Non-hydrolytic Sol Gel Reaction Research Articles

Lewis Acidic Aluminosilicates: Synthesis, 27Al MQ/MAS NMR, and DFT-Calculated 27Al NMR Parameters.

Porous aluminosilicates are functional materials of paramount importance as Lewis acid catalysts in the synthetic industry, yet the participating aluminum species remain poorly studied. Herein, a series of model aluminosilicate networks containing [L-AlO3] (L = THF, Et3N, pyridine, triethylphosphine oxide (TEPO)) and [AlO4]- centers were prepared through nonhydrolytic sol-gel condensation reactions of the spherosilicate building block (Me3Sn)8Si8O20 with L-AlX3 (X = Cl, Me, Et) and [Me4N] [AlCl4] compounds in THF or toluene. The substoichiometric dosage of the Al precursors ensured complete condensation and uniform incorporation, with the bulky spherosilicate forcing a separation between neighboring aluminum centers. The materials were characterized by 1H, 13C, 27Al, 29Si, and 31P MAS NMR and FTIR spectroscopies, ICP-OES, gravimetry, and N2 adsorption porosimetry. The resulting aluminum centers were resolved by 27Al TQ/MAS NMR techniques and assigned based on their spectroscopic parameters obtained by peak fitting (δiso, CQ, η) and their correspondence to the values calculated on model structures by DFT methods. A clear correlation between the decrease in the symmetry of the Al centers and the increase of the observed CQ was established with values spanning from 4.4 MHz for distorted [AlO4]- to 15.1 MHz for [THF-AlO3]. Products containing exclusively [TEPO-AlO3] or [AlO4]- centers could be obtained (single-site materials). For L = THF, Et3N, and pyridine, the [AlO4]- centers were formed together with the expected [L-AlO3] species, and a viable mechanism for the unexpected emergence of [AlO4]- was proposed.

Non-hydrolytic sol-gel synthesis of zirconium phosphonates with controlled mesoporosity

We disclose the preparation of high-surface-area mesoporous zirconium phosphonates by the non-hydrolytic sol-gel reactions (NHSG) of Zr(NEt2)4 with trimethylsilylated phosphonates RP(O)(OSiMe3)2 (R = Me, tBu, Ph, OSiMe3), and bis-phosphonates (Me3SiO)2(O)P–X–P(O)(OSiMe3)2 (X = CH2, C6H4, CH2(C6H4)CH2, and CH2(C6H4)2CH2) in dry toluene under ambient pressure. Zirconium phosphonate xerogels are prepared by condensation reaction with the elimination of silylamine Me3SiNEt2. This irreversible reaction provides the amorphous xerogels and drives the formation of the porous structure. The influence of organic moieties bonded to phosphorus atoms on porosity was examined in this study. The final surface area of dried xerogels reached 720 m2 g−1 without any extra templating agent. Xerogels were characterized by 13C, 29Si, and 31P solid-state NMR to define atomic homogeneity and evidence the presence of organic phosphonate substituents and residual amido and trimethylsilyl groups. The amount of residual reactive groups was determined by gravimetric measurements and the thermal analysis (TG-DSC) method. These groups may be applied in post-synthetic surface modification, such as controlling the hydrophobic/hydrophilic properties.The catalytic properties of NHSG-prepared xerogels were tested on a model reaction of aminolysis of styrene oxide in a batch mode employing relatively bulky molecules. Products were identified and quantified by the 1H NMR spectroscopy. Catalyst performance parameters, such as selectivity, conversion, turnover frequency, and others, were exceeded compared to benchmark microporous layered zirconium phosphonate catalysts.

#5333 IMPROVING AUTOPHAGY FLUX BY TFEB ACTIVATION WITH CERIA NANOPARTICLES ATTENUATED CHRONIC KIDNEY INJURY IN CELLULAR AND ANIMAL MODELS OF FABRY DISEASE

Abstract Background and Aims Fabry disease (FD) is a lysosome storage disease (LSD) characterized by significantly reduced intracellular autophagy function. This contributes to the progression of intracellular pathologic signaling and can lead to organ injury. Phospholipid–polyethyleneglycol-capped Ceria-Zirconia antioxidant nanoparticles (PEG-CZNPs) have been reported to enhance autophagy flux. We accessed the action mechanisms of PEG-CZNPs in autophagy regulation and checked the effect on chronic kidney injury in cellular and animal models of FD. Method PEG-CZNPs were synthesized using a non-hydrolytic sol-gel reaction method. HK-2 cells were transfected with α-galactosidase A (α-GLA) shRNA for permanent cellular model of FD. For in-vivo study 4-week-old male B6;129-Glatm1Kul/J mice were treated for 48 weeks with 10mg/kg of PEG-CZNPs twice per week via intraperitoneal injection. PCR, immunoblotting, immunoflouresce assay, electron microscopy analysis, ICP-MS, biochemical and histological analysis were done Results TFEB tanslocated to the nucleus by treatment with PEG-CZNPs. Autophagy flux was evaluated with chloroquine. Autophagy flux was enhanced by PEG-CZNPs treatment. To show whether TFEB plays the important role in autophagy flux, we transfected HK-2 cells with siTFEB. Autophagy flux significantly decreased after knockdown of TFEB with PEG-CZNPs treatment. We next assessed upper signaling pathway of TFEB by PEG-CZNPs. TFEB dephosphorylation was independent of both mTOR and ERK but GSK3ß signaling pathway showed massive impact on TFEB dephosphoryation by PEG-CZNPs. PEG-CZNPs decrease intracellular globotriaosyceramide (Gb3) accumulation and decreased the levels of Collagen type IV, αSMA and MMP9 expression in cellular model of FD. Gb3 levels were significantly reduced in the kidney tissues and the levels of Fibronectin, Collagen type 4 and αSMA was decreased by PEG-CZNPs in animal model of FD. Conclusion These results suggested PEG-CZNPs promote autophagy flux through GSK3ß -TFEB signaling pathways, showed the beneficial effect on renal fibrosis in cellular and animal models of FD. It thus provided a new insights of the potential therapeutics on FD.

Polyzwitterion–SiO2 Double-Network Polymer Electrolyte with High Strength and High Ionic Conductivity

The key to developing high-performance polymer electrolytes (PEs) is to achieve their high strength and high ionic conductivity, but this is still challenging. Herein, we designed a new double-network PE based on the nonhydrolytic sol-gel reaction of tetraethyl orthosilicate and in situ polymerization of zwitterions. The as-prepared PE possesses high strength (0.75 Mpa) and high stretchability (560%) due to the efficient dissipation energy of the inorganic network and elastic characteristics of the polymer network. In addition, the highest ionic conductivity of the PE reaches 0.44 mS cm-1 at 30 °C owning to the construction of dynamic ion channels between the polyzwitterion segments and between the polyzwitterion segments and ionic liquids. Furthermore, the inorganic network can act as Lewis acid to adsorb trace impurities, resulting in a prepared electrolyte with a high electrochemical window over 5 V. The excellent interface compatibility of the as-prepared PE with a Li metal electrode is also confirmed. Our work provides new insights into the design and preparation of high-performance polymer-based electrolytes for solid-state energy storage devices.

Chemical route for synthesis of β-SiAlON:Eu2+ phosphors combining polymer-derived ceramics route with non-hydrolytic sol-gel chemistry

We report the synthesis of β-SiAlON:Eu2+ phosphors from novel single source precursors in which strictly controlled chemical composition is established at molecular scale. The two-step synthesis occurs by the chemical modification of perhydropolysilazane (PHPS) with Al(OCH(CH3)2)3 and AlCl3 in xylene at room temperature to 140 °C to introduce Al in the PHPS network while controlling the oxygen content followed by the reaction of EuCl2 with the Al-modified PHPS upon heat-treatment. Gas chromatography-mass spectrometry and thermogravimetry-mass spectrometry analyses revealed that PHPS reacted with Al(OCH(CH3)2)3 and AlCl3 via the formation of Al-N bonds. Moreover, AlCl3 reacted with nitrogen-bonded Al alkoxide residue to release 2-chloropropane in an analogy to the non-hydrolytic sol-gel reaction between metal alkoxide and metal chloride. Subsequently, AlCl3 acted as a Lewis acid catalyst to promote the Friedel-Craft alkylation between xylene solvent and the 2-chloropropane formed in-situ to afford dimethylcumene. On the other hand, EuCl2 reacted with silylamino moiety to form Eu-N bonds at around 850 °C. β-SiAlON:Eu2+ phosphors were successfully synthesized by pyrolysis of the precursors under flowing N2 or NH3 at 1000 °C, followed by heat treatment at 1800 °C for 1 h under a N2 gas pressure at 980 kPa. The polymer-derived β-SiAlON:Eu2+ (z = 0.55, Eu2+ 0.37 at%) exhibited green emission under excitation at 410 or 460 nm, and the green emission intensity under the excitation at 410 nm was found to be increased by reducing the carbon and chlorine impurities through the polymer-derived ceramics route investigated in this study.

Tuning Polymer/TiO2 Nanocomposites Morphology by In Situ Non-Hydrolytic Sol-Gel Syntheses in Viscous Polymer Medium: Influence of the Polymer Nature and Oxygen Donor.

Herein, we reported the synthesis of TiO2 through different non-hydrolytic sol-gel (NHSG) routes in viscous polymer media. For the first time, the influence of the polymer nature (Polystyrene (PS) or Polypropylene (PP)) on the morphology of synthesized inorganic domains was investigated. The non-hydrolytic sol-gel reactions between titanium isopropoxide Ti(OiPr)4 and acetic anhydride in molten polypropylene lead to the formation of microfillers with a mean diameter of about 1 μm, while the same synthesis carried out in viscous polystyrene lead to the formation of nanofillers with diameter lower than 10 nm forming aggregates of approximately 200 nm. We have also investigated the influence of the oxygen donor nature on the morphology of synthesized fillers using aromatic oxygen donors in a polystyrene matrix. The use of benzoic anhydride or acetophenone as oxygen donors with Ti(OiPr)4 in viscous polystyrene lead to respectively platelet-like morphology or aggregated nanofillers. We demonstrated that the affinity between polymer, reactants, and/or by-products had an influence on the morphology and the size of in situ synthesized TiO2 fillers. These results evidenced for the first time the possibility to control and to tune the morphology of in situ grown inorganic objects through the NHSG process by the appropriate choice of solvent, here a viscous polymer medium, and reactants.

Halide Replacement with Complete Preservation of Crystal Lattice in Mixed-Anion Lanthanide Oxyhalides.

A challenge in anion control in periodic solids is to preserve the crystal lattice while substituting for different anions of widely varying size and hardness. Post-synthetic modification routes that place cations or anions in non-equilibrium configurations are promising; however, such methods remain relatively unexplored for anion placement. Here, we report the synthesis of LaOI nanocrystals by a non-hydrolytic sol-gel condensation reaction and their transformation into LaOBr, LaOCl, and LaOF nanocrystals along hard-soft acid-base principles using post-synthetic metathesis reactions with ammonium halides. Anion displacement proceeds along halide planes, preserving the tetragonal matlockite structure. Energy-variant X-ray excited optical luminesce signatures of alloyed Tb3+ -ions is a sensitive quantum reporter of the preservation of the cation sublattice and hardening of the crystal structure upon anion replacement.

Non-hydrolytic sol–gel synthesis of polypropylene/TiO2 composites by reactive extrusion

An original way to synthesise polypropylene/titanium dioxide (PP/TiO2) composites combining non-hydrolytic sol–gel chemistry and reactive extrusion was reported. The non-hydrolytic sol–gel reaction between titanium alkoxide as a titanium dioxide precursor and an acid anhydride as an oxygen donor at 240 °C was first evaluated and optimised in an alkane liquid medium. TiO2 was present essentially in crystalline anatase form when synthesised in squalane with a domain size around 10 nm. Based on these encouraging results, the synthesis was adapted to reactive extrusion that means at high temperature in molten viscous polypropylene and for short reaction times (few minutes maximum). The proof of concept was evidenced through the formation of amorphous TiO2-based inorganic domains of size around 1 µm within the polymer matrix from the reaction between titanium isopropoxide and acetic anhydride. A condensation degree of 79% was obtained. To optimise the polymer/filler interface, titanium dioxide precursors and oxygen donors with different alkyl chain lengths were evaluated. Hexanoic anhydride as substituent of acetic anhydride and titanium tetrakis 2-ethylhexyloxide as substituent of titanium isopropoxide were used. The oxygen donor contribution appeared to be dominant for the particle dispersion state. The polypropylene (PP)/TiO2 composite synthesised from the reaction between titanium isopropoxide and hexanoic anhydride showed the narrowest TiO2 particle diameter distribution with a mean particle size around 700 nm.

Synthesis of high surface area aluminophosphate and -phosphonate xerogels by non-hydrolytic sol-gel reactions

We disclose the preparation of high-surface-area mesoporous aluminophosphates and aluminophosphonates by the non-hydrolytic sol-gel reactions (NHSG) of Al(NMe 2 ) 3 with trimethylsilylated phosphate OP(OSiMe 3 ) 3 , phosphonates RP(O)(OSiMe 3 ) 2 (R = Me, t Bu, Ph), and bis-phosphonates (Me 3 SiO) 2 (O)P–X–P(O)(OSiMe 3 ) 2 (X = C 6 H 4 , (C 6 H 4 ) 2 ) in dry toluene. The reactions proceed by silylamine elimination of Me 3 SiNMe 2 to provide organic-inorganic hybrid xerogels with properties influenced by organic substituents and the Al:P ratio of the precursors. Dried xerogels exhibit large surface areas (up to 1000 m 2 g −1 ) and matrices based on condensed Al–O–P networks. They stay stable under relatively harsh thermal conditions. 27 Al, 13 C, and 29 Si solid-state NMR spectroscopy was employed to characterize the aluminum coordination and the residual amido and trimethylsilyl groups. The catalytic performance of NHSG prepared material was examined in gas-phase dehydration of ethanol to ethylene exhibiting conversion and selectivity comparable to weak solid acid benchmark catalysts. The number of unreacted surface groups was determined by gravimetric measurements and by thermal analysis (TG-DSC). These residual groups have the potential to be used in post-synthetic grafting of catalytically active metal centers. • Aluminophosphates and aluminophosphonates are prepared by non-hydrolytic sol-gel synthesis. • Mesoporous xerogels with large surface areas (1030 m 2 g -1 ). • Gas-phase dehydration of ethanol to ethylene with good conversion and selectivity.

Preparation of Titanium-silphenylene-siloxane Hybrid Polymers with High Refractive Index, Transmittance, and Thermal Stability

Vinyl-containing titanium-silphenylene-siloxane oligomers (O1, O2, O3, and O4) with different molar ratios of titanium to silicon were successfully synthesized in high yields by nonhydrolytic sol-gel reaction, and the obtained four oligomers were further crosslinked with methylphenyl hydro-silicone oil (4) to form corresponding polymers (P1, P2, P3, and P4) by hydrosilylation reaction. Their structures were characterized with spectroscopic characterization techniques including FTIR, 1H-NMR, and Raman spectroscopy. The effect of titanium element on crosslinking behavior, thermal resistance, refractive index, transparency, thermal aging stability, glass transition temperature, and surface properties of the polymers were studied. Compared with titanium-free polymer P1, the thermal resistance, refractive index, and thermal aging stability of titanium-silphenylene-siloxane polymers (P2, P3, and P4) were significantly improved. The titanium-silphenylene-siloxane polymers achieved a high refractive index (n = 1.580–1.584) and thermostability (T5d > 500 °C). In thermal aging, the polymers exhibited superior performances with high optical transparency (~90% at 450 nm) and exhibited high thermal stability (~84% at 450 nm after thermal aging at 150 °C for 120 h). These data indicate that the polymers have potential application in optical materials such as LED encapsulants.

Highly Tough, Li‐Metal Compatible Organic–Inorganic Double‐Network Solvate Ionogel

AbstractIonogels are considered promising electrolytes for safe lithium‐ion batteries (LIBs) because of their low flammability, good thermal stability, and wide electrochemical stability window. Conventional ionic liquid‐based ionogels, however, face two main challenges; poor mechanical property and low Li‐ion transfer number. In this work, a novel solvate ionogel electrolyte (SIGE) based on an organic–inorganic double network (DN) is designed and fabricated through nonhydrolytic sol–gel reaction and in situ polymerization processes. The unprecedented SIGE possesses high toughness (bearing the deformation under the pressure of 80 MPa without damage), high Li‐ion transfer number of 0.43, and excellent Li‐metal compatibility. As expected, the LiFePO4/Li cell using the newly developed SIGE delivers a high capacity retention of 95.2% over 500 cycles, and the average Coulombic efficiency is as high as 99.8%. Moreover, the Ni‐rich LiNi0.8Co0.1Mn0.1O2 (NCM811)/Li cell based on the modified SIGE achieves a high Coulombic efficiency of 99.4%, which outperforms previous solid/quasi‐solid‐state NCM811‐based LIBs. Interestingly, the SIGE‐based pouch cells are workable under extreme conditions (e.g., severely deforming or clipping into segments). In terms of those unusual features, the as‐obtained SIGE holds great promise for next‐generation flexible and safe energy‐storage devices.

P-215 - Ceria-Zirconia nanoparticles as an enhanced multi-antioxidant attenuates apoptosis of human kidney proximal tubular epithelial cells in hypoxia

Aims Ischemia/reperfusion injury, resulting from hypoxic damage within a graft, is the leading cause of cell death and graft rejection. In this study, we investigated whether Ceria-Zirconia nanoparticles (CZ NPs) as an enhanced multi-antioxidant have a great role in ischemic injury in a cellular model in which experimental hypoxia was induced using CoCl2. Main methods The ischemic injury induced in HK-2 cells by CoCl2 was validated by reduced cell viability at different times and doses. CZ NPs with size 2–3 nm were synthesized using non-hydrolytic sol-gel reaction. Results Cellular survival was reduced in a dose-dependent manner for 24 h after CoCl2 exposure. Because approximately 70% of cells survived after treatment with 300 µM of CoCl2 for 24 h, this dose was chosen for further study. CoCl2 caused a significant increase in ROS production 2 h after CoCl2. The extent of the effect of CoCl2 on ROS levels was significantly reduced by CZ NPs treatment. CZ NPs down-regulated proinflammatory markers and reduced caspase 3/7 activity in hypoxic HK-2 cells. CZ NPs also improved the survival of HK-2 cells in response to hypoxia. Conclusions CZ NPs have the potential as a therapeutic medicine for preventing ROS-related ischemia reperfusion injury after transplantation.

Preparation of plant derived carbon and its application for inclusion pigments

Plant derived carbon was utilized as a new financial and environmental friendly colorant in the synthesis of zircon encapsulated carbon pigment (C@ZrSiO4) via non-hydrolytic sol-gel method. After calcining, nature plants, i.e. sisal and bamboo leaves, were carbonized and occluded in ZrSiO4 matrix. The FT-IR and XRD results demonstrated that the plants were not affect the non-hydrolytic sol-gel polycondensation reaction, resulting in the pure ZrSiO4 formation. Both inclusion pigments presented deep black hue, i.e. L∗ = 34.93 and 33.02 for sisal and bamboo leaves, respectively, which was contributed to the homogeneous pore-size distribution and high carbon yield of the plants. These pigments have many distinguished advantages including low cost, high chromatic performance and excellent thermal stability, making them promising candidates for ceramic decoration.

The synthesis, characterization and properties of silicone adhesion promoters for addition-cure silicone rubber

Two types of polysiloxanes, GVPMS and GVHMS, were synthesized through nonhydrolytic sol-gel reaction from vinyltrimethoxysilane(VTMS), 3-glycidoxypropyltrimethoxysilane(KH560) and diphenylsilandiol(DPSD) or hydroxyl silicone oil, respectively. The chemical structures were characterized by Fourier transform infrared (FTIR) spectroscopy, 1H nuclear magnetic resonance (1H-NMR) spectroscopy and gel permeation chromatography (GPC). GVPMS and GVHMS were used as adhesion promoter for addition-cure silicone rubber. It was found that the adhesion promoters not only greatly improved adhesion strength but also had excellent compatibility with silicone rubber. Among them, GVPMS gave better adhesion strength in silicone rubber. The shear strength of silicone rubber reached 1.70 MPa with addition of 1.5 phr GVPMS, which was about 317% higher than that of silicone rubber without the adhesion promoter. Meanwhile, the shear strength of silicone rubber reached 1.14 MPa with addition of 2.0 phr GVHMS, which was 183% higher than that of silicone rubber without the adhesion promoter. Optical property test results revealed that the refractive indexes of GVPMS and GVHMS were 1.5185 and 1.4133 respectively and both of them had good compatibility with silicone rubber, which satisfied the application demand of high-refractive and low-refractive electron encapsulation. Thermal resistance test and SEM results further proved that adhesion promoter could significantly increase the adhesion between the copper substrate and silicone rubber, in which GVPMS had a better performance. Oxidation treatment experiment further explained the mechanism that adhesion promoter functioned as a bridge, linked silicone rubber and copper substrate through chemical bonds.

Synthesis of phenyl silicone resin with epoxy and acrylate group and its adhesion enhancement for addition-cure silicone encapsulant with high refractive index

A novel phenyl silicone resin with epoxy and acrylate group (PSREA) was successfully synthesized via the non-hydrolytic sol-gel condensation reaction of 3-glycidoxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, and diphenylsilanediol, and was employed as the adhesion promoter for addition-cure silicone encapsulant (ASE) with high refractive index. The structure of PSREA was confirmed by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance spectroscopy, and 29Si nuclear magnetic resonance spectroscopy. The influence of PSREA on the properties of ASE was studied. It was found that PSREA could markedly enhance the adhesion strength of ASE to aluminum (Al) and poly(p-phenylene terephthamide) (PPA) substrate. When the content of PSREA was 1.5 phr, the shear strength of ASE was 4.43 and 2.27 MPa for Al and PPA substrate, which was about 71 and 266% higher than that of ASE without the adhesion promoter, respectively. In addition, PSREA had little effect on the mechanical properties, refractive index, and viscosity of ASE.

“Non-hydrolytic” sol–gel synthesis of molybdenum sulfides

Non-hydrolytic sol–gel reactions provide a low temperature solution based synthetic approach to solid-state materials. In this paper, reactions between molybdenum chloride and hexamethyldisilthiane in chloroform were explored, which gave access to both MoS2 and Mo2S3 after heat treatment of as-recovered amorphous samples to 600–1000°C. Interesting morphologies were obtained for MoS2, ranging from fused spherical particles to well-defined nanoplatelets and nanoflakes. Both 2H- and 3R-MoS2 were observed, which formed thin hexagonal and triangular platelets, respectively. The platelets exhibited thicknesses of 10–30nm, which corresponds to 15–50 MoS2 layers. No attempts to prevent agglomeration were made, however, well separated platelets were observed for many samples. Heating at 1000°C led to formation of Mo2S3 for samples that showed well-defined MoS2 at lower temperatures, while less crystalline samples had a tendency to retain the MoS2 structure.

Formulation influence on the sol–gel formation of silica-supported ionogels

Ionic liquids (ILs) present many new opportunities for the field of sol–gel chemistry. When conducted in an IL medium, sol–gel chemistry can produce novel silica structures as well as hybrid materials known as ionogels, which feature ILs supported by a solid scaffold material. In this work, the influence of reactive formulation on the properties of silica-supported ionogels is reported. A simple, non-hydrolytic sol–gel reaction between tetramethoxysilane and formic acid is employed to create silica-supported ionogels that exhibit wide variations in silica content, gelation time, and mechanical character. The influence of formulation on gelation time is demonstrated, and it is shown that a range of formulations can be used to produce soft, mechanically compliant ionogels. Furthermore, either brittle or compliant ionogels can be realized via rapid- or slow-gelling formulations. It is observed that the speed of gelation influences the pore structure in the resultant silica scaffold, thereby enabling different mechanical characters to be achieved for ionogels containing equivalent silica mass fractions.

Colloidal Nanoclusters of MgO Coated with Alkali Metal Nitrates/Nitrites for Rapid, High Capacity CO2 Capture at Moderate Temperature

Colloidal nanoclusters of metal oxides constitute a promising new class of building blocks for a range of advanced functional materials. Herein, we report on the development of colloidal nanoclusters of MgO for CO2 capture prepared by a novel nonhydrolytic sol–gel reaction followed by the deposition of alkali metal salts by methanol evaporation-induced surface precipitation. The CO2 uptake exceeded 11.7 mmol g–1 (514.8 mg CO2 per 1 g of adsorbent) in 30 min in the presence of 100% dry CO2 under ambient pressure (1 bar) at 340 °C and reached 15.7 mmol g–1 (690.8 mg CO2 per 1 g of adsorbent) in 4 h. Colloidal nanoclusters possessing multiple inner grain boundaries and rough surfaces allowed for a dramatic increase in active surface area of MgO coated with thin layers of alkali metal salts and enabled the rapid conversion of MgO to MgCO3 with high conversion ratio. It was also discovered that the CO2 uptake loading and the regenerability of the sorbents can be enhanced on introduction of nitrite salts to the...

Mesoporous titanosilicates by templated non-hydrolytic sol–gel reactions

A novel templated non-hydrolytic sol–gel synthesis of titanosilicate xerogels is reported. Acetamide elimination from silicon acetate and titanium diethylamide allows obtaining titanosilicates with a high content of Si–O–Ti bonds but low surface areas. These xerogels lose porosity on calcination. However, with addition of Pluronic P123 as a structure-directing agent, we synthesized mesoporous titanosilicate materials with large surface areas (up to 615 m2 g−1) and well dispersed tetrahedral Ti that are stable at temperatures up to 500 °C. These potential catalysts were characterized by variety of physico-chemical methods (IR, GC–MS, XRD, 29Si and 13C CPMAS NMR, DRUV-Vis, and N2 porosimetry) and tested in cyclohexene epoxidation with cumyl hydroperoxide in toluene. They display catalytic activity with the 100 % selectivity to cyclohexene oxide and high catalytic yields up to 96 % which is comparable to previously reported titanosilicate catalysts.

Non-aqueous template-assisted synthesis of mesoporous nanocrystalline silicon orthophosphate

Mesoporous nanocrystalline silicon orthophosphate Si5P6O25 was synthesized by the non-hydrolytic sol–gel reaction in the presence of Pluronic P123 template and displays superior catalytic activity and selectivity in methylstyrene dimerization.