Proton proximity – New key parameter controlling adsorption, desorption and activity in propene oligomerization over H-ZSM-5 zeolites

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388955%3A_____%2F16%3A00464693" target="_blank" >RIV/61388955:_____/16:00464693 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.jcat.2016.09.025" target="_blank" >http://dx.doi.org/10.1016/j.jcat.2016.09.025</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jcat.2016.09.025" target="_blank" >10.1016/j.jcat.2016.09.025</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Proton proximity – New key parameter controlling adsorption, desorption and activity in propene oligomerization over H-ZSM-5 zeolites

Popis výsledku v původním jazyce

The proximity of protons (∼5 Å) derived from the distribution of Al atoms in the H-ZSM-5 framework has been shown to substantially affect the rate of propene oligomerization. Two sets of H-ZSM-5 zeolites (Si/Al 13–30) greatly differing in the occurrence of Al pairs (AlSiSiAl sequences in 6MRs) or distant Al atoms in the framework (both located prevailingly at the channel intersections) were synthesized to analyze the effect of the proton proximity. Propene adsorption and formation of oligomeric alkoxides is faster over distant isolated protons, while the close (5 Å) positive charges of proximate protons result in faster olefin(s) release from H-bonded propene and oligomeric alkoxides. As the steady-state TOF of propene oligomerization to C4–C9 olefins at 473–533 K over close protons exceeds 2–10 fold (with increasing Si/Al) those over isolated protons, the release of olefins from alkoxides is suggested to be an important reaction step. The distribution of framework Al atoms determining the mutual distances of protons represents a new parameter for evaluating rates of acid-catalyzed reactions and individual steps over H-zeolites.

Název v anglickém jazyce

Proton proximity – New key parameter controlling adsorption, desorption and activity in propene oligomerization over H-ZSM-5 zeolites

Popis výsledku anglicky

The proximity of protons (∼5 Å) derived from the distribution of Al atoms in the H-ZSM-5 framework has been shown to substantially affect the rate of propene oligomerization. Two sets of H-ZSM-5 zeolites (Si/Al 13–30) greatly differing in the occurrence of Al pairs (AlSiSiAl sequences in 6MRs) or distant Al atoms in the framework (both located prevailingly at the channel intersections) were synthesized to analyze the effect of the proton proximity. Propene adsorption and formation of oligomeric alkoxides is faster over distant isolated protons, while the close (5 Å) positive charges of proximate protons result in faster olefin(s) release from H-bonded propene and oligomeric alkoxides. As the steady-state TOF of propene oligomerization to C4–C9 olefins at 473–533 K over close protons exceeds 2–10 fold (with increasing Si/Al) those over isolated protons, the release of olefins from alkoxides is suggested to be an important reaction step. The distribution of framework Al atoms determining the mutual distances of protons represents a new parameter for evaluating rates of acid-catalyzed reactions and individual steps over H-zeolites.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

CF - Fyzikální chemie a teoretická chemie

OECD FORD obor

—

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Journal of Catalysis

ISSN

0021-9517

e-ISSN

—

Svazek periodika

344

Číslo periodika v rámci svazku

DEC 2016

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

16

Strana od-do

157-172

Kód UT WoS článku

000390182800016

EID výsledku v databázi Scopus

2-s2.0-84991660817