studied to investigate the optimum reactor conditions for selective methane bromination in gas phase. It was concluded that at high methane (> / 90%) conversions dibromomethane synthesis was favored at high selectivity (~90%) under the following conditions: T=330 ° / C, Br:CH4 = 3. Sulfated zirconia included SBA-15 catalysts were prepared and characterized for the catalytic methane activation via bromination. The SBA-15 sol-gel preparation technique was followed and the zirconium was added during the preparation in the form of ZrOCl2· / 8H2O with 5-30 mol % ZrO2 with respect to the SiO2 content simultaneously with the silicon source (TEOS). The catalysts were sulfated in 0.25 M H2SO4 solution. The zirconium contents of the catalysts were determined by elemental analysis and 15 wt. % Zr was determined as the highest amount. XRD analysis showed the crystalline zirconia peaks only for high zirconia loadings (> / 25 mol % ZrO2) indicating the good distribution of Zr in silica framework at lower loadings. BET surface areas of the sulfated catalysts are in the range of 313-246 m2/g. The porous structures of the catalysts were determined by TEM
pictures, which revealed that the increase in Zr content decreased the long range order of pore structure of SBA-15 in agreement with XRD results. The acidities of the catalysts were determined by 1H MAS NMR experiments. Brø / nsted acidity was identified by a sharp 1H MAS NMR line at 10.6 ppm. The highest acidity was observed at 5.2 wt. % Zr loading according to 1H MAS NMR experiments. 29Si MAS NMR analysis showed the formation of Si-O-X linkages (X=H, Zr). Further characterization of Brø / nsted acidity was performed by FT-IR spectroscopy of adsorbed CO at 82 K. The analysis
revealed that the Brø / nsted acidity of sulfated catalysts were similar to the acid strength of the conventional sulfated zirconia. In TPD experiments, the basic molecule isopropylamine (IPAm) was adsorbed and decomposition
temperature of IPAm was monitored. The temperature decreased from 340 ° / C to 310 ° / C in sulfated catalysts, indicating the acidic character of these samples.
Catalytic methane bromination reaction tests were performed in a quartz tubular reactor. The results showed that 69% methane conversion was attainable over SZr(25)SBA-15 catalyst at 340 ° / C. The liquid 1H NMR measurements of the products revealed that > / 99% methyl bromide selectivity
was achieved.
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Synthesis Of Mesoporous Catalysts And Their Performance In Pyrolysis Of PolyethyleneAydemir, Bugce 01 December 2010 (has links) (PDF)
Plastic materials are widely used throughout the world due to their low prices and easy processing methods. A serious problem of environmental pollution is brought with the widespread use of these materials due to their non-biodegradabilty. For this reason, plastic materials are degraded into lower molecular weight liquid and gaseous products which are potential raw materials and fuels for petrochemical industry. The use of catalysts enhances the formation of more valuable hydrocarbons at lower reaction temperatures and residence times.
In this study, aluminum containing MCM-41 and tungstophosphoric acid (TPA) loaded SBA-15 materials were synthesized by impregnation of Al and TPA into hydrothermally synthesized MCM-41 and SBA-15, respectively to be used in catalytic degradation of polyethylene. Al was incorporated into MCM-41 framework with different Al/Si ratios using aluminum triisopropylate as the aluminum source and TPA was incorporated to the porous framework of SBA-15 with different W/Si ratios, using tungstophosphoric acid hydrate as the acid source.
From XRD analysis, it was observed that introducing acidic compounds did not cause deformations in the regularity and by EDS analysis, it was found out that at lower loadings, acidic compounds were introduced more effectively for MCM-41 materials. Nitrogen adsorption-desorption isotherms showed that the synthesized materials exhibited type IV isotherms. SEM and TEM pictures showed the hexagonal regularly ordered structure of SBA-15 and MCM-41 materials. FTIR analysis of the pyridine adsorbed synthesized materials revealed the existence of Lewis and Brø / nsted acid sites in the synthesized materials.
From TGA analysis it was observed that aluminum impregnated MCM-41 samples reduced the temperature of the degradation reaction significantly and TPA loaded SBA-15 samples reduced activation energy of the reaction effectively.
In the degradation reaction system, non-catalytic and catalytic degradation experiments of polyethylene were performed. In non-catalytic degradation and catalytic degradation reactions carried out using aluminum containing MCM-41 materials, selectivity of C3 and C4 hydrocarbon gases was high and in catalytic degradation reactions carried out using TPA impregnated SBA-15 materials, selectivity of ethylene was high. In the liquid analysis of non-catalytic degradation reactions, it was observed that the product distribution was mainly composed of hydrocarbons greater than C18. The use of aluminum loaded MCM-41 and TPA loaded SBA-15 materials resulted in a liquid product distribution in the range of C5-C14, which is the hydrocarbon range of gasoline fuel.
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Surface Functionalization Of Sba - 15 Particles For Amoxicillin DeliverySevimli, Filiz F. 01 September 2011 (has links) (PDF)
There are several studies in order to control drug delivery, decrease the toxicity of drugs and
also for novel biomedical applications. It is necessary to be able to control the release of the
drug within the body by using drug delivery systems. Mesoporous silica compounds have
only been discovered twenty years ago and they have already attracted many researchers to
study these materials for several applications. SBA-15 particles have a highly ordered
regular structure and are a good matrix for guest-host applications. The aim of this study is to
be able to address whether the surface functionalization of SBA-15 samples would improve
the loading of a drug into these particles. The synthesized SBA-15 particles were surface
functionalized by post - grafting synthesis method in order to be used as carrier materials for
drug delivery. Amoxicillin was used as a model drug. These mesoporous materials have been
characterized using X-ray diffraction (XRD), small-angle X-ray spectroscopy (SAXS), fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM),
N2 adsorption/ desorption, solid-state silicon nuclear magnetic resonance (Si-NMR), high-performance
liquid chromatography (HPLC), ultra-violet (UV) spectroscopy, elemental and
thermo gravimetric analysis (TGA). The effect of concentration difference and the type of
alkoxysilanes used for the functionalization have been discussed in terms of loading
amoxicillin and controlling the delivery. Drug delivery systems have many further
applications that still need to be investigated in areas such as neurosciences, cancer and
biomedical engineering.
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Hydrogen Generation From Conventional Fuels Over Mesoporous Mixed Oxide Catalysts Under Time Interrupted Reaction ConditionsCan, Mukaddes 01 April 2011 (has links) (PDF)
In this study, catalytic activity of the Co and/or Pb-SBA-15 mesoporous catalysts in methane partial oxidation reaction was investigated. By using sol-gel, incipient wetness impregnation and post grafting method, SBA-15 samples are incorporated with Co and/or Pb at different weight loadings to provide a controlled geometry in nanometer scale. The characterization of the synthesized samples was done by XRD, N2 adsorption isotherms, FTIR, TEM images, Raman and XPS analysis. In the present study also, gas phase methane partial oxidation modeling and the synthesizing of mesoporous SBA-15 silica with different pore sizes were investigated.
For the samples prepared by sol-gel method, XRD analysis showedthat cobalt exists in the form of Co3O4and Pb exist in the form of PbO. BET surface areas of the Co loaded catalysts are in the range of 479.5-640.1 m2/g. However, in Pb loaded samples, higher metal loading decrease the surface area up to 4.63 m2/g. Considering the both Co and Pb containing bi-metallic samples, TEM and BET results revealed that the ordered hexagonal mesostructure was fully destroyed.
The samples prepared by incipient wetness impregnation and post grafting method characterized by using BET, TEM, Raman and XPS analysis. According to the BET results all the samples show ordered mesostructure in agreement with TEM results for all Co and/or SBA-15 mesoporous samples. TEM results also revealed that, the Co(5%) Pb(5%)-SBA-15 catalyst prepared by incipient wetness impregnation method possess big cobalt and lead oxide crystallines on the mesoporous structure. Raman analysis results indicated that cobalt exist in Co3O4 form. According to XPS results all samples containing cobalt include Co3O4.
The partial oxidation of methane was carried out in a fixed bed flow-type reactor in a temperature range of 50&ndash / 850° / C under atmospheric pressure.According to the reaction test results, the 0.5%Rh-Co-SBA15 catalyst shows the highest methane conversion (82%) and H2 selectivity. The non-precious metal show lower reactivities, addition of Pb to the Co-SBA-15 catalyst increases the catalytic activity and decrease the H2 production temperature.
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S?ntese e caracteriza??o de materiais mesoporosos para a captura de CO2: influ?ncia do ?xido de n?quel / Synthesis and characterization of mesoporous materials for CO2 capture: influence of nickel oxide. thesis of doctorateNascimento, Alexsandra Rodrigues do 23 September 2014 (has links)
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Previous issue date: 2014-09-23 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Diversos materiais est?o atualmente em estudo para o processo de captura de CO2, a
exemplo dos ?xidos met?licos e ?xidos met?licos mistos, ze?litas, materiais carbon?ceos,
estruturas metal-org?nicas (MOF?s), organos?lica e superf?cies de s?lica modificadas. Neste
trabalho, analisou-se a capacidade de adsor??o de CO2 em materiais mesoporosos de
diferentes estruturas, como o MCM-48 e SBA-15, sem impregna??o e impregnados com
n?quel nas propor??es 5 %, 10 % e 20 % (m/m), denominados como 5Ni-MCM-48, 10NiMCM-48,
20Ni-MCM-48 e 5Ni-SBA-15, 10Ni-SBA-15, 20Ni-SBA-15. Os materiais foram
caracterizados atrav?s das an?lises de difra??o de raios X (DRX), an?lise t?rmica (TG e
DTG), espectroscopia na regi?o do infravermelho com transformada de Fourier (FT-IR),
adsor??o e dessor??o de N2 (BET) e microscopia eletr?nica de varredura (MEV) com EDS. O
processo de adsor??o foi realizado variando-se a press?o de 100 - 4000 kPa e mantendo-se a
temperatura constante e igual a 298 K. Na press?o de 100 kPa, as maiores concentra??es de
adsor??o ocorreram para os materiais 5Ni-MCM-48 (0,795 mmol g-1
) e SBA-15 (0,914 mmol
g
-1
) n?o impregnado, e, na press?o de 4000 kPa, para os materiais MCM-48 (14,89 mmol g-1
)
e SBA-15 (9,97 mmol g-1
) n?o impregnados. Os resultados mostraram que a capacidade de
adsor??o varia positivamente com a ?rea espec?fica, no entanto, apresenta uma depend?ncia
direta com o tipo e geometria dos canais da estrutura porosa. Os dados obtidos foram
ajustados atrav?s dos modelos de Langmuir e Freundlich e os par?metros termodin?micos
avaliados foram energia livre de Gibbs e entropia do sistema de adsor??o / Several materials are currently under study for the CO2 capture process, like the metal
oxides and mixed metal oxides, zeolites, carbonaceous materials, metal-organic frameworks
(MOF's) organosilica and modified silica surfaces. In this work, evaluated the adsorption
capacity of CO2 in mesoporous materials of different structures, such as MCM-48 and SBA-
15 without impregnating and impregnated with nickel in the proportions 5 %, 10 % and 20 %
(m/m), known as 5Ni-MCM-48, 10Ni-MCM-48, 20Ni-MCM-48 and 5Ni-SBA-15, 10NiSBA-15,
20Ni-SBA-15. The materials were characterized by means of X-ray diffraction
(XRD), thermal analysis (TG and DTG), Fourier transform infrared spectroscopy (FT-IR), N2
adsorption and desorption (BET) and scanning electron microscopy (SEM) with EDS. The
adsorption process was performed varying the pressure of 100 - 4000 kPa and keeping the
temperature constant and equal to 298 K. At a pressure of 100 kPa, higher concentrations of
adsorption occurred for the materials 5Ni-MCM-48 (0.795 mmol g-1
) and SBA-15 (0.914
mmol g-1
) is not impregnated, and at a pressure of 4000 kPa for MCM-48 materials (14.89
mmol g-1) and SBA-15 (9.97 mmol g-1) not impregnated. The results showed that the
adsorption capacity varies positively with the specific area, however, has a direct dependency
on the type and geometry of the porous structure of channels. The data were fitted using the
Langmuir and Freundlich models and were evaluated thermodynamic parameters Gibbs free
energy and entropy of the adsorption system
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S?ntese e caracteriza??o de complexos de base de schiff com n?quel (ii) ancorados no material mesoporoso SBA-15Maia, Danielle de Oliveira 23 July 2015 (has links)
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Previous issue date: 2015-07-23 / SBA-15 s?o materiais mesoporosos, que possuem uma rede de canais e poros de tamanho bem definido na escala nanom?trica, al?m de outras caracter?sticas, tais como, elevada estabilidade t?rmica e ?rea superficial. Essa arquitetura particular de poros torna esses materiais promissores na ?rea de ancoramento de uma variedade de compostos na matriz da s?lica resultando em aplica??es nas diversas ?reas, dentre elas, na cat?lise. Nesse trabalho, foram sintetizados complexos de Base de Schiff com n?quel (II) para serem ancorados na SBA-15 funcionalizada com 3-cloropropiltrimet?xisilano realizando um estudo da estabilidade t?rmica desses compostos. Ap?s a s?ntese dos complexos, estes foram caracterizados por an?lise elementar (CHN), ponto de fus?o, condutividade, susceptibilidade magn?tica, espectroscopia de absor??o na regi?o do UV-vis?vel, espectroscopia de absor??o na regi?o do infravermelho e an?lises t?rmicas (TG/DTG). A an?lise elementar sugere que os complexos apresentam as seguintes f?rmulas qu?micas gerais: [Ni(C18H19N3O2)].2CH3COO.H2O, [Ni(C20H23N3O2)(2Cl)].2H2O, [Ni(C19H20N3O2)(2Cl)].3H2O, sendo L1= C18H19N3O2, L2= C20H23N3O2, L3 = C19H20N3O2. Na espectroscopia de absor??o na regi?o do UV - vis?vel e infravermelho dos complexos foi evidenciada a coordena??o metal - ligante. Ap?s caracteriza??o dos complexos, estes foram ancorados no material mesoporoso. A caracteriza??o desses materiais foi realizada por difra??o de raios - X, fluoresc?ncia de raios - X, adsor??o e dessor??o de N2, espectroscopia de absor??o na regi?o do infravermelho e an?lises t?rmicas (TG/DTG). No DRX foram observados tr?s picos principais de difra??o, cujos ?ndices de Miller s?o (100), (110) e (200), mostrando que mesmo ap?s a ancoragem, os materiais mesoporosos n?o perderam suas caracter?sticas estruturais. As porcentagens dos elementos (n?quel, cloro e s?lica) encontrados nos materiais atrav?s da an?lise de fluoresc?ncia de raios - x mostraram que os complexos foram ancorados nos poros da s?lica. Atrav?s da adsor??o e dessor??o de N2, foram observadas que os materiais apresentaram isoterma do tipo IV e histerese do tipo H1 caracter?sticos dos materiais mesoporos. Na espectroscopia de absor??o na regi?o do infravermelho, os materiais ancorados apresentaram bandas caracter?sticas dos ligantes (Base de Schiff) e da s?lica evidenciando o sucesso da ancoragem. Na an?lise t?rmica, foram observadas a decomposi??o de ?gua adsorvida, ?gua coordenada, aminas, arom?ticos, ligantes, cloropropiltrimet?xisilano e o aumento na estabilidade t?rmica das s?licas ancoradas com complexos comparado ao complexo livre. / SBA-15 are mesoporous materials, having a network of channels and well defined
pore size in the nanometer range, as well as, other features such as high thermal stability and
surface area. This particular pore architecture makes these promising materials in the anchoring
area of a variety of compounds in the silica matrix resulting in applications in various
fields, among them, in catalysis. In this work, complexes were synthesized Schiff base with
nickel (II) to be anchored in the functionalized SBA-15 3 ? chloropropyltrimethoxysilane and
a study of the thermal stability of these compounds. After synthesis of the complexes, they
were characterized by elemental analysis (CHN), melting point, conductivity, magnetic susceptibility,
absorption spectroscopy in the UV-visible region absorption, spectroscopy in the
infrared region and thermal analysis (TG/DTG). Elemental analysis suggests that the complexes
have the general formula chemical: [Ni(C18H19N3O2)].2CH3COO.H2O,
[Ni(C20H23N3O2)(2Cl)].2H2O, [Ni(C19H20N3O2)(2Cl)].3H2O, and L1= C18H19N3O2, L2=
C20H23N3O2, L3 = C19H20N3O2. In absorption spectroscopy in UV - visible and infrared complexes
was evidenced the coordination metal - ligand. After characterization of the complexes,
confirming the metal - ligand coordination, they have been anchored in the mesoporous
material. The characterization of these materials were made by x- ray diffraction, x- ray fluorescence,
N2 adsorption and desorption spectroscopy, the infrared spectroscopy and thermal
analysis (TG/DTG). XRD analysis revealed three main diffraction peaks, whose Miller indices
are (100), (110) and (200), showing that even after the anchoring, the mesoporous materials
do not lose their structural characteristics. The percentages of the elements (nickel chloride
and silica) found in the anchored materials through the x-ray fluorescence analysis showed
that the complexes were anchored in the pores of the silica. Through adsorption and desorption
of N2, we observed that the materials presented isotherm type IV and type H1 hysteresis
characteristic of mesoporous materials. In the infrared spectroscopy, the materials showed
characteristic bands of ligands (Schiff base) and silica demonstrating the success of the anchor.
In the thermal analysis (TG/DTG), there were observed the decomposition of adsorbed
water, coordinated water, amines, aromatics, ligands, chloropropyltrimethoxysilane and an
increase in thermal stability (removal of ligand) of silicas anchored [Ni(L1)]SBA-15,
[Ni(L2)SBA-15 and [Ni(L3)SBA-15 compared of free complexes, showing successful anchoring
of complex molecular sieve.
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