Hidroisomerização de N-hexadecano sobre peneira molecular mesoporosa Pt/Al-SBA-15
The objective of this research was to study the reaction of hydroisomerization nhexadecane on bifunctional platinum catalyst supported on a mesoporosa molecular sieve and check its conversion and selectivity to mono branched products. The mesoporous molecular sieve Al-SBA-15 was synthesized by three...
| Autor principal: | Zanatta, Elciane Regina |
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| Formato: | Tese |
| Idioma: | Português |
| Publicado em: |
Universidade Estadual de Maringá
2019
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| Assuntos: | |
| Acesso em linha: |
http://repositorio.utfpr.edu.br/jspui/handle/1/4397 |
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| Resumo: |
The objective of this research was to study the reaction of hydroisomerization nhexadecane on bifunctional platinum catalyst supported on a mesoporosa molecular sieve and check its conversion and selectivity to mono branched products. The mesoporous molecular sieve Al-SBA-15 was synthesized by three different procedures called A, B and C. Tetraethylorthosilicate was used as silica source, aluminum isopropoxide as aluminum source, as directing agent structure of the tri-block copolymer Pluronic P123 as hydrochloric acid solution and directing structure agent. The mesoporous support obtained was characterized by atomic absorption spectrometry (EAA), X-ray diffraction (XRD), N2 adsorption/desorption measurements, temperatureprogrammed desorption of ammonia (NH3-TPD), scanning electron microscopy (SEM), nuclear magnetic resonance (NMR), Fourier transformed infrared spectroscopy (FTIR), diffuse reflectance UV-Visible spectroscopy. 0.5% m/m of platinum were incorporated using a solution of Tetraammineplatinum (II) chloride (Pt(NH3)4)Cll2), using the incipient wetness impregnation dry procedure. Samples of the Pt/Al-SBA-15 were then characterized by X-ray diffraction (XRD), N2 adsorption/desorption measurements, temperature-programmed desorption of ammonia (NH3-TPD), Fourier transformed infrared spectroscopy (FTIR), transmission electron microscopy (TEM), temperature programmed reduction (TPR-H2 ) and chemisorption and Loss on Ignition (LOI) of the catalyst. The sample catalyst Pt/Al-SBA-15 was then activated in a multipurpose unit and characterized again by transmission electron microscopy (TEM). Therefore, Pt/AlSBA-15 were evaluated by the isomerization reaction of n-hexadecane in batch reaction, observing parameters such as reaction time and temperature. The products obtained of the reaction were characterized by gas chromatography and the conversion parameters of n-hexadecane and the selectivity to products mono-branched were determined. The results obtained allow concluding that the direct synthesis of Al-SBA-15 mesoporous support is possible with the incorporation of a significant amount of aluminum, maintaining the structural characteristics. The impregnation method used for platinum metal did not alter the symmetry of the pore structure of the catalysts. The results to conversion show that reaction time of 30 hours is sufficient to achieve maximum conversion of n-C16 in the conditions used. The selectivity to methyl-pentadecanos reached a maximum during the period between 2 and 3 hours of reaction with a relative selectivity of 43%, and remained almost constant with reaction time. For temperature of 290 ° C and 5 hours of reaction the catalyst A has a 70% conversion and a selectivity to mono-branched 48%, the catalyst B shows a 31% conversion and a selectivity to monobranched 90%, the catalyst C has a 32% conversion and a selectivity to mono-branched 75%, therefore the catalyst B as selective mono-branched product, followed by the catalyst C and less selective is the catalyst A. The bifunctional classic mechanism explains the selectivity profiles for cracked products, monobranched and multibranched. |
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