Preparation, characterization and surface acid catalytic activity of microporous clays pillared with Al1-xFexOy (x=0.00 to 1.00) oxidic species

 
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Preparation, characterization and surface acid catalytic activity of microporous clays pillared with Al1-xFexOy (x=0.00 to 1.00) oxidic species (EN)

Stathopoulos, V. N. (EN)

Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας (EL)
Stathopoulos, V. N. (EN)

Montmorillonite was pillared with mixed oxidic species of the form Al1-xFexOy where x = 0.00, 0.05, 0.15, 0.25, 0.50, 0.75 and 100. The pillaring agent was an alkaline solution of the corresponding quantities of metal nitrates so as to obtain a final ratio (Al + Fe)/OH = 1:2. The specific surface area (BET) of the samples dried at 500 degrees C was found to be 230 +/- 10 m(2) g(-1) for x = 0.00 - 0.50 and similar to 139 +/- 8 m(2) g(-1) for x = 0.75-1.00. The XRD results obtained at low angles from samples oriented along the (001) axis showed gallery heights of the heated solids of 16-17 Angstrom for x = 0.00 - 0.50 and 9.9 - 9.8 Angstrom for x = 0.75 - 1.00. The acidity of the samples, checked by TPD of NH3, varied from similar to 12 x 10(17) sites m(-2) (x greater than or equal to 0.25) to similar to 9 x 10(17) sites m(-2) (x less than or equal to 0.75). The acid catalytic activity of the solids was checked using the isopropanol (IPA) decomposition as a probe reaction. The main products observed were propene (selectivity greater than or equal to 80%) and di-iso-propyl ether (DIPE) (selectivity less than or equal to 20%). The apparent activation energies for the TPA conversion were calculated, and the selectivity dependence on temperature was kinetically modelled. From this, a mechanism was derived to account for the reactions of one or two IPA molecules towards propene or DIPE, respectively, and the dependence of the selectivity on the Al/Fe ratio and the acidity of the solids. (C) 1999 Elsevier Science B.V. All rights reserved. (EN)

acid catalysis (EN)

Πανεπιστήμιο Ιωαννίνων (EL)
University of Ioannina (EN)

Microporous and Mesoporous Materials (EN)

Αγγλική γλώσσα

1999

<Go to ISI>://000082838400010

Elsevier (EN)



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