| Autor: |
Boroun S; Department of Chemical Engineering, Université Laval, 1065 Avenue de la Médecine, Québec, Québec G1 V 0A6, Canada., Sahraei AA; Department of Chemical Engineering, Université Laval, 1065 Avenue de la Médecine, Québec, Québec G1 V 0A6, Canada., Mokarizadeh AH; Department of Polymer Science, University of Akron, Akron, Ohio 44325, United States., Alamdari H; Department of Mining, Metallurgical and Materials Engineering, Université Laval, 1065 Avenue de la Médecine, Québec, Québec City G1 V 0A6, Canada., Fontaine FG; Department of Chemistry, Centre de de Catalyse et Chimie Verte (C3 V), Université Laval, 1045 Avenue de la Médecine, Québec, Québec G1 V 0A6, Canada., Larachi F; Department of Chemical Engineering, Université Laval, 1065 Avenue de la Médecine, Québec, Québec G1 V 0A6, Canada. |
| Abstrakt: |
Gas solubility can go beyond classical bulk-liquid Henry's law saturation under the nanoconfinement of a liquid phase. This concept establishes the foundation of the current study for developing a novel catalytic system for transformation of carbon dioxide to cyclic carbonates at mild conditions with major emphasis on application for CO 2 capture and utilization. A series of mesoporous silica-based supports of various pore sizes and shapes grafted with a quaternary ammonium salt is synthesized and characterized. CO 2 sorption in styrene oxide, either in bulk or nanoconfined state, as well as catalytic reactivity for CO 2 transformation into styrene carbonate, are experimentally evaluated. The family of mesoporous catalysts with aligned cylindrical pores (MCM-41 and SBA-15) with pore sizes ranging from 3.5 to 9 nm exhibit enhanced sorption of CO 2 in nanoconfined styrene oxide with maximum sorption capacity taking place in MCM-41 with the smallest pore size. The catalysts with interconnected cylindrical pores (KIT-6) with pore sizes ranging from 4.5 to 8.7 nm showed CO 2 solubilities almost equal to the bulk solubility of styrene oxide. Monte Carlo simulations revealed that the oversolubility in styrene oxide confined complex is directly related to the density of adsorbed solvent in the nanopore, which is less than its bulk density. Catalytic reactivities correlate with CO 2 sorption enhancement, showing higher turnover frequencies for catalysts having higher CO 2 sorption capacity. The turnover frequency is increased by a factor of 7.5 for grafted MCM-41 with the smallest pore size with nanoconfined styrene oxide in comparison to the homogeneous reaction implemented in bulk. |
