The high-pressure behavior of six synthetic zeolites with the MFI topology, characterized by different chemical composition (framework-Si partially replaced by Al or B and counterbalanced by Na or H as extra-framework cations), has been investigated by in-situ powder synchrotron X-ray diffraction using silicone-oil and methanol as hydrostatic pressure-transmitting fluids. For each sample, the compressibility in silicone-oil has been found to be considerably higher than that in methanol. This difference in terms of bulk elasticity is due to the adsorption of methanol already at P < 0.1 GPa, with different magnitudes as a function of the sample crystal-chemistry. The high number of experimental pressure points allowed an accurate determination of the monoclinic-to-orthorhombic phase transition (MOPT), detected between 0.3 and 0.7 GPa in the samples compressed in silicone-oil, whereas the orthorhombic Pnma polymorph has been found to be stable already at ∼ 0.1 GPa in four samples compressed in methanol. This suggests that the adsorption of methanol may increase the P-stability range of the orthorhombic Pnma phase. A comparative analysis of the effect of pressure on the methanol adsorption by MFI-zeolites with different chemical composition is provided, which offers potentially useful information on their application as catalysts in the methanol-to-olefins conversion processes and in industrial high-pressure processes.
The elastic behavior of zeolitic frameworks : The case of MFI type zeolite under high-pressure methanol intrusion / D. Comboni, F. Pagliaro, P. Lotti, G.D. Gatta, M. Merlini, S. Milani, M. Migliori, G. Giordano, E. Catizzone, I.E. Collings, M. Hanfland. - In: CATALYSIS TODAY. - ISSN 0920-5861. - 345(2020 Apr 01), pp. 88-96.
|Titolo:||The elastic behavior of zeolitic frameworks : The case of MFI type zeolite under high-pressure methanol intrusion|
COMBONI, DAVIDE (Primo) [Writing – Original Draft Preparation] (Corresponding)
PAGLIARO, FRANCESCO (Secondo) [Writing – Review & Editing]
GATTA, GIACOMO DIEGO [Conceptualization]
|Parole Chiave:||In-situ characterization; Methanol adsorption; MFI-topology; MOPT; Olefins; Pressure; Synchrotron X-ray diffraction|
|Settore Scientifico Disciplinare:||Settore GEO/09 - Georisorse Miner.Appl.Mineral.-Petrogr.per l'amb.e i Beni Cul|
|Data di pubblicazione:||1-apr-2020|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.cattod.2019.10.007|
|Appare nelle tipologie:||01 - Articolo su periodico|