硅胶固载酸功能化离子液体催化剂的制备和应用

将带有酸官能团的离子液体固载到具有高表面积的硅胶上,制备的硅胶固载酸功能化离子液体可作为催化剂用于多种有机反应。该新型催化剂具有高效、高选择性、离子液体用量少、产品易分离和催化剂易回收等优点,因有望用于化工过程的固定床反应器而受到关注。     

硅材料固载离子液体挂载金属催化剂应用研究进展

离子液体具有独特的性质,将具有高表面积的硅材料用离子液体进行改性,再挂载金属化合物,可制得集离子液体中均相催化和固体非均相催化体系于一身的新型催化剂,用于多种有机反应.这些催化剂具有高效、高选择性、离子液体用量少、产品易分离和催化剂易回收等优点,因有望用于化工过程的固定床反应器而受到关注.本文综述了2005年以来硅材料固载离子液体挂载金属催化剂的应用研究成果.     

Solid-phase extraction method for preconcentration of trace amounts of some metal ions in environmental samples using silica gel modified by 2,4,6-trimorpholino-1,3,5-triazin

A method was proposed for the preconcentration of some transition elements at trace levels using a column packed with silica gel modified by a synthetic ligand. Metal ions were adsorbed on 2,4,6-trimorpholino-1,3,5-triazin modified silica gel, then analytes retained on the adsorbent were eluted by 1 mol L⁻¹ hydrochloric acid and determined by flame atomic absorption spectrometry (FAAS). The influences of some experimental parameters including pH of the sample solution, weight of adsorbent, type, concentration and volume of eluent, flow rates of the sample solution and eluent, and sample volume on the preconcentration efficiency have been investigated. The influences of some matrix elements were also examined. The method also was used for simultaneous preconcentration of these elements and the method was successfully applied to the preconcentration and determination of them. The detection limits of the method for Ni²⁺, Co²⁺, Cd²⁺ and Zn²⁺were 0.29, 0.20, 0.23 and, 0.30 ng mL⁻¹, respectively. The application of this modified silica gel to preconcentration of investigated cation from tap water, lake water, urine and apple leaves gave high accuracy and precision (relative standard deviation (R.S.D.) <3%).     

Development of cloud point extraction for simultaneous extraction and determination of gold and palladium using ICP-OES

Cloud point method was applied for the simultaneous extraction and preconcentration of trace amounts of gold and palladium. The extraction of analytes was performed in the presence of 1,8-diamino-4,5-dihydroxy anthraquinone as chelating agent and Triton X-114 as a non-ionic surfactant. After phase separation, the surfactant-rich phase was diluted with concentrated HNO(3) (65%, w/w) and the analytes concentrations were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). The variables affecting the complexation and extraction conditions were optimized and under the optimum conditions (i.e. pH 6.5, 2.2 x 10(-4) mol l(-1) chelating agent, 0.15% (w/v) of Triton X-114, equilibration temperature 55 degrees C, centrifuge at 3500 rpm), quantitative extraction of Au(III) and Pd(II) from 100 ml of the aqueous solution was performed. The calibration curves were linear in the range of 0.5-1000 microg l(-1) with detection limits of 0.5 and 0.3 microg l(-1) and the enrichment factors were 8.6 and 20.2 for Au and Pd, respectively. Also the precision (%RSD) for eight replicate determinations of the analytes was better than 5%. Finally, the proposed method was successfully applied for the determination of Au and Pd in mine stones and standard reference materials (SRM).     

MALDI-TOF MS of phosphorylated lipids in biological fluids using immobilized metal affinity chromatography and a solid ionic crystal matrix

When targeting a certain class of analytes, such as the phosphorylated lipids in complex biological extracts, interfering species can pose challenges to qualitative and quantitative analyses. Two aspects of lipid analysis were optimized to simplify the isolation and characterization of phosphorylated lipids in biological extracts. A new solid ionic crystal MALDI matrix was synthesized which combined the lipid response enhancing UV-absorber p-nitroaniline with the protonating agent butyric acid. Mass spectra of the extracts containing phosphorylated lipids were simplified by revealing only protonated molecules [M + H]+ of the zwitterionic phosphatidylcholine (PC) headgroup-containing lipids, such as lyso-PC, PC, and platelet-activating factor. For the anionic phosphorylated lipids, such as phosphatidylglycerol, phosphatidic acid, and phosphatidylserine, further spectrum simplification is obtained by the appearance of only the monosodium adducts [M + Na]+ as the major molecular ions, in preference to the double sodium adducts [M + 2Na - H]+. In addition, a new extraction, isolation, and cleanup procedure has been developed to prepare the phosphorylated lipids for MALDI-TOF analysis by the use of immobilized metal ion affinity chromatography media (i.e., ZipTip). The latter procedure was successfully applied to a complex biological tear film lipid layer extract in preparation for MALDI-TOF analysis and phospholipid characterization.     

Preparation, characterization and photocatalytic activity of manganese doped TiO(2) immobilized on silica gel

A series of Mn-TiO(2)/SiO(2) (silica gel loaded with manganese doped TiO(2)) photocatalysts have been prepared by sol-gel method, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Photocatalytic activities were enhanced in photocatalytic degradation of methyl orange over Mn-TiO(2)/SiO(2). XPS analysis shows that a Ti-O-Si or Ti-O-Mn bond is formed on the surface of photocatalyst. Mn is doped as a mixture of Mn(2+) and Mn(3+) on the surface of 1.0mol% Mn-TiO(2)/SiO(2). Mn(3+) appears to trap electrons and prohibit the electron-hole recombination. The electrons trapped in Mn(3+) site are subsequently transferred to the adsorbed O(2). As a result, the combination of the electron-hole pair was reduced.     

手性配体交换乳状液膜选择性萃取扁桃酸对映体

基于手性配体交换反应,研究了在含有N-n-十二烷基-L-羟基脯氨酸和铜离子的配合物为手性配体的乳状液膜体系中选择性萃取扁桃酸对映体.考察了扁桃酸外消旋体浓度,手性萃取方向,有机溶剂和表面活性剂配比,从外水相到内水相pH值的梯度变化以及外水相的pH值变化对选择性萃取性能的影响,从而确定了合适的选择性萃取条件.     

Wood-plastic composites based on HDPE and ionic liquid additives

The improvement of wood-plastic composites properties by additives and compatibilizers is a critical issue to produce value-added materials. High-density polyethylene-wood composites have been obtained through compression molding at 140 °C, using two types of additives, namely methyltrioctylammonium bis (trifluoromethylsulfonyl)imide and trihexyltetradecylphosphonium bis (2,4,4-trimethylpentyl) phosphinate room temperature ionic liquids. The ionic liquids improve the interfacial adhesion between the wood and the polymer phases, contributing to an increased stability of the material to water action and to an improved impact resistance and tensile strength in comparison with the reference. Also, the FTIR spectroscopy tests have proven a higher resistance of the ionic liquid-containing composites to accelerated photooxidation. Preliminary screening tests have also proven the antifungal character of the ionic liquids used in this study against brown rot (Postia placenta). This study opens new insights in the domain of polymeric composite materials, through documenting the possibility of blending new types of chemically distinct materials, difficult to be achieved by traditional functionalization/derivatization routes.     

A solid-state dye-sensitized solar cell based on a novel ionic liquid gel and ZnO nanoparticles on a flexible polymer substrate

This paper describes a new strategy to make a full solid-state, flexible, dye-sensitized solar cell (DSSC) based on novel ionic liquid gel, organic dye, ZnO nanoparticles and carbon nanotube (CNT) thin film stamped onto a polyethylene terephthalate (PET) substrate. The CNTs serve both as the charge collector and as scaffolds for the growth of ZnO nanoparticles, where the black dye molecules are anchored. It opens up the possibility of developing a continuous roll to roll processing for THE mass production of DSSCs.     

Growth of noble metal nanostructures on the Bi nanoline surface: A first-principles study

Recent experiments suggest that self-assembled Bi nanolines on the passivated Si(0 0 1) surface can be used as templates to grow one-dimensional arrays of noble-metal (Au, Ag) nanoclusters. In order to ascertain this template effect, the gold atom on the H-terminated Si(0 0 1) surface and that on the Bi line are examined by density-functional methods. The calculation indicates that the gold atom enters a Si dimer on the H-terminated surface and the BiSi backbonds of a Bi dimer on the Bi line. The gold atom is 0.6 eV more stable on the Bi line than on the H-terminated surface. This result suggests the preferential adsorption of gold on the Bi line and confirms its template effect.     

3D face detection based on salient features extraction and skin colour detection using data mining

Face detection has an essential role in many applications. In this paper, we propose an efficient and robust method for face detection on a 3D point cloud represented by a weighted graph. This method classifies graph vertices as skin and non-skin regions based on a data mining predictive model. Then, the saliency degree of vertices is computed to identify the possible candidate face features. Finally, the matching between non-skin regions representing eyes, mouth and eyebrows and salient regions is done by detecting collisions between polytopes, representing these two regions. This method extracts faces from situations where pose variation and change of expressions can be found. The robustness is showed through different experimental results. Moreover, we study the stability of our method according to noise. Furthermore, we show that our method deals with 2D images.     

Adsorption and thermochemical data of divalent cations onto silica gel surface modified with humic acid at solid/liquid interface

Humic acid immobilized onto silica gel surface was studied by the calorimetric titration of divalent cations in aqueous solution. The adsorption isotherms were obtained by the batchwise method and were fitted to a modified Langmuir equation. The maximum number of moles per gram of the material gave: 10.42 ± 0.75, 13.16 ± 0.58, 7.87 ± 0.58 for copper, nickel and zinc, respectively. Gibbs free energies were negative for all systems and the adsorption interactions calorimetrically followed presented endothermic enthalpic values: 6.24 ± 0.47, 6.75 ± 0.74, 6.97 ± 0.58 kJ mol⁻¹ for the same sequence of divalent cations. All liquid/solid interface adsorptions were entropically driven.     

Synthesis and characterization of poly(ionic liquid)-grafted silica hybrid materials through surface radical chain-transfer polymerization and aqueous anion-exchange

Poly(ionic liquid)-grafted silica materials were firstly synthesized by polymerization of 1-vinyl-3-butylimidazolium bromide as a new ionic liquid monomer on mercaptopropylated silica by surface radical chain-transfer polymerization. The bromide counterion was exchanged with three other inorganic anions including tetrafluoroborate, hexafluorophosphate, and trifuoromethanesulfonate through simple aqueous anion-exchange reaction. The obtained poly(ionic liquid)-grafted silica materials were characterized by elemental analysis, infrared spectra, thermogravimetric analysis, and X-ray fluorescence. The wettabilities of the materials with different counterions were verified by static water contact angle measurement. This kind of new materials may have some potential in applied fields such as used as a catalyst, an extractant, a chromatographic stationary phase, etc.     

Selective and quantitative detection of influenza virus proteins in commercial vaccines using two-dimensional high-performance liquid chromatography and fluorescence detection

In this work, we report on the applicability of two-dimensional high-performance liquid chromatography (2D-HPLC) for the comprehensive characterization of inactivated influenza vaccine proteins. This novel procedure features minimal sample treatment and combines the on-line coupling of size exclusion HPLC to reversed-phase HPLC. A comparative analysis of commercial vaccines from three different manufacturers showed the method to be highly selective by providing characteristic reproducible chromatographic profiles for each vaccine. In addition, the method provided enhanced sensitivity for most constituents as a result of the use of native fluorescence detection in the reversed-phase HPLC step. The limits of detection (at a signal-to-noise ratio of >3) for hemagglutinin (HA) antigens were 105 and 172 ng/mL for influenza A/New Caledonia/20/99 and B/Jiangsu/10/2003 strains, respectively. The potential of this 2D-HPLC procedure in terms of quantitative antigen analysis was assessed by determination of the HA content of commercial vaccines. Results provided very good correlation with nominal HA values. The reproducibility (RSD) of the whole procedure was also evaluated and was found to be better than 2 and 3% for calculated antigen concentrations expressed as micrograms of HA per milliliter in commercial vaccines for samples of the same lot (n = 5) or different lots (n = 3), respectively. In addition, it allowed the selective detection of several influenza constituents including nucleoproteins from type A and B viruses and the highly hydrophobic matrix protein 1 from both virus strains.     

Encapsulation of Pd complex in ionic liquid on highly ordered mesoporous silica MCM-41

Palladium acetate was encapsulated onto highly ordered mesoporous silica MCM-41 with the aid of ionic liquid. The immobilized Pd complex can efficiently catalyze Heck coupling reactions of activated and non-activated aryl halides with acrylates. The Pd catalyst exhibited remarkably high catalytic activity and outstanding stability. Moreover, the immobilized palladium acetate could be recycled at least six times without significant loss of activity.     

Aluminium oxide grafted on silica gel surface: Study of the thermal stability, structure and surface acidity

The synthesis of aluminium oxide grafted on silica gel surface was carried out by the reaction of a suitable aluminium precursor with the surface hydroxyl groups, SiOH, of the oxide support in non-aqueous solvent. The advantage of this preparation method, compared to the conventional ones (impregnation or precipitation and calcination), is that the oxide is highly dispersed on the surface (monolayer or submonolayer). The resulting material, SiO₂/Al₂O₃, was heat treated at temperature range of 423 to 1573 K. The Al/Si atomic ratios, determined by X-ray photoelectron spectroscopy (XPS), showed that aluminium is less mobile up to heat treatment of 1173 K and above this temperature part of it diffuses to the interior of the matrix. ²⁷Al solid state nuclear magnetic resonance spectroscopy (NMR) showed two different environments, tetrahedral and octahedral for sample calcined up to 1023 K and above this temperature, aluminium in a trigonal bipyramidal environment was also detected. Pyridine adsorbed on a Lewis acid sites were observed for samples calcined up to 1023 K, and above this temperature they were not detected.     

Potentiometric detection of silver (I) ion based on carbon paste electrode modified with diazo-thiophenol-functionalized nanoporous silica gel

For the first time, triazene compound functionalized silica gel was incorporated into carbon paste electrode for the potentiometric detection of silver (I) ion. A novel diazo-thiophenol-functionalized silica gel (DTPSG) was synthesized, and the presence of DTPSG acted as not only a paste binder, but also a reactive material. The electrode with optimum composition, exhibited an excellent Nernstian response to Ag⁺ ion ranging from 1.0 × 10^? 6 to 1.0 × 10^? 1 M with a detection limit of 9.5 × 10^? 7 M and a slope of 60.4 ± 0.2 mV dec^? 1 over a wide pH range (4.0–9.0) with a fast response time (50 s) at 25 °C. The electrode also showed a long-time stability, high selectivity and reproducibility. The response mechanism of the proposed electrode was investigated by using AC impedance. Moreover, the electrode was successfully applied for the determination of silver ions in radiology films, and for potentiometric titration of the mixture solution of Cl^? and Br^? ions.