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Adsorbate-induced expansion of silicalite-1 crystals / Stephanie G. Sorenson in Industrial & engineering chemistry research, Vol. 47 N° 23 (Décembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9611–9616 Titre : Adsorbate-induced expansion of silicalite-1 crystals Type de document : texte imprimé Auteurs : Stephanie G. Sorenson, Auteur ; Joseph R. Smyth, Auteur ; Milan Kocirik, Auteur Année de publication : 2009 Article en page(s) : p. 9611–9616 Note générale : Chemistry engineering Langues : Anglais (eng) Mots-clés : Induced  expansion  Silicalite-1  crystals Résumé : Optical microscopy and XRD measurements show that silicalite-1 crystals expand when C4−C8 alkanes and i-butane adsorb in the MFI structure at room temperature. The c-direction linear expansion was 0.20−0.45%, and was measured with XRD and optical microscopy for 200 μm crystals. n-Pentane, n-hexane, and n-heptane had the maximum linear expansion of approximately 0.54% in the b-direction, and n-hexane and n-heptane had the maximum volume expansion of 1.2%. In contrast, benzene did not cause a significant change in the unit cell volume. The a-direction expanded least for the molecules studied except i-butane. n-Hexane expanded the silicalite-1 crystal more at 180 K than at room temperature. Crystal expansion due to n-alkane adsorption decreased the size of defects in a polycrystalline MFI membrane, and changes in the fluxes of i-octane through defects were measured by transient permeation. Loadings as low as 0.5 molecule/unit cell decreased the flux through defects at 358−473 K, but benzene had no effect. Higher loadings increased crystal expansion and decreased the defect size more. Crystal expansion was reversible. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800630g [article] Adsorbate-induced expansion of silicalite-1 crystals [texte imprimé] / Stephanie G. Sorenson, Auteur ; Joseph R. Smyth, Auteur ; Milan Kocirik, Auteur . - 2009 . - p. 9611–9616. Chemistry engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N° 23 (Décembre 2008) . - p. 9611–9616 Mots-clés : Induced  expansion  Silicalite-1  crystals Résumé : Optical microscopy and XRD measurements show that silicalite-1 crystals expand when C4−C8 alkanes and i-butane adsorb in the MFI structure at room temperature. The c-direction linear expansion was 0.20−0.45%, and was measured with XRD and optical microscopy for 200 μm crystals. n-Pentane, n-hexane, and n-heptane had the maximum linear expansion of approximately 0.54% in the b-direction, and n-hexane and n-heptane had the maximum volume expansion of 1.2%. In contrast, benzene did not cause a significant change in the unit cell volume. The a-direction expanded least for the molecules studied except i-butane. n-Hexane expanded the silicalite-1 crystal more at 180 K than at room temperature. Crystal expansion due to n-alkane adsorption decreased the size of defects in a polycrystalline MFI membrane, and changes in the fluxes of i-octane through defects were measured by transient permeation. Loadings as low as 0.5 molecule/unit cell decreased the flux through defects at 358−473 K, but benzene had no effect. Higher loadings increased crystal expansion and decreased the defect size more. Crystal expansion was reversible. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800630g