Toluene disproportionation and coking on zeolites Y modified with Lewis-connected InO+ acid sites
| Autor: | Gabriella Pál-Borbély, V. Mavrodinova, R.M. Mihályi, Ch. Minchev, Margarita Popova |
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| Rok vydání: | 2004 |
| Předmět: |
chemistry.chemical_classification
Process Chemistry and Technology Inorganic chemistry Disproportionation Electron acceptor Heterogeneous catalysis Medicinal chemistry Toluene Catalysis chemistry.chemical_compound chemistry Lewis acids and bases Physical and Theoretical Chemistry Brønsted–Lowry acid–base theory Zeolite |
| Zdroj: | Journal of Molecular Catalysis A: Chemical. 220:239-246 |
| ISSN: | 1381-1169 |
| DOI: | 10.1016/j.molcata.2004.06.005 |
| Popis: | The effect of introduction of Lewis acid sites on the reactions of toluene transformation and catalysts coking has been studied over parent (Si/Al = 2.5) and dealuminated (Si/Al = 3.7) Y zeolites modified with Lewis connected InO+ cationic acid sites. The catalysts with prevalent amount of Bronsted acid sites (less than 40% of protons exchanged by InO+) possess the typical for the proton directed reaction of methyl transfer upon toluene disproportionation long period of activation, the longer the higher the concentration of bridging protons. In contrast, at predominant Lewis sites concentration, the activation period disappear, an enhanced initial activity is observed, followed by deactivation on the expense of a rapid process of accumulation of strongly held reaction products and intermediates. Their further condensation leads to catalysts aging, the faster the higher the concentration of electron acceptor Lewis acid sites. A relation has been found between the initially accelerated processes of alkyl transfer and the reinforced formation of carbonaceous deposits over the In-modified catalysts. |
| Databáze: | OpenAIRE |
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