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The acidity of trivalent cation-exchanged montmorillonite. II. Desorption of mono- and di-substituted pyridines

Published online by Cambridge University Press:  09 July 2018

C. Breen
C. Breen*
Affiliation:
Chemistry Department, Sheffield City Polytechnic, Pond Street, Sheffield, S1 1WB, UK
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Abstract

Temperature programmed desorption (TPD) and IR spectroscopy were used to examine the desorption of pyridine, 2-methyl-, 4-methyl- and 2,6-dimethylpyridine from Al3+- and Cr3+-montmorillonite. Pyridine desorbed from Lewis sites at 150°C and from Bronsted sites at 340°C. 4-methylpyridine desorbed from Lewis and Bronsted centres at 210°C and 410°C respectively, some 60°C higher than pyridine due to its higher basicity. Conversely, the 2-methyl- and 2,6-dimethylpyridine, which are sterically hampered with respect to their coordination to Lewis centres, desorbed from these sites near 100°C, but due to their greater basicity desorbed from Bronsted sites at higher temperatures. These interpretations were confirmed by IR spectroscopy.

Type
Research Article
Information
Clay Minerals , Volume 23 , Issue 3 , September 1988 , pp. 323 - 328
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1988

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