Surface equilibration in adsorption microcalorimetry of bases on H-USY

S. M. Babitz; B. A. Williams; M. A. Kuehne; H. H. Kung; Jeffrey T. Miller

doi:10.1016/s0040-6031(97)00436-x

Surface equilibration in adsorption microcalorimetry of bases on H-USY

S. M. Babitz, B. A. Williams, M. A. Kuehne, H. H. Kung^*, Jeffrey T. Miller

^*Corresponding author for this work

Chemical and Biological Engineering

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

21 Scopus citations

Abstract

It is commonly assumed that adsorbed basic probe molecules freely equilibrate with surface-acid sites in microcalorimetric experiments to determine the strength and distribution of the acid sites. The validity of this assumption was tested by comparing the differential heat of adsorption on H-USY as a function of surface coverage of CD₃NH₂, NH₃ and CD₃CN, which have widely different proton affinities, and by monitoring with FTIR the distribution of the adsorbed molecules between Brønsted- and Lewis-acid sites during adsorption and desorption. The results showed that full equilibration was achieved with the weakest base, CD₃CN, but not with the stronger bases, CD₃NH₂ or NH₃.

Original language	English (US)
Pages (from-to)	17-25
Number of pages	9
Journal	Thermochimica Acta
Volume	312
Issue number	1-2
DOIs	https://doi.org/10.1016/s0040-6031(97)00436-x
State	Published - Mar 23 1998

Keywords

Acid sites on HUSY
Adsorption of bases
Calorimetry
FTIR of adsorbed bases
HUSY acidity

ASJC Scopus subject areas

Instrumentation
Condensed Matter Physics
Physical and Theoretical Chemistry

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10.1016/s0040-6031(97)00436-x

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title = "Surface equilibration in adsorption microcalorimetry of bases on H-USY",

abstract = "It is commonly assumed that adsorbed basic probe molecules freely equilibrate with surface-acid sites in microcalorimetric experiments to determine the strength and distribution of the acid sites. The validity of this assumption was tested by comparing the differential heat of adsorption on H-USY as a function of surface coverage of CD3NH2, NH3 and CD3CN, which have widely different proton affinities, and by monitoring with FTIR the distribution of the adsorbed molecules between Br{\o}nsted- and Lewis-acid sites during adsorption and desorption. The results showed that full equilibration was achieved with the weakest base, CD3CN, but not with the stronger bases, CD3NH2 or NH3.",

keywords = "Acid sites on HUSY, Adsorption of bases, Calorimetry, FTIR of adsorbed bases, HUSY acidity",

author = "Babitz, {S. M.} and Williams, {B. A.} and Kuehne, {M. A.} and Kung, {H. H.} and Miller, {Jeffrey T.}",

note = "Funding Information: Financial support of this work by the National Science Foundation and in kind support by Amoco Corporation are gratefully acknowledged.",

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doi = "10.1016/s0040-6031(97)00436-x",

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T1 - Surface equilibration in adsorption microcalorimetry of bases on H-USY

AU - Babitz, S. M.

AU - Williams, B. A.

AU - Kuehne, M. A.

AU - Kung, H. H.

AU - Miller, Jeffrey T.

N1 - Funding Information: Financial support of this work by the National Science Foundation and in kind support by Amoco Corporation are gratefully acknowledged.

PY - 1998/3/23

Y1 - 1998/3/23

N2 - It is commonly assumed that adsorbed basic probe molecules freely equilibrate with surface-acid sites in microcalorimetric experiments to determine the strength and distribution of the acid sites. The validity of this assumption was tested by comparing the differential heat of adsorption on H-USY as a function of surface coverage of CD3NH2, NH3 and CD3CN, which have widely different proton affinities, and by monitoring with FTIR the distribution of the adsorbed molecules between Brønsted- and Lewis-acid sites during adsorption and desorption. The results showed that full equilibration was achieved with the weakest base, CD3CN, but not with the stronger bases, CD3NH2 or NH3.

AB - It is commonly assumed that adsorbed basic probe molecules freely equilibrate with surface-acid sites in microcalorimetric experiments to determine the strength and distribution of the acid sites. The validity of this assumption was tested by comparing the differential heat of adsorption on H-USY as a function of surface coverage of CD3NH2, NH3 and CD3CN, which have widely different proton affinities, and by monitoring with FTIR the distribution of the adsorbed molecules between Brønsted- and Lewis-acid sites during adsorption and desorption. The results showed that full equilibration was achieved with the weakest base, CD3CN, but not with the stronger bases, CD3NH2 or NH3.

KW - Acid sites on HUSY

KW - Adsorption of bases

KW - Calorimetry

KW - FTIR of adsorbed bases

KW - HUSY acidity

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IS - 1-2

ER -

Surface equilibration in adsorption microcalorimetry of bases on H-USY

Abstract

Keywords

ASJC Scopus subject areas

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