Publication
Title
On the synthesis of vanadium containing molecular sieves by experimental design from a $VOSO_{4}-5H_{2}O-Al(iPrO)_{3}-Pr_{2}NH-H_{2}O$ : occurrence of VAPO-41 as a secondary structure in the synthesis of VAPO-11
Author
Abstract
 An experimental design was applied to the hydrothermal synthesis of VAPO-11 molecular sieve (AEL structure) from a VOSO4. 5H(2)O . Al(iPrO)(3). Pr2NH . H2O gel. The influence of five synthesis parameters (synthesis temperature, synthesis time, vanadium content, water content and template content) on the crystallinity and physicochemical properties of the as-synthesized materials was studied. The obtained materials were characterized by electron spin resonance (ESR), diffuse reflectance spectroscopy (DRS), X-ray diffraction, thermal analysis measurements, scanning electron microscopy and in situ Fourier transform infrared (FTIR) spectroscopy. The AEL structure appears either as a single phase or as a physical mixture together with the AFO structure (VAPO-41). A statistical model is proposed, which relates the synthesis variables with the crystallinity allowing to indicate the optimal synthesis conditions for VAPO-11. Highly crystalline single-phase VAPO-11 can be best prepared at 170 degrees C from a synthesis gel with a low vanadium content (0.02 mel) and a high water content (25 mol). The co-ordination of vanadium in these materials is discussed on the basis of the ESR and DRS spectra. The spectroscopic data are explained by the presence of a vanadium species in distorted octahedral co-ordination, composed of two V-O-T bonds with the framework, one bond with the vanadyl oxygen and three water molecules as ligands. (C) 2000 Elsevier Science B.V. All rights reserved.
Language
English
Source (journal)
Microporous and mesoporous materials: zeolites, clays, carbons and related materials. - Amsterdam
Microporous and mesoporous materials
Publication
Amsterdam : 2000
ISSN
1387-1811
Volume/pages
39:3(2000), p. 493-507
ISI
000089735100008
Full text (Publisher's DOI)
Full text (publisher's version - intranet only)
UAntwerpen
 Faculty/Department Research group Publication type Subject Affiliation Publications with a UAntwerp address