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Organic – inorganic hybrid silica membranes with controlled silica network size for propylene / propane separation / Masakoto Kanezashi in Industrial & engineering chemistry research, Vol. 51 N° 2 (Janvier 2012) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 51 N° 2 (Janvier 2012) . - pp. 944–953 Titre : Organic – inorganic hybrid silica membranes with controlled silica network size for propylene / propane separation Type de document : texte imprimé Auteurs : Masakoto Kanezashi, Auteur ; Mitsuki Kawano, Auteur ; Tomohisa Yoshioka, Auteur Année de publication : 2012 Article en page(s) : pp. 944–953 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Hybrid  silica  membranes Résumé : Bis(triethoxysilyl)methane (BTESM), which consists of Si–C–Si bonds, was used as a membrane precursor to control the size of amorphous silica networks. The single gas permeation characteristics of hybrid silica membranes were examined to determine the effect of silica precursors on amorphous networks. Pore size distribution, as determined by single gas permeation, suggested that average pore size was in the following order: bis(triethoxysilyl)ethane (BTESE)-derived silica > BTESM-derived silica > tetraethoxysilane (TEOS)-derived silica, due to differences in the minimum units of the silica precursor. The high C3H6/C3H8 separation performance of BTESM-derived silica membranes in a wide temperature range (50–200 °C) can be due to the control of silica network size by the “spacer” method using a Si–C–Si unit. For example, a BTESM-derived silica membrane showed a high C3H6 permeance of 6.32 × 10–7 mol m–2 s–1 Pa–1 with a C3H6/C3H8 permeance ratio of 8.8 at 50 °C. The order of C3H6 and C3H8 permeances of BTESM-derived silica membranes was C3H6 > C3H8, independent of the number of sol coats and temperature (50–200 °C), although the kinetic diameter of C3H6 (dk = 0.45 nm) was reported to be larger than that of C3H8 (dk = 0.43 nm). For permeation of hydrocarbons through amorphous silica membranes, it is suggested that the kinetic diameter, which is a minimum equilibrium cross-sectional diameter, is not applicable for effective molecular size, probably because diffusivity depends not only on the minimum cross section but also on molecular length. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201606k [article] Organic – inorganic hybrid silica membranes with controlled silica network size for propylene / propane separation [texte imprimé] / Masakoto Kanezashi, Auteur ; Mitsuki Kawano, Auteur ; Tomohisa Yoshioka, Auteur . - 2012 . - pp. 944–953. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 2 (Janvier 2012) . - pp. 944–953 Mots-clés : Hybrid  silica  membranes Résumé : Bis(triethoxysilyl)methane (BTESM), which consists of Si–C–Si bonds, was used as a membrane precursor to control the size of amorphous silica networks. The single gas permeation characteristics of hybrid silica membranes were examined to determine the effect of silica precursors on amorphous networks. Pore size distribution, as determined by single gas permeation, suggested that average pore size was in the following order: bis(triethoxysilyl)ethane (BTESE)-derived silica > BTESM-derived silica > tetraethoxysilane (TEOS)-derived silica, due to differences in the minimum units of the silica precursor. The high C3H6/C3H8 separation performance of BTESM-derived silica membranes in a wide temperature range (50–200 °C) can be due to the control of silica network size by the “spacer” method using a Si–C–Si unit. For example, a BTESM-derived silica membrane showed a high C3H6 permeance of 6.32 × 10–7 mol m–2 s–1 Pa–1 with a C3H6/C3H8 permeance ratio of 8.8 at 50 °C. The order of C3H6 and C3H8 permeances of BTESM-derived silica membranes was C3H6 > C3H8, independent of the number of sol coats and temperature (50–200 °C), although the kinetic diameter of C3H6 (dk = 0.45 nm) was reported to be larger than that of C3H8 (dk = 0.43 nm). For permeation of hydrocarbons through amorphous silica membranes, it is suggested that the kinetic diameter, which is a minimum equilibrium cross-sectional diameter, is not applicable for effective molecular size, probably because diffusivity depends not only on the minimum cross section but also on molecular length. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie201606k