0000000000166438
AUTHOR
Leonarda Francesca Liotta
Materiali ibridi a base di POSS-Imidazolio per la conversione della CO2 in carbonati ciclici
Lo sviluppo di catalizzatori per i processi di conversione della CO2 è una tematica che sta rivestendo un ruolo di rilevante importanza in ambito non soltanto accademico ma anche industriale grazie alla possibilità di trasformare un rifiuto, quale il diossido di carbonio, in una vasta gamma di prodotti. Nel presente lavoro, nuovi materiali ibridi costituiti da silsesquiossani poliedrici oligomerici (POSS) supportati su silice e funzionalizzati con sali di imidazolio sono stati progettati per la fissazione della CO2. 1 Tutti i solidi sono stati ampiamente caratterizzati e testati per la sintesi di carbonati ciclici tramite reazione tra CO2 ed epossidi in condizioni di reazione solvent-free (…
Design of POSS-Imidazolium Supported Hybrids for the Conversion of Carbon Dioxide into Cyclic Carbonates
Nowadays, the design of heterogeneous catalysts for the conversion of CO2 into useful chemical products is attracting the attention of the scientific community. The catalytic processes involving carbon dioxide as C1 feedstock are of growing interest for the sustainable development.1 The synthesis of cyclic carbonates by coupling CO2 with epoxides is one of the most interesting pathways for the conversion of carbon dioxide in terms of both atom economy and final products applications. Moreover, ionic liquids emerged as one of the most active catalysts for the production of cyclic carbonates starting from CO2 and epoxides.2 Herein, a series of heterogeneous catalytic systems bearing imidazoli…
Supported Poly(Ionic Liquid)-Heteropolyacid Based Materials for Heterogeneous Catalytic Fructose Dehydration in Aqueous Medium
Two sets of four different supported catalyst materials were prepared. One set was obtained by polymerization of a bis-vinylimidazolium salt, which formed a poly(ionic liquid) coating on SiO2, TiO2, boron nitride BN, and carbon nitride C3N4. The other set was, instead, obtained by immobilizing Keggin heteropolyacid H3PW12O40 onto poly-imidazolium functionalized materials. All the catalysts, including the bare supports, were subjected to physical and chemical characterization by XRD, SEM, Specific Surface Area and pore size measurements, TGA, FTIR, and acidity-basicity measurements. The catalytic activity of the materials was tested versus the fructose dehydration in water solution at two di…
Exploring the cellular uptake of hectorite clay mineral and its drug carrier capabilities.
In the last years, the use of clay minerals for pharmaceutical purposes has increased due to their interesting properties. Hectorite (Ht) is a clay belonging to the smectite group which has attracted attention for applications in biology, tissue engineering and as drug carrier and delivery system. However, the mechanisms involved in Ht cellular uptake and transport into cells, are still unclear. Herein, we used a labeled Ht (Ht/1Cl) to study both the cellular uptake, by confocal laser scanning microscopy, and internalization pathways involved in the cellular uptake, by various endocytosis-inhibiting studies and fluorescence microscopy. These studies highlighted that Ht can penetrate the cel…
Cross-Linked Polyamine from Imidazolium-Based Materials: A Simple Route to Useful Catalytic Materials
Cross-linked polyamine-based materials were easily prepared by reduction of the corresponding cross-linked imidazolium-based materials with sodium borohydride in hot ethanol. Overall, the synthetic procedure is based on the polymerization of a suitable bis-vinylimidazolium salt with or without a suitable support, such as silica or silica-coated magnetic nanoparticles (γ-Fe2O3@SiO2), followed by reduction. This simple approach allows the synthesis of materials based on a network of secondary and tertiary amines. Materials were characterized by13C cross-polarization magic angle spinning NMR (13C CPMAS NMR), proton spin-lattice relaxation times in the rotating frame (T1ÏH) and thermogravimet…
Supported Imidazolium Functionalized POSS Hybrids as Palladium Platform for C-C Cross-Couplings
Lo sviluppo di catalizzatori per i processi di conversione della CO2 è una tematica che sta rivestendo un ruolo di rilevante importanza in ambito non soltanto accademico ma anche industriale grazie alla possibilità di trasformare un rifiuto, quale il diossido di carbonio, in una vasta gamma di prodotti. Nel presente lavoro, nuovi materiali ibridi costituiti da silsesquiossani poliedrici oligomerici (POSS) supportati su silice e funzionalizzati con sali di imidazolio sono stati progettati per la fissazione della CO2. 1 Tutti i solidi sono stati ampiamente caratterizzati e testati per la sintesi di carbonati ciclici tramite reazione tra CO2 ed epossidi in condizioni di reazione solvent-free (…
Imidazolium-Functionalized Carbon Nanohorns for the Conversion of CO2 Unprecedented Increase of Catalytic Activity after Recycling
Carbon nanohorns (CNHs) were selected as a novel catalytic platform for the design of imidazolium based hybrid materials able to promote the conversion of carbon dioxide into cyclic carbonates. Several heterogeneous catalysts were prepared using a one-step procedure based on the radical polymerization of various bis-vinylimidazolium salts in the presence of pristine CNHs. The as-synthesized materials were tested for the fixation of CO2 into epoxides. The excellent catalytic performances were evaluated in terms of turnover number and productivity. The versatility of the above hybrids was proved using several epoxides as substrate. Catalysts recyclability was successfully verified for several…
Catalizzatori a base di nanocorni di carbonio-liquidi ionici per la conversione della CO2
Nel presente lavoro sono stati impiegati nanocorni di carbonio (CNHs) come piattaforma catalitica per il design di nuovi materiali ibridi a base di sali di imidazolio per la conversione della CO2 in carbonati ciclici. A tale scopo sono stati preparati una serie di catalizzatori eterogenei mediante una procedura sintetica one-pot basata sulla polimerizzazione radicalica di vari sali di bis vinilimidazolio in presenza di nanocorni di carbonio. I suddetti materiali sono stati caratterizzati e testati con successo per la reazione di fissazione della CO2 in epossidi (Figura 1). Figura 1 Conversione della CO2 catalizzata da liquidi ionici supportati su CNHs Le performances catalitiche, valutate i…
Imidazolium Based Cross-Linked Nanostructures from POSS molecular bricks for the Efficient Conversion of Carbon Dioxide
Polyhedral oligomeric silsesquioxanes (POSS) have been employed as molecular bricks for the synthesis of imidazolium cross-linked networks as heterogeneous catalyst for the conversion of carbon dioxide into cyclic carbonates via reaction with epoxides. Two hybrid materials with different nucleophilic species (bromide and iodide) have been prepared and characterized by means of elemental analysis, 13C and 29Si solid state NMR, thermogravimetric analysis and IR spectroscopy. The solids were tested as the sole catalyst under metal- and solvent-free reaction conditions showing full selectivity toward the formation of cyclic carbonates and outstanding productivity values. Several epoxides were r…
Antifouling Systems Based on a Polyhedral Oligomeric Silsesquioxane-Based Hexyl Imidazolium Salt Adsorbed on Copper Nanoparticles Supported on Titania
The reaction of octakis(3-chloropropyl)octasilsesquioxane with four equivalents of 1-hexylimidazole or 1-decylimidazole gave two products labelled as HQ-POSS (hexyl-imidazolium quaternized POSS) and DQ-POSS (decyl-imidazolium quaternized POSS) as regioisomer mixtures. An investigation of the biological activity of these two compounds revealed the higher antimicrobial performances of HQ-POSS against Gram-positive and Gram-negative microorganisms, proving its broad-spectrum activity. Due to its very viscous nature, HQ-POSS was adsorbed in variable amounts on the surface of biologically active oxides to gain advantages regarding the expendability of such formulations from an applicative perspe…