The poisoning effect of CO2 on a HY catalyst for the dehydration of 2-(2-hydroxyethyl)-pyridine (HEP) to 2-vinylpyridine (VP) has been investigated by FT-IR analysis in the presence and absence of pyridine. CO2 was found to adsorb on sites not occupied by pyridine, i.e. on weak basic sites accompanying the strongly acidic sites, characteristic of Y zeolites in the protonated form. When the basic sites are occupied by preadsorbed CO2, HEP dehydration cannot take place any more through the minor mechanism, involving a couple of acid-base sites, and the reaction proceeds only through the major mechanism, involving a carbocation intermediate, on Bronsted acid sites only.
CO2 poisoning effect on HY zeolite dehydration catalyst / L. Forni, E. Selli, E. Fumagalli, D. Mainini. - In: REACTION KINETICS AND CATALYSIS LETTERS. - ISSN 0133-1736. - 61:2(1997), pp. 267-273. [10.1007/BF02478382]
CO2 poisoning effect on HY zeolite dehydration catalyst
L. ForniPrimo
;E. SelliSecondo
;
1997
Abstract
The poisoning effect of CO2 on a HY catalyst for the dehydration of 2-(2-hydroxyethyl)-pyridine (HEP) to 2-vinylpyridine (VP) has been investigated by FT-IR analysis in the presence and absence of pyridine. CO2 was found to adsorb on sites not occupied by pyridine, i.e. on weak basic sites accompanying the strongly acidic sites, characteristic of Y zeolites in the protonated form. When the basic sites are occupied by preadsorbed CO2, HEP dehydration cannot take place any more through the minor mechanism, involving a couple of acid-base sites, and the reaction proceeds only through the major mechanism, involving a carbocation intermediate, on Bronsted acid sites only.
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