A new approach to the study of the reactivity of solid-acid catalysts: The application of constant rate thermal analysis to the desorption and surface reaction of isopropylamine from NaY and HY zeolites

Elena A. Fesenko, Philip A. Barnes, Gareth M.B. Parkes, D. Robert Brown, Majid Naderi

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

A new and potentially valuable approach to the study of the acidity and reactivity of the surfaces of solid acid materials is described. The technique uses a combination of constant rate thermal analysis (CRTA) with the rate jump technique (CRTA-RJ) for temperature programmed desorption (TPD) and reaction (TPRx). CRTA, where the sample temperature is changed to force the rate of reaction to remain constant through a process, offers a number of advantages over conventional linear heating thermal methods by minimizing temperature and concentration gradients in the sample and reducing the effects of diffusion. CRTA and CRTA-RJ were applied to the TPD and TPRx of isopropylamine from NaY zeolite and its acidic form, HY. Activation energies of both the physical desorption of the amine and the surface-catalyzed Hoffman elimination reaction were calculated as a function of surface coverage and the advantages and limitations of the techniques are discussed. Comparisons are made with analogous TPD experiments using conventional linear heating methods. It is concluded that the TPRx approach reflects the reactivity of strong acidic catalytic sites directly and so usefully complements base adsorption microcalorimetry in characterizing acid solid catalysts.

LanguageEnglish
Pages6178-6185
Number of pages8
JournalJournal of Physical Chemistry B
Volume105
Issue number26
Early online date7 Jun 2001
DOIs
Publication statusPublished - 5 Jul 2001

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Zeolites
Surface reactions
zeolites
Thermoanalysis
surface reactions
Desorption
thermal analysis
reactivity
desorption
catalysts
Temperature programmed desorption
acids
Catalysts
Acids
Heating
Acidity
Amines
heating
temperature
Activation energy

Cite this

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abstract = "A new and potentially valuable approach to the study of the acidity and reactivity of the surfaces of solid acid materials is described. The technique uses a combination of constant rate thermal analysis (CRTA) with the rate jump technique (CRTA-RJ) for temperature programmed desorption (TPD) and reaction (TPRx). CRTA, where the sample temperature is changed to force the rate of reaction to remain constant through a process, offers a number of advantages over conventional linear heating thermal methods by minimizing temperature and concentration gradients in the sample and reducing the effects of diffusion. CRTA and CRTA-RJ were applied to the TPD and TPRx of isopropylamine from NaY zeolite and its acidic form, HY. Activation energies of both the physical desorption of the amine and the surface-catalyzed Hoffman elimination reaction were calculated as a function of surface coverage and the advantages and limitations of the techniques are discussed. Comparisons are made with analogous TPD experiments using conventional linear heating methods. It is concluded that the TPRx approach reflects the reactivity of strong acidic catalytic sites directly and so usefully complements base adsorption microcalorimetry in characterizing acid solid catalysts.",
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A new approach to the study of the reactivity of solid-acid catalysts : The application of constant rate thermal analysis to the desorption and surface reaction of isopropylamine from NaY and HY zeolites. / Fesenko, Elena A.; Barnes, Philip A.; Parkes, Gareth M.B.; Brown, D. Robert; Naderi, Majid.

In: Journal of Physical Chemistry B, Vol. 105, No. 26, 05.07.2001, p. 6178-6185.

Research output: Contribution to journalArticle

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