Stoichiometric adsorption complexes in H-ZSM-5
- Univ. of Pennsylvania, Philadelphia (USA)
- 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), Vol. 114:1; ISSN 0021-9517
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
METHANOL
ADSORPTION
PROPANOLS
ZEOLITES
SORPTIVE PROPERTIES
ALKENES
ALUMINIUM
ALUMINIUM OXIDES
DESORPTION
PH VALUE
QUANTITY RATIO
SILICA
SURFACE PROPERTIES
TEMPERATURE CONTROL
THERMAL GRAVIMETRIC ANALYSIS
ALCOHOLS
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CHEMICAL ANALYSIS
CONTROL
ELEMENTS
GRAVIMETRIC ANALYSIS
HYDROCARBONS
HYDROXY COMPOUNDS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
METALS
MINERALS
ORGANIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
QUANTITATIVE CHEMICAL ANALYSIS
SILICON COMPOUNDS
SILICON OXIDES
SORPTION
THERMAL ANALYSIS
100200* - Synthetic Fuels- Production- (1990-)