Synthesis of Fe‐loaded MFI zeolite using silatrane as precursor and its CO activity

Fe‐MFI zeolite was successfully synthesized using silatrane as precursor and tetrapropyl ammonium bromide as template via the sol–gel process and microwave heating technique. The effects of ageing time, heating temperature, heating time and iron concentration were investigated, and it was found that Fe‐MFI synthesis favors higher heating temperatures, but is limited by the degradation of the incorporation of a template molecule. Moreover, longer ageing and heating times promote the incorporation of higher amounts of iron atom in the MFI structure. However, too long an ageing time decreases the incorporation of iron. The lower the percentage Fe loading, the greater the percentage of Fe³⁺ ions incorporated into the MFI framework. The catalytic activity of Fe‐MFI catalyst for the oxidation of CO was studied and it was found that these synthesized catalysts catalyzed the oxidation of CO very well. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis of Ti‐MCM‐41 directly from silatrane and titanium glycolate and its catalytic activity1

Titanium is successfully incorporated in hexagonal mesoporous silica to form Ti‐MCM41 at low temperature. Silatrane and titanium glycolate synthesized from the oxide one‐pot synthesis process are used as the precursors. Using the cationic surfactant cetyltrimethylammonium bromide as a template, the resulting meso‐structure mimics the liquid‐crystal phase. The percentage of titanium loading is varied in the range 1–35%. The temperatures used in the preparation are 60 °C and 80 °C. After heat treatment, very high surface area mesoporous silica was obtained and characterized using diffuse reflectance UV (DRUV) spectroscopy, X‐ray diffraction (XRD), BET surface area, X‐ray fluorescence, energy dispersive spectroscopy and transmission electron microscopy (TEM). At 35% titanium, the titanium atom is also in the framework showing the pattern of hexagonal mesostructure, as shown by DRUV, XRD and TEM results. The surface area is extraordinarily high, up to more than 2300 m² g^?1, and the pore volume is as high as 1.3 cm³ g^?1 for a titanium loading range of 1–5%. Oxidative bromination reaction using Ti‐MCM‐41 as catalyst showed impressive results, with the 60 °C catalysts having higher activity. Copyright © 2005 John Wiley & Sons, Ltd.     

Stable second‐order nonlinear optical poly(amide–imide)/inorganic materials via simultaneous sequential self‐repetitive reaction and sol–gel process

A series of thermally stable organic/inorganic second‐order nonlinear optical (NLO) composites via sequential self‐repetitive reaction (SSRR) and sol–gel process has been developed. This SSRR is based on carbodiimide (CDI) chemistry. The difunctional azo chromophores (2,4‐diamino‐4′‐(4‐ nitrophenyl‐diazenyl)azobenzene (DNDA)) was reacted with excessive amount of 4, 4′‐methylene‐ diphenylisocyanate (MDI) to form poly‐CDI, and subsequently trimellitic anhydride (TMA) was added to obtain poly(N‐acylurea). The organic/inorganic composites containing prepolymer of phenyltriethoxysilane (PTEOS) and poly(N‐acylurea) in different weight ratios (10:90, 30:70, 50:50, 70:30, 90:10 wt%) were prepared, respectively. The moderate glass transition temperature (T_g) characteristic of the poly(N‐acylurea) allows the NLO‐active polymer to achieve high poling efficiency. After in situ poling and curing process, the T_gs of the composites were elevated, and higher than that of the pristine poly(amide–imide) sample. Electro‐optical (EO) coefficients (r₃₃) of about 5.5 ～ 18.0 pm/V at 830 nm were obtained. Excellent temporal stability at 100°C, and waveguide characteristics (3.1–4.2 dB/cm at 830 nm) were also obtained for these composites. Copyright © 2008 John Wiley & Sons, Ltd.     

Anionic surfactant‐aided preparation of high surface area and high thermal stability ceria/zirconia‐mixed oxide from cerium and zirconium glycolates via sol–gel process and its reduction property

This work is focused on the ceria zirconia mixed oxide prepared through a surfactant‐introduced synthesis method. High surface area nanoparticle mesoporous ceria/zirconia‐mixed oxide was successfully synthesized and characterized using various techniques. High surface area mesoporous fluorite‐structured CeO₂? ZrO₂ was obtained from the elimination of surfactants upon calcination. A surface area in excess of 205.6 m²/g was obtained after calcination at 500 °C, and dropped to 75.96 m²/g by heating at 900 °C. Temperature‐programming reduction (TPR) results showed that the lowest reduction temperature was obtained from the sample containing 40% zirconia content. Copyright © 2008 John Wiley & Sons, Ltd.     

Removal of Copper‐phthalocyanine from Aqueous Solution by Cationically Templated MCM‐41 and MCM‐48 Nanoporous Adsorbents

The effect of cationic template on the adsorption of copper-phthalocyanine-3,4’,4",4"’-tetrasulfonic acid tetra-     

The alkoxide sol–gel process in the calcium phosphate system and its applications†

A single calcium glycolate was synthesized. The alkoxide was stable under ambient atmosphere. The calcium glycolate, phosphoric acid and P(OH) _x (OEt)_{3− x} were used as the precursors. Acetic acid was used as a reagent to modify the calcium glycolate and to change the acidity of the mixtures of the precursors. Mixtures of the calcium glycolate and phosphoric acid in a Ca/P ratio of 1.67 showed unusual sol–gel behavior. A transparent gel could be formed depending on the content of acetic acid and the extent of stirring. The behavior is attributed to a high viscosity and a large molecular size of the ethylene glycol solvent, leading to a strong dependence of the reactions in the mixtures on the diffusion process, greatly affected by stirring. When the mixtures of the calcium glycolate and PO(OH) _x (OEt) _{3− x} contained acetic acid at an acetic acid/Ca ratio of 3, stable alkoxide solutions with Ca/P ratios of 1.0, 1.5 and 1.67 could be formed. Different calcium phosphate compounds and hydroxyapatite coatings on alumina substrates could easily be formed from the alkoxide solutions. The chemical homogeneity provided by the alkoxide route leads to easy formation of the required products. Copyright © 1999 John Wiley & Sons, Ltd.     

Preparation and characterization of epoxy/SiO2 nanocomposites by cationic photopolymerization and sol–gel process

Epoxy/SiO₂ nanocomposite materials were prepared by cationic photopolymerization and sol–gel process using a novel epoxy oligomer (EP‐Si(OC₂H₅)₃) prepared by 3‐isocyanatopropyltriethoxysilane (IPTS)‐grafted bisphenol A epoxy resin and tetraethyl orthosilicate as inorganic precursor. The chemical structures of EP‐Si(OC₂H₅)₃ were characterized by Fourier transformed infrared spectroscopy. Transmission electron microscopy showed that the in situ generated nano‐SiO₂ dispersed uniformly in the EP matrix, and its average diameter is around 40 nm. The relationship between nanocomposite materials' thermal/mechanical properties and nano‐SiO₂ introduced were studied by thermogravimetric analysis, dynamic mechanical analysis, and impact strength test. The results showed that the nanocomposite materials' thermal and mechanical properties improved a lot with increase of the SiO₂ content. Copyright © 2013 John Wiley & Sons, Ltd.     

Sonochemical synthesis of library benzodiazepines using highly efficient molecular ionic liquid supported on Fe‐MCM‐41 nanocomposites as a recyclable catalyst

In this study, library substituted benzodiazepines was synthesized using molecular ionic liquid supported on Fe‐MCM‐41 nanocomposites (Fe‐MCM‐41‐IL). This protocol using ultrasound provided advantages such as rapid, clean conversion and simplicity in experimental setup that led to rapid generation of benzodiazepines under mild condition. The catalyst can be easily isolated by using an external magnetic field and reused in the next reaction up to six cycles without obvious activity decreasing.     

Organic–inorganic hybrid membranes prepared from the sol–gel process of poly(butyleneadipate‐co‐terephthalate) and TiO2

Organic–inorganic hybrids based on poly(butyleneadipate‐co‐terephthalate)/titanium dioxide (PBAT/TiO₂) hybrid membranes were prepared via a sol–gel process. The PBAT/TiO₂ hybrid membranes were prepared for various PBAT/TiO₂ ratios. The resulting hybrids were characterized with a morphological structure, hydrophilicity, biodegradability, and thermal properties. The results showed that macrovoids underwent a transition into a sponge‐like membrane structure with the addition of TiO₂. After sol–gel transition, a strong interaction between the inorganic network and polymeric chains led to an increase in glass transition temperature (T_g), thermal degrading temperature, and hydrophilicity, and hence a higher biodegradability. According to X‐ray diffraction measurements of the crystal structure of the hybrid, the presence of TiO₂ did not change the crystal structure of PBAT. TiO₂ networks are uniformly dispersed into the PBAT matrix and no aggregation of TiO₂ networks in the hybrid membranes was observed through the small angle X‐ray scattering measurements. Thus, the sol–gel process of PBAT and TiO₂ can be used to prepare a hybrid with higher application temperature and faster biodegradation rate. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis of ceria–zirconia mixed oxide from cerium and zirconium glycolates via sol–gel process and its reduction property

Ceria–zirconia mixed oxide was successfully synthesized via the sol–gel process at ambient temperature, followed by calcination at 500, 700 and 900 °C. The synthesis parameters, such as alkoxide concentration, aging time and heating temperature, were studied to obtain the most uniform and remarkably high‐surface‐area cubic‐phase mixed oxides. The thermal stability of both oxides was enhanced by mutual substitution. Surface areas of the Ce_xZr_1?xO₂ powders were improved by increasing ceria content, and their thermal stability was increased by the incorporation of ZrO₂. The most stable cubic‐phase solid solutions were obtained in the Ce range above 50 mol%. The highest surface area was obtained from the mixed catalyst containing a ceria content of 90 mol% (200 m²/g). Temperature programmed reduction results show that increasing the amount of Zr in the mixed oxides results in a decrease in the reduction temperature, and that the splitting of the support reduction process into two peaks depends on CeO₂ content. The CO oxidation activity of samples was found to be related to its composition. The activity of catalysts for this reaction decreased with a decrease in Zr amount in cubic phase catalysts. Ce₆Zr₄O₂ exhibited the highest activity for CO oxidation. Copyright © 2006 John Wiley & Sons, Ltd.     

Tubular Morphology of Mesoporous Silica MCM‐41

We investigated detailed conditions for synthesizing the tubular form of MCM‐41 mesoporous aluminosilicate. The method is the delayed neutralization method in which the rate of neutralization is one of the controlling factors. Rapid neutralization results in the particulate form while gradual neutralization leads to tubules. It is found that the tubule morphology has several sub‐categories. There are thick‐walled, think‐walled hollow tubular MCM‐41 and solid core tubules. There are void structures in the channel framework that makes the nanochannels to be effectively interconnected.     

Synthesis and characterization of MCM‐41‐Biurea‐Pd as a heterogeneous nanocatalyst and using its catalytic efficacy in C–C,C–N and C–O coupling reactions

MCM‐41‐Biurea‐Pd is introduced as a new, heterogeneous and reusable catalyst for C–C and C–heteroatom bond formation between various aryl halides, phenols and amines, in the presence of Ph₃SnCl (Stille reaction) in PEG‐400 as a green solvent at room temperature. The structure of the functionalized MCM‐41 was analysed using various techniques.     

Surlyn®/titanate hybrid materials via polymer in situ sol–gel chemistry

Acid form Surlyn®/titanate hybrid materials were achieved by polymer in situ sol–gel reactions for a titanium alkoxide monomer. Atomic force microscopic images revealed arrays of titania nanoparticles having diameters of 10–30 nm. Fourier transform infrared spectra verified the presence of an internally polymerized titanate phase although unhydrolyzed TiOR groups were present. Carboxylic acid dimerization was complete at room temperature, but carboxylate anions appeared at higher titanate levels. The methylene rocking doublet persisted upon incorporation of the inorganic component, which supported the idea of largely undisrupted crystallinity. Thermogravimetric analysis showed that the degradation onset temperature of each hybrid is largely unaffected by the presence of the inorganic filler, which is consistent with the concept of an isolated titanate phase. The first‐scan differential scanning calorimetric thermogram for unfilled Surlyn® revealed the usual twin‐melting endotherms. In contrast, the primary, high‐temperature melting endotherm was seen on the first scan for the Surlyn®/titanate hybrids, but the lower temperature endotherm was either not present or weak. Primary melting persisted after several cycles of heating above the melting temperature followed by cooling, demonstrating that primary crystallinity persisted despite titanate phase incorporation. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 11–22, 2003     

Synthesis,Characterization and Catalysis of Ce‐MCM‐41

The cerium‐containing MCM‐41 (Ce‐MCM‐41) has been synthesized by direct hydrothermal method. The low‐angle XRD patterns revealed the typical five major peaks of MCM‐41 type hexagonal structures. The interplanar spacing d₁₀₀ = 38.4 Å was obtained that can be indexed on a hexagonal unit cell parameter with a_o = 44.3 Å which was larger than that of pure siliceous MCM‐41 (Si‐MCM‐41). Transmission electron micrograph shows the regular hexagonal array of uniform channel characteristics of MCM‐41. The BET surface area of Ce‐MCM‐41 was 840 m²/g, which is much reduced as compared to that of Si‐MCM‐41, with the pore size of 26.9 Å and mesopore volume of 0.78 cm³/g were measured by nitrogen adsorption‐desorption isotherm at 77 K. Along with the results, the synthesized Ce‐MCM‐41 exhibited a well‐ordered MCM‐41‐type mesoporous structure with the incorporation of cerium. Using Ce‐MCM‐41 as a support, the Rh (0.5 wt%) catalyst exhibited very high activity for the NO/CO reactions.     

Preparation and properties of silylated PTFE/SiO2 organic–inorganic hybrids via sol–gel process

A study on poly(tetrafluoroethylene) (PTFE) reinforced with tetraethoxysilanes (TEOS) derived SiO₂ is described. It included the manufacturing process of SiO₂‐reinforced PTFE and the effects of silylation agent on the properties of the hybrid material, such as porosity, hydrophobic, thermal resistance, dielectric and mechanical properties, and microstructure. PTFE/SiO₂ hybrids of 50 wt % SiO₂ loading were prepared via a sol–gel process and were shaped by a two‐roll milling machine. Trimethylchlorosilane and hexamethydisilazane were used as the silylation agents. Our results showed that the water absorption and dielectric loss of PTFE/SiO₂ hybrid had significantly improved with silylation agent. The silylation process replaced Si? OH with Si? CH₃ on the surface of the TEOS‐derived silica colloidal particle. The existence of trimethylsilyl [? Si(CH₃)₃] on the surface of the modified PTFE/SiO₂ hybrid was confirmed via infrared and solid‐state ²⁹Si magic‐angle spinning nuclear magnetic resonance spectra. Nitrogen‐sorption techniques were used to characterize the modified and unmodified PTFE/SiO₂ hybrids. The microstructure of SiO₂ in the matrix was also evaluated with scanning electron microscopy and transmission electron microscopy. Our results showed that the silylated sol–gel‐derived PTFE/SiO₂ hybrids had exhibited high porosity (53.7%) with nanosize pores (10–40 nm) and nanosize colloidal particles (20–50 nm). This manifests itself as have the ultralow dielectric properties (D_k = 1.9 and D_f = 0.0021), low coefficient of thermal expansion (66.5 ppm/°C), high tensile modulus (141 MPa), excellent thermal resistance (T_d = 612 °C), and an increased hydrophobia (θ = 114°); moreover, the hydrophobic property of the PTFE/SiO₂ hybrid was thermally stable up to 400 °C. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1789–1807, 2004     

Mesoporous Molecular Sieve MCM‐41 as a Novel and Efficient Catalyst to Synthesis of 2‐Substituted Benzimidazoles

o‐Phenylenediamine derivatives readily react with benzoyl chloride derivatives in the presence of MCM‐41 as catalyst to yield 2‐substituted benzimidazoles in very good yields.     

Facile synthesis of core‐shell organic–inorganic hybrid nanoparticles with amphiphilic polymer shell by one‐step sol–gel reactions

Organic–inorganic hybrid core‐shell nanoparticles with diameters ranging from 100 to 1000 nm were prepared by a one‐pot synthesis based on base catalyzed sol–gel reactions using tetraethoxysilane and a triethoxysilane‐terminated polyethylene‐b‐poly(ethylene glycol) as reactants. Data from TEM, TGA, and solid‐state NMR analysis are in agreement with the formation of core‐shell nanoparticles with an inorganic‐rich core and an external shell consisting of an amphiphilic block copolymer monolayer. The influence of the organic–inorganic ratio, solution concentration, and postcuring temperature on core and shell dimensions of the nanospheres were investigated by TEM microscopy. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1699–1709, 2008     

Preparation of stable second‐order nonlinear optical films by sol–gel technique

A stable nonlinear optical (NLO) film containing “T” type alkoxysilane dye was prepared by sol–gel technology. This crosslinked “T” type alkoxysilane dye was synthesized and fully characterized by FTIR, UV–Vis spectra, and ¹H‐NMR. Followed by hydrolysis and copolymerization processes of the alkoxysilane with γ‐glycidoxypropyl trimethoxysilane (KH560) and tetraethoxysilane (TEOS), high quality inorganic–organic hybrid second‐order NLO films were obtained by spin coating. The “T” type structure of the alkoxysilane was found to be effective for improving the temporal stability of the optical nonlinearity due to the reduction in the relaxation of the chromophore in the film materials. Copyright © 2009 John Wiley & Sons, Ltd.     

Solid‐state lasers based on inorganic–organic hybrid materials obtained by combined sol–gel polymer technology

Sol–gel glass matrices in which organic laser dyes are embedded can be used as the gain medium in solid‐state, continuously tunable lasers. Such lasers are very simple to construct, and potentially very compact and efficient. Unlike the commonly used liquid dye laser systems, solid‐state dye lasers can be made mechanically robust and portable. In this article, the development of sol–gel/dye lasers, including the sol–gel technology, dye properties, and laser operation, is reviewed. In addition, new solid‐state hosts (such as polyurethane/silica ORMOSILs), additional organic dyes (cyanines), and new studies on the stability of the dyes are presented. Copyright © 2004 John Wiley & Sons, Ltd.     

An anhydrous sol–gel system derived from methyldichlorosilane

Pyridine‐catalyzed reactions of methyldichlorosilane with bis(trimethylsilyl)carbodiimide afford a dichlorosilane‐derived anhydrous sol–­gel material. Both trimethylchlorosilane formation and Si–H disproportionation act as crosslinking mechanisms. The dried gels form amorphous or crystalline materials, depending on the sample history. The xerogels gave Si/C/N ceramics when pyrolyzed at 1200 °C. Copyright © 1999 John Wiley & Sons, Ltd.