Desenvolvimento de zeólitas hierárquicas de diferentes dimensionalidades com potencial para processamento de hidrocarbonetos volumosos
The influence of secondary porosity, the dimensionality of zeolitic structures with 1D, 2D and 3D pore systems exert on the accessibility of voluminous hydrocarbons to active sites was evaluated in the present work. Y, ZSM-5 and mordenite zeolites underwent different top-down treatments to introd...
Αποθηκεύτηκε σε:
| Κύριος συγγραφέας: | |
|---|---|
| Άλλοι συγγραφείς: | |
| Μορφή: | Dissertação |
| Γλώσσα: | pt_BR |
| Έκδοση: |
Universidade Federal do Rio Grande do Norte
|
| Θέματα: | |
| Διαθέσιμο Online: | https://repositorio.ufrn.br/handle/123456789/49235 |
| Ετικέτες: |
Προσθήκη ετικέτας
Δεν υπάρχουν, Καταχωρήστε ετικέτα πρώτοι!
|
| Περίληψη: | The influence of secondary porosity, the dimensionality of zeolitic structures with 1D,
2D and 3D pore systems exert on the accessibility of voluminous hydrocarbons to active
sites was evaluated in the present work. Y, ZSM-5 and mordenite zeolites underwent
different top-down treatments to introduce secondary porosity. The analysis of X-ray
diffraction (XRD), X-ray fluorescence (XRF), Fourier Transform infrared spectroscopy
(FTIR), infrared spectroscopy of pyridine adsorption and desorption (IR-Pyridine),
textural analysis by adsorption and nitrogen desorption, scanning electron microscopy
(SEM) and nuclear magnetic resonance (NMR) prove the changes. The zeolites Y and
ZSM-5 had a high increase in the specific area, reaching values of 858 m2
/g with the
maintenance of the volume of intrinsic micropores, as well as the increase in the
concentration of Brønsted acid sites, reaching values of 625,4 and 892,7, respectively.
The mordenite zeolite showed an increase in the volume of mesopores and high
retention values, and subsistence of Brønsted acidity. The materials were applied in the
cumene cracking reaction and evaluated for catalytic accessibility and acidity influence.
The synthesized zeolites Y, ZSM-5 and mordenite proved to be efficient catalysts
reaching values of 100 % cumene conversion practically throughout the reaction time,
the selectivity of the materials was significantly high for benzene and the fraction of
hydrocarbons in the range of C4-C6. Due to the kinetic diameter of the cumene molecule
and the diameter of the pore opening of the zeolites, only ZSM-5 had influences on the
accessibility to its pore network, the others being accessible to the cumene molecule. |
|---|