Reaction of HY zeolite with molecular fluorine

Abstract At room temperature, gaseous F 2 extracts tetrahedrally coordinated aluminum from the lattice of an acid, near-faujasite HY zeolite (Si/Al≈13) and forms fluoro-hydroxy-aluminum complexes of the type Al 2 F(OH) (5− n )+ n in which Al is octahedrally coordinated. Moreover, the crystallinity of the zeolite is almost unchanged by the fluorination process. The HY dehydrated at 200°C under vacuum and treated under a F 2 pressure of 300 mbar at room temperature is practically totally dealuminated. At lower pressure the transformation is partial. The coordination shell of the complex becomes unstable at about 500°C. Upon losing ligands, octahedral Al reverts partially to the tetrahedral coordination and is partially reinserted into the lattice. At a higher temperature an amorphous alumina phase is formed. 27 Al and 19 F high-resolution solid-state NMR, FT-IR, X-ray diffraction, and temperature-programmed desorption (TPD) are the main tools used in this work.

[1]  V. Harlé,et al.  Identification of fluorine sites at the surface of fluorinated gamma-alumina by two-dimensional MAS NMR. , 2000, Solid state nuclear magnetic resonance.

[2]  D. Akporiaye,et al.  Multinuclear NMR Investigation of Al(N03)3 and Morpholine Dissolved in Water, in the Presence and Absence of HF , 1999 .

[3]  J. Saniger,et al.  Partial fluorination of γ-alumina by gaseous fluorine , 1998 .

[4]  J. Fripiat,et al.  Fluorination of USY and modification of its catalytic properties , 1997 .

[5]  L. J. Álvarez,et al.  Mechanisms of formation of extraframework Al2O3 in zeolites , 1997 .

[6]  R. Bryant,et al.  19F and 27Al n.m.r. spectroscopic study of the fluoro complexes of aluminum in aqueous solution and in zeolites: Dealumination of zeolites by fluoride ions , 1996 .

[7]  J. Girardet,et al.  Multinuclear NMR Study of Fluoroaluminate Complexes in Aqueous Solution , 1996 .

[8]  J. Fripiat,et al.  Broensted Acid Sites and Surface Structure in Zeolites: A High-Resolution 29Si NMR REDOR Study , 1995 .

[9]  J. Fripiat,et al.  Microporous characteristics of HY, H-ZSM-5 and H-mordenite dealuminated by calcination , 1995 .

[10]  J. Patarin,et al.  Synthesis and characterization of zeolite Nu-1 prepared from near-neutral fluoride aluminosilicate gels , 1994 .

[11]  J. Fripiat,et al.  Lewis Acid Sites and Surface Aluminum in Aluminas and Mordenites: An Infrared Study of CO Chemisorption , 1994 .

[12]  O. Klimov,et al.  ALUMINA-SUPPORTED SULFIDED CATALYSTS. V: EFFECT OF P AND F ON THE CATALYTIC ACTIVITY OF HYDRODESULFURIZATION SULFIDED CATALYSTS , 1994 .

[13]  J. Fripiat,et al.  Lewis Acid Sites and Surface Aluminum in Aluminas and Zeolites: A High-Resolution NMR Study , 1994 .

[14]  J. Edwards,et al.  27Al NMR, FT-IR and Ethanol-18O TPD Characterization of Fluorided Alumina , 1993 .

[15]  A. Ghosh,et al.  Acidity and activity of fluorinated mordenites , 1987 .

[16]  A. Ghosh,et al.  Fluorine-Promoted Catalysts , 1985 .

[17]  J. Klinowski,et al.  High-resolution solid-state nuclear magnetic resonance studies of dealuminated zeolite Y , 1985 .

[18]  R. Dessau,et al.  Aluminum incorporation into high silica zeolites , 1984 .

[19]  K. Nakamoto.  Infrared and Raman Spectra of Inorganic and Coordination Compounds , 1978 .

[20]  J. Bodkin.  Determination of fluorine in silicates by use of an ion-selective electrode following fusion with lithium metaborate , 1977 .

[21]  D. Breck.  Recent Advances in Zeolite Science , 1974 .

[22]  E. M. Flanigen,et al.  Molecular Sieve Zeolites-II , 1971 .

[23]  J. D. H. Donnay,et al.  Crystal data : determinative tables , 1963 .