Characterization of H, Na-Y using amine desorption

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

DOI:https://doi.org/10.1006/jcat.1993.1323· OSTI ID:5042412

Biaglow, A I; Parrillo, D J; Gorte, R J ^[1]

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1. Univ. of Pennsylvania, Philadelphia, PA (United States)

The authors have examined series of partially ion-exchanged H, Na-Y zeolites using temperature programmed desorption (TPD) and thermogravimetric analysis (TGA) of isopropylamine and n-propylamine in order to examine the acid sites in H-Y zeolites as a function of Na poisoning. Both amines desorbed from Na-Y, unreacted, below 500 K; however, samples containing protonic sites exhibited two additional desorption features. First, unreacted amine molecules were observed leaving the samples between [approximately] 500 and 600 K. Second, reaction features appeared which were observed as the simultaneous desorption of propene and ammonia between 575 and 650 K for isopropylamine and between 625 and 700 K for n-propylamine. For a given sample, the number of both isopropylene and n-propylamine molecules which desorbed in both features was identical. Furthermore, the number of molecules desorbing from the two high-temperature features was found to be equal to the number of protonic sites for the entire series, which indicates that both desorption features are associated with protonic sites. This finding was confirmed by infrared spectroscopy, which also demonstrated that the unreacting desorption feature was associated with the low-frequency, hydroxyl stretch at 3540 cm[sup [minus]1] and that the reacting amine molecules was adsorbed at the high-frequency, hydroxyl stretch near 3640 cm[sup [minus]1]. The implications of these results for understanding the use of TPD-TGA of amines for the characterization of acidity is discussed. 30 refs., 9 figs., 2 tabs.

• OSTI ID: 5042412
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 144:1; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ABSORPTION SPECTROSCOPY
AMINES
CHEMICAL ANALYSIS
DESORPTION
GRAVIMETRIC ANALYSIS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
MINERALS
ORGANIC COMPOUNDS
QUANTITATIVE CHEMICAL ANALYSIS
SILICATE MINERALS
SORPTION
SORPTIVE PROPERTIES
SPECTROSCOPY
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
ZEOLITES