Investigation of the distribution of acidity in zeolites by temperature-programmed desorption of probe molecules. 1. Dealuminated mordenites

Journal Article · Thu Jan 25 04:00:00 EST 1990 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100365a047· OSTI ID:6879867

Karge, H G; Dondur, V ^[1]

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1. Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin (West Germany)

The acidity of dealuminated hydrogen mordenites (Si/Al = 12-39) is characterized by the temperature-programmed desorption of ammonia or pyridine which is monitored through a mass spectrometer. Four types of sites are indicated by ammonia desorption, viz., weak and strong sites of Broensted and Lewis type, whereas pyridine desorption reveals only the existence of three types of acidic sites which are tentatively assigned to one sort of Broensted site and weak and strong Lewis centers. Evaluation of the desorption spectra provides the temperatures of maximum rate of desorption, the population of the respective sites, the desorption rates as a function of the activation energies of desorption, and, finally, probability functions of the activation energies. The results are discussed in terms of coverage, Si/Al ratio, and accessibility.

• OSTI ID: 6879867
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 94:2; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603 -- Materials-- Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ACIDIZATION
ACTIVATION ENERGY
AMMONIA
DATA
DATA ANALYSIS
DESORPTION
ENERGY
EXPERIMENTAL DATA
HYDRIDES
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MASS SPECTROSCOPY
MATERIALS
MEASURING INSTRUMENTS
MEASURING METHODS
MINERALS
MORDENITE
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NUMERICAL DATA
SILICATE MINERALS
SPECTROSCOPY
ZEOLITES