UV−Vis Spectroscopy of Iodine Adsorbed on Alkali-Metal-Modified Zeolite Catalysts for Addition of Carbon Dioxide to Ethylene Oxide

Autor:	Eric J. Doskocil, Shailendra V. Bordawekar, Brian G. Kaye, Robert J. Davis
Rok vydání:	1999
Předmět:	Ethylene oxide Absorption spectroscopy Chemistry Inorganic chemistry Oxide chemistry.chemical_element Alkali metal Iodine Surfaces Coatings and Films Catalysis chemistry.chemical_compound Adsorption Ultraviolet visible spectroscopy Materials Chemistry Physical and Theoretical Chemistry
Zdroj:	The Journal of Physical Chemistry B. 103:6277-6282
ISSN:	1520-5207 1520-6106
DOI:	10.1021/jp991091t
Popis:	The basicity of alkali-metal-exchanged (Na, K, Cs) zeolites X and Y was probed by UV−vis diffuse reflectance spectroscopy of adsorbed iodine. The observed blue shift in the visible absorption spectrum of adsorbed iodine, compared to gaseous iodine, correlated well with the negative charge on the framework oxygen atoms calculated from the Sanderson electronegativity equalization principle. The blue shifts associated with iodine adsorbed on classical catalytic supports like silica, alumina, and magnesia suggest that the iodine adsorption technique for probing basicity is applicable to a wide variety of solids. Iodine was also adsorbed on X and Y zeolites containing occluded cesium oxide formed by decomposition of impregnated cesium acetate. However, the iodine appeared to irreversibly react on these strongly basic samples, possibly forming an adsorbed triiodide ion. As a complement to the adsorption studies, the activity of alkali-metal-containing zeolites for the base-catalyzed formation of ethylene carbon...
Databáze:	OpenAIRE
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