title: Confined But-2-ene Catalytic Isomerization Inside H-ZSM-5 Models: A DFT Study.
abstract: The isomerization of cis-but-2-ene to trans-but-2-ene within a 22T H-ZSM-5 zeolite model, also in the presence of two adsorbed Pd atoms, has been studied by DFT calculations. The results obtained allow us to state that the cis/trans but-2-ene isomerization can easily proceed inside unsupported zeolite cavities. In this case, differently than in the gas phase reaction, the trans-but-2-ene is less stable than the cis-but-2-ene, when adsorbed on the zeolite inner surface. Excluding the adsorption-desorption steps, the isomerization process involves two intermediates and three transition states, whose energy content is always very low with respect to that of reagents and intermediate species. The reaction is in principle allowed also in the presence of two Pd atoms embedded inside the zeolite cavity. However, strong H-Pd interactions seem to cause higher activation energies along the formation of the involved intermediates and transition states. To evaluate the confining effects of the zeolite room on the cis/trans isomerization process, the latter has been also analyzed on protonated (Pd2H(+)) and unprotonated (Pd2) bare palladium fragments at different multiplicity states. The but-2-ene adsorption on the considered systems and the mutual influence occurring between the metal atoms and the hydrogen acidic sites at different multiplicity states have also been taken into consideration.
authors.affiliation: Dipartimento di Chimica Inorganica e Analitica "S. Cannizzaro" dell'Università, viale delle Scienze Ed. 17, I-90128 Palermo, Italy, and Laboratory of Industrial Chemistry, Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FIN-20500 Åbo/Turku, Finland.
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Barone
authors.affiliation: Dipartimento di Chimica Inorganica e Analitica "S. Cannizzaro" dell'Università, viale delle Scienze Ed. 17, I-90128 Palermo, Italy, and Laboratory of Industrial Chemistry, Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FIN-20500 Åbo/Turku, Finland.
authors.forename: Nerina
authors.initials: N
authors.lastname: Armata
authors.affiliation: Dipartimento di Chimica Inorganica e Analitica "S. Cannizzaro" dell'Università, viale delle Scienze Ed. 17, I-90128 Palermo, Italy, and Laboratory of Industrial Chemistry, Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FIN-20500 Åbo/Turku, Finland.
authors.forename: Antonio
authors.initials: A
authors.lastname: Prestianni
authors.affiliation: Dipartimento di Chimica Inorganica e Analitica "S. Cannizzaro" dell'Università, viale delle Scienze Ed. 17, I-90128 Palermo, Italy, and Laboratory of Industrial Chemistry, Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FIN-20500 Åbo/Turku, Finland.
authors.forename: Teresa
authors.initials: T
authors.lastname: Rubino
authors.affiliation: Dipartimento di Chimica Inorganica e Analitica "S. Cannizzaro" dell'Università, viale delle Scienze Ed. 17, I-90128 Palermo, Italy, and Laboratory of Industrial Chemistry, Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FIN-20500 Åbo/Turku, Finland.
authors.forename: Dario
authors.initials: D
authors.lastname: Duca
authors.affiliation: Dipartimento di Chimica Inorganica e Analitica "S. Cannizzaro" dell'Università, viale delle Scienze Ed. 17, I-90128 Palermo, Italy, and Laboratory of Industrial Chemistry, Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FIN-20500 Åbo/Turku, Finland.
authors.forename: Dmitry Yu
authors.initials: DY
authors.lastname: Murzin