Stoichiometric adsorption complexes in H-ZSM-5

Journal Article · Mon Oct 31 23:00:00 EST 1988 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(88)90006-1· OSTI ID:6910384

Kofke, T J.G.; Gorte, R J ^[1]; Farneth, W E ^[2]

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1. Univ. of Pennsylvania, Philadelphia (USA)
2. E.I. duPont de Nemours and Company, Wilmington, DE (USA)

The authors have examined the adsorption of methanol, 2-propanol, and 2-methyl-2-propanol on H-ZSM-5 samples with silica/alumina ratios of 38, 70, and 520 using temperature-programmed desorption (TPD) and thermogravimetric analysis (TGA) to examine the effect of Al concentration on the strength of the acid sites. In agreement with the results of a previous study, a clearly defined adsorption state corresponding to a coverage of one molecule per Al atom could be identified for each of the alcohols on each of the zeolites, with the possible exception of methanol on H-ZSM-5(520). Furthermore, the unimolecular reactivities of the molecules in these 1:1 adsorption complexes are unaffected by the Al concentration. Only secondary reactions, such as the extent of the oligomerization of olefin products formed from 2-propanol and 2-methyl-2-propanol, are found to be different for the different samples. Adsorption complexes with a 1:1 stoichiometry are also observed following adsorption and evacuation of 2-propanamine and 2-propanone on several zeolite samples, showing that molecules with other functional groups also form adsorption complexes at the Al sites. These results imply that the acid sites in H-ZSM-5 are identical and are present at a concentration of one per Al atom.

• OSTI ID: 6910384
• Journal Information: Journal of Catalysis; (USA), Journal Name: Journal of Catalysis; (USA) Vol. 114:1; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

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10 SYNTHETIC FUELS
100200* -- Synthetic Fuels-- Production-- (1990-)
ADSORPTION
ALCOHOLS
ALKENES
ALUMINIUM
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CHEMICAL ANALYSIS
CONTROL
DESORPTION
ELEMENTS
GRAVIMETRIC ANALYSIS
HYDROCARBONS
HYDROXY COMPOUNDS
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ION EXCHANGE MATERIALS
MATERIALS
METALS
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ORGANIC COMPOUNDS
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PH VALUE
PROPANOLS
QUANTITATIVE CHEMICAL ANALYSIS
QUANTITY RATIO
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
TEMPERATURE CONTROL
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
ZEOLITES