Effect of framework Al content on HY acidity and cracking activity

M. A. Kuehne; S. M. Babitz; H. H. Kung; J. T. Miller

doi:10.1016/S0926-860X(97)00262-7

Effect of framework Al content on HY acidity and cracking activity

M. A. Kuehne, S. M. Babitz, H. H. Kung^*, J. T. Miller

^*Corresponding author for this work

CCSS - Center for Catalysis and Surface Science

Research output: Contribution to journal › Article › peer-review

47 Scopus citations

Abstract

The acidic properties and 2-methylpentane cracking turnover frequencies (TOFs) were compared for HY and two dealuminated HY zeolites with similar levels of framework Al: HDY that was dealuminated by ammonium hexafluorosilicate, and a (H,NH₄)-USY zeolite that was dealuminated by steam. The acid strength distributions were determined by microcalorimetry of NH₃ adsorption, and the types of acid sites by FTIR spectroscopy. All zeolites possessed Brønsted acid sites with very few Lewis acid sites. The differential heat of adsorption of NH₃ on these zeolites was nearly constant: about 120 kJ/mol for HY and HDY and approximately 7 kJ/mol higher for the (H,NH₄)-USY. The cracking TOF for HDY was five times larger than HY, while the TOF of (H,NH₄)-USY was 80 times higher. These results suggest that the cracking activity may be affected by other factors in addition to acid strength.

Original language	English (US)
Pages (from-to)	293-299
Number of pages	7
Journal	Applied Catalysis A: General
Volume	166
Issue number	2
DOIs	https://doi.org/10.1016/S0926-860X(97)00262-7
State	Published - Jan 8 1998

Keywords

Cracking, effect of acidity and AI content
USY zeolite, acidity
USY zeolite, effect of AI content
USY zeolite, hydrocarbon cracking

ASJC Scopus subject areas

Catalysis
Process Chemistry and Technology

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title = "Effect of framework Al content on HY acidity and cracking activity",

abstract = "The acidic properties and 2-methylpentane cracking turnover frequencies (TOFs) were compared for HY and two dealuminated HY zeolites with similar levels of framework Al: HDY that was dealuminated by ammonium hexafluorosilicate, and a (H,NH4)-USY zeolite that was dealuminated by steam. The acid strength distributions were determined by microcalorimetry of NH3 adsorption, and the types of acid sites by FTIR spectroscopy. All zeolites possessed Br{\o}nsted acid sites with very few Lewis acid sites. The differential heat of adsorption of NH3 on these zeolites was nearly constant: about 120 kJ/mol for HY and HDY and approximately 7 kJ/mol higher for the (H,NH4)-USY. The cracking TOF for HDY was five times larger than HY, while the TOF of (H,NH4)-USY was 80 times higher. These results suggest that the cracking activity may be affected by other factors in addition to acid strength.",

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AU - Kuehne, M. A.

AU - Babitz, S. M.

AU - Kung, H. H.

AU - Miller, J. T.

PY - 1998/1/8

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N2 - The acidic properties and 2-methylpentane cracking turnover frequencies (TOFs) were compared for HY and two dealuminated HY zeolites with similar levels of framework Al: HDY that was dealuminated by ammonium hexafluorosilicate, and a (H,NH4)-USY zeolite that was dealuminated by steam. The acid strength distributions were determined by microcalorimetry of NH3 adsorption, and the types of acid sites by FTIR spectroscopy. All zeolites possessed Brønsted acid sites with very few Lewis acid sites. The differential heat of adsorption of NH3 on these zeolites was nearly constant: about 120 kJ/mol for HY and HDY and approximately 7 kJ/mol higher for the (H,NH4)-USY. The cracking TOF for HDY was five times larger than HY, while the TOF of (H,NH4)-USY was 80 times higher. These results suggest that the cracking activity may be affected by other factors in addition to acid strength.

AB - The acidic properties and 2-methylpentane cracking turnover frequencies (TOFs) were compared for HY and two dealuminated HY zeolites with similar levels of framework Al: HDY that was dealuminated by ammonium hexafluorosilicate, and a (H,NH4)-USY zeolite that was dealuminated by steam. The acid strength distributions were determined by microcalorimetry of NH3 adsorption, and the types of acid sites by FTIR spectroscopy. All zeolites possessed Brønsted acid sites with very few Lewis acid sites. The differential heat of adsorption of NH3 on these zeolites was nearly constant: about 120 kJ/mol for HY and HDY and approximately 7 kJ/mol higher for the (H,NH4)-USY. The cracking TOF for HDY was five times larger than HY, while the TOF of (H,NH4)-USY was 80 times higher. These results suggest that the cracking activity may be affected by other factors in addition to acid strength.

KW - Cracking, effect of acidity and AI content

KW - USY zeolite, acidity

KW - USY zeolite, effect of AI content

KW - USY zeolite, hydrocarbon cracking

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Effect of framework Al content on HY acidity and cracking activity

Abstract

Keywords

ASJC Scopus subject areas

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