T. Deconinck

How zeolitic acid strength and composition alter the reactivity of alkenes and aromatics towards methanol

M.W. Erichsen, K. De Wispelaere, K. Hemelsoet, S.L. Moors, T. Deconinck, M. Waroquier, S. Svelle, V. Van Speybroeck, U. Olsbye
Journal of Catalysis
328, 186-196
2015
A1

Abstract 

This work encompasses a combined experimental and theoretical assessment of how zeolitic acid strength and composition affects acid-catalysed methylation reactions. Overall, higher methylation rates were observed over the material with higher acid strength. Co-reactions of methanol with benzene at 250 degrees C over the two isostructural AFI materials H-SSZ-24 and H-SAPO-5 revealed large differences in selectivity. While the stronger acidic H-SSZ-24 mainly produced toluene and polymethylbenzenes, high yields of C4+ aliphatics were observed over H-SAPO-5. These results strongly suggest that alkene methylation was preferred over H-SAPO-5 even at very low conversion during methanol/benzene co-reactions. Furthermore, a comparison of benzene and propene methylation at 350-400 degrees C revealed a significantly faster rate of benzene than propene methylation in H-SSZ-24, whereas the rates of benzene and propene methylation were similar in H-SAPO-5. The observed difference in reactivity of the two hydrocarbons in both catalysts could be understood by careful analysis of various molecular dynamics simulations of the co-adsorbed complexes. The probability to form protonated methanol was, as expected, higher in the more acidic material. However, in H-SSZ-24, the probability for methanol protonation was higher when co-adsorbed with benzene than when co-adsorbed with propene, while the same was not observed in H-SAPO-5. Furthermore, it was found that benzene and methanol are more likely to form a reactive co-adsorbed complex in H-SSZ-24 compared to propene and methanol, while the opposite was observed for H-SAPO-5. This work shows that molecular dynamics simulations provide insights into the adsorption behaviour of guest molecules in large pore AFI materials. The obtained insights correlate with the experimentally observed reactivities. (C) 2015 Elsevier Inc. All rights reserved.

Open Access version available at UGent repository

Combined Theoretical and Experimental Study on the Influence of Zeolitic Acid Strength on the Methanol Conversion Process

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Talk

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ZMPC2015
Sapporo, Japan
Sunday, 28 June, 2015 to Thursday, 2 July, 2015

Combined theoretical and experimental study on the influence of catalyst acid strength on the zeolite-catalyzed methanol conversion process

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DZA14 meeting (Dutch Zeolite Association)
Gent, Belgium
Tuesday, 7 October, 2014

The influence of catalyst acid strength on reactions relevant for Methanol To Hydrocarbons (MTH) catalysis

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16th Nordic Symposium on Catalysis (NSC2014)
Oslo, Norway
Sunday, 15 June, 2014 to Tuesday, 17 June, 2014

Dynamic ab initio study towards new hydrocarbon pool cycles for the MTO-conversion in H-SAPO-5

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Poster

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XVth Netherlands' Catalysis and Chemistry Conference (NCCC XV)
Noordwijkerhout, The Netherlands
Monday, 10 March, 2014 to Wednesday, 12 March, 2014
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