Sulfonated periodic-mesoporous-organosilicas column for selective separation of C 2 H 2 /CH 4 mixtures

Use of Periodic Mesoporous Organosilica-Benzene Adsorbent for CO2 Capture to Reduce the Greenhouse Effect

The CO2 adsorption of a phenylene-bridged ordered mesoporous organosilica (PMO-benzene) was analyzed. The maximum capture capacity was 638.2 mg·g-1 (0 °C and 34 atm). Approximately 0.43 g would be enough to reduce the amount of atmospheric CO2 in 1 m3 to pre-industrial levels. The CO2 adsorption data were analyzed using several isotherm models, including Langmuir, Freundlich, Sips, Toth, Dubinin-Radushkevich, and Temkin models. This study confirmed the capability of this material for use in reversible CO2 capture with a minimal loss of capacity (around 1%) after 10 capture cycles. Various techniques were employed to characterize this material. The findings from this study can help mitigate the greenhouse effect caused by CO2.

Synthesis of (E)-2-(1H-tetrazole-5-yl)-3-phenylacrylenenitrile derivatives catalyzed by new ZnO nanoparticles embedded in a thermally stable magnetic periodic mesoporous organosilica under green conditions

ZnO nanoparticles embedded in a magnetic isocyanurate-based periodic mesoporous organosilica (Fe3O4@PMO-ICS-ZnO) were prepared through a modified environmentally-benign procedure for the first time and properly characterized by appropriate spectroscopic and analytical methods or techniques used for mesoporous materials. The new thermally stable Fe3O4@PMO-ICS-ZnO nanomaterial with proper active sites and surface area as well as uniform particle size was investigated for the synthesis of medicinally important tetrazole derivatives through cascade condensation and concerted 1,3-cycloaddition reactions as a representative of the Click Chemistry concept. The desired 5-substituted-1H-tetrazole derivatives were smoothly prepared in high to quantitative yields and good purity in EtOH under reflux conditions. Low catalyst loading, short reaction time and the use of green solvents such as EtOH and water instead of carcinogenic DMF as well as easy separation and recyclability of the catalyst for at least five consecutive runs without significant loss of its activity are notable advantages of this new protocol compared to other recent introduced procedures.

Novel magnetic propylsulfonic acid-anchored isocyanurate-based periodic mesoporous organosilica (Iron oxide@PMO-ICS-PrSO3H) as a highly efficient and reusable nanoreactor for the sustainable synthesis of imidazopyrimidine derivatives

In this study, preparation and characterization of a new magnetic propylsulfonic acid-anchored isocyanurate bridging periodic mesoporous organosilica (Iron oxide@PMO-ICS-PrSO3H) is described. The iron oxide@PMO-ICS-PrSO3H nanomaterials were characterized by Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy and field emission scanning electron microscopy as well as thermogravimetric analysis, N2 adsorption-desorption isotherms and vibrating sample magnetometer techniques. Indeed, the new obtained materials are the first example of the magnetic thermally stable isocyanurate-based mesoporous organosilica solid acid. Furthermore, the catalytic activity of the Iron oxide@PMO-ICS-PrSO3H nanomaterials, as a novel and highly efficient recoverable nanoreactor, was investigated for the sustainable heteroannulation synthesis of imidazopyrimidine derivatives through the Traube-Schwarz multicomponent reaction of 2-aminobenzoimidazole, C‒H acids and diverse aromatic aldehydes. The advantages of this green protocol are low catalyst loading, high to quantitative yields, short reaction times and the catalyst recyclability for at least four consecutive runs.

Functionalized Periodic Mesoporous Organosilicas: Tunable Hydrophobic Solid Acids for Biomass Conversion

The catalytic deoxygenation of bio-based feedstocks to fuels and chemicals presents new challenges to the catalytic scientist, with many transformations either performed in or liberating water as a byproduct during reaction. The design of catalysts with tunable hydrophobicity to aid product and reactant adsorption or desorption, respectively, is vital for processes including (trans)esterification and condensation reactions employed in sustainable biodiesel production and bio-oil upgrading processes. Increasing surface hydrophobicity of catalyst materials offers a means to displace water from the catalyst active site, and minimizes potential deactivation or hydrolysis side reactions. Hybrid organic⁻inorganic porous solids offer exciting opportunities to tune surface polarity and hydrophobicity, as well as critical parameters in controlling adsorption, reactant activation, and product selectivity in liquid and vapor phase catalysis. Here, we review advances in the synthesis and application of sulfonic-acid-functionalized periodic mesoporous organosilicas (PMO) as tunable hydrophobic solid acid catalysts in reactions relevant to biorefining and biofuel production.

Additive-Induced Supramolecular Isomerism and Enhancement of Robustness in Co(II)-Based MOFs for Efficiently Trapping Acetylene from Acetylene-Containing Mixtures

Although supramolecular isomerism in metal-organic frameworks (MOFs) would offer a favorable platform for in-depth exploring their structure-property relationship, the design and synthesis of the isomers are still rather a challenging aspect of crystal engineering. Here, a pair of supramolecular isomers of Co(II)-based MOFs (FJU-88 and FJU-89) can be directionally fabricated by rational tuning the additives. In spite of the fact that the isomers have the similar Co₃ secondary building units and organic linkers, they adopt distinct networks with acs and snw topologies, respectively, which derive from the conformational flexibility of the organic ligands. It is noteworthy that the porous structure of FJU-88 would be collapsed after removal of the solvent from the pores. But FJU-89a shows permanent porosity accompanied with unusual hierarchical micro- and mesopores and superior gas selective adsorption performance. In addition, FJU-89a can efficiently trap C₂H₂ from C₂H₂/CO₂ and C₂H₂/CH₄ mixture gases through fixed-bed dynamic breakthrough experiments.

Flue gas adsorption on periodic mesoporous phenylene-silica: a DFT approach

Periodic mesoporous organosilicas (PMOs) were suggested as potential adsorbents for CO2/CH4 separation because of their large affinities towards CO2 and low interaction with CH4. Herewith, we present a comprehensive computational study on the binding properties of flue gas species with the pore walls of periodic mesoporous phenylene-silica (Ph-PMO) for understanding the possible impact of other gaseous species in the CO2/CH4 separation. The calculations considered three exchange-correlation functionals (PBE, PBE-D2 and M06-2X) based on the density functional theory and the walls of the periodic mesoporous phenylene-silica were modelled within the cluster model approach. The components of the flue gas considered were the diatomic CO, H2, N2, O2 and NO molecules, the triatomic CO2, H2O, H2S and SO2 species, the tetratomic SO3 and NH3 gases and the pentatomic CH4 molecule. The calculated data demonstrate that the presence of H2O, SO2, NH3, H2S and SO3 is a significant threat to CO2 capture by Ph-PMO and suggest that the Ph-PMO material would present high selectivity for CO2 over CH4, CO, H2 or N2 adsorption. The adsorption behaviour of flue gas components in Ph-PMO can be directly related to the experimental proton affinities, basicities or even the polarizabilities of the gaseous molecules.