[sup 27]Al NMR, GT-IR and ethanol-[sup 18]O TPD characterization of fluorided alumina

Journal Article · Mon Mar 01 04:00:00 EST 1993 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1006/jcat.1993.1070· OSTI ID:6130618

DeCanio, E C ^[1]; Bruno, J W ^[2]; Nero, V P; Edwards, J C ^[3]

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1. Texaco R D Dept., Beacon, NY (United States) Wesleyan Univ., Middletown, CT (United States)
2. Wesleyan Univ., Middletown, CT (United States)
3. Texaco R D Dept., Beacon, NY (United States)

New environmental legislation in the United States requiring reformulation of gasoline and diesel fuels is making its necessary to develop better, alternative acid catalysts for alkylation and isomerization reactions, and for hydrotreating catalysts for sulfur and nitrogen removal from refinery streams. A series of F/Al[sub 2]O[sub 3] samples (wt % F = 0 to 20) has been studied using a combination of solid-state [sup 27]Al NMR, FT-IR, and ethanol-[sup 18]O TPD techniques. Solid-state [sup 27]Al NMR is particularly sensitive to amorphous phases or small crystallites present on the catalyst surface, many of which cannot be detected by XRD. [sup 27]Al NMR shows the presence of three types of AlF[sub 3](H[sub 2]O)[sub n] species (with n varying between 0 and 3) on fluorided alumina. FT-IR studies of ethanol adsorption show that fluoride blocks the sites required for dissociative chemisorption of ethanol. A similar analysis of adsorbed pyridine shows an increase in the number of Broensted acid sites with the addition of up to 10 wt % fluoride. However, increasing the fluoride loading to 20 wt % decreases the number of Broensted acid sites. The TPD of ethanol-[sup 18]O from F/Al[sub 2]O[sub 3] samples shows that at low levels fluoride serves to block Lewis acid sites, but at higher levels its predominant role is to increase the Broensted acidity of the alumina surface. The pyridine adsorption and TPD experiments show that fluoride strengthens the remaining Lewis acid sites. 14 figs., 3 tabs.

• OSTI ID: 6130618
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 140:1; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400 -- Petroleum-- Processing
10 SYNTHETIC FUELS
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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ABSORPTION SPECTROSCOPY
ADSORPTION
ALCOHOLS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AZINES
BROENSTED ACIDS
CATALYSTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISORPTION
DESORPTION
ETHANOL
FLUORINE COMPOUNDS
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
HYDROGENATION
HYDROXY COMPOUNDS
INORGANIC ACIDS
MAGNETIC RESONANCE
NUCLEAR MAGNETIC RESONANCE
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PYRIDINE
PYRIDINES
RESONANCE
SEPARATION PROCESSES
SORPTION
SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS