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Silica Gel (silica + gel)
Terms modified by Silica Gel Selected AbstractsChemInform Abstract: Al(HSO4)3/Silica Gel as a Novel Catalytic System for the Ring Opening of Epoxides with Thiocyanate Anion under Solvent-Free Conditions.CHEMINFORM, Issue 26 2010Ali Reza Kiasat Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Stripping Voltammetry of Cerium(IIl) with a Chemically Modified Carbon Paste Electrode Containing Functionalized Nanoporous Silica GelELECTROANALYSIS, Issue 2 2008Mehran Javanbakht Abstract This research introduces the design of an adsorptive stripping voltammetric method for the cerium(III) determination at a carbon paste electrode, chemically modified with dipyridyl-functionalized nanoporous silica gel (DPNSG-CPE). The electroanalytical procedure comprised two steps: the Ce(III) chemical accumulation at ,200,mV followed by the electrochemical detection of the Ce(III)/dipyridyl complex, using anodic stripping voltammetry. The factors, influencing the adsorptive stripping performance, were optimized including the modifier quantity in the paste, the electrolyte concentrations, the solution pH and the accumulation potential or time. The resulting electrode demonstrated a linear response over a wide range of Ce(III) concentration (1.0,28,ng mL,1). The precision for seven determinations of 4 and 10,ng mL,1 Ce(III) was 3.2% and 2.5% (relative standard deviation), respectively. The prepared electrode was used for the cerium determination in real samples and very good recovery results were obtained. [source] Inorganic Precipitated Silica Gel.CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2010Gel Properties, Part 1: Gelation Kinetics Abstract Precipitated silica (SiO2) is industrially produced by mixing a silicate solution with acid in a semi-batch process. Polycondensation of monomeric silica leads to the formation of particles which aggregate and eventually form a particulate gel. However, this is instantly fragmented by the mechanical energy input caused by the stirrer. Shrinkage and compaction of these fragments lead to the final product aggregates. It is the aim of this study to enable tailoring of the structure and size of these product particles via the process parameters. The present paper describes the influence of the parameters temperature, ionic strength, and composition, which affect the pH, on the properties of unstirred gels regarding their elasticity and thus their fragmentation behavior. Gelation time may be qualitatively estimated solely from the concentration of the feed materials. [source] ChemInform Abstract: A Mild and Convenient One-Pot Two-Step Synthesis of Hydroxyiminodihydrobenzofurans Mediated by Silica Gel under Microwave Activation Conditions.CHEMINFORM, Issue 39 2010Deepak Kumar Barange Abstract Cyclic 1,3-dicarbonyl compounds (I) react with various nitroolefins to furnish the title products exclusively or predominantly as (E)-isomers. [source] ChemInform Abstract: A Novel Three-Component Reaction of a Secondary Amine and a 2-Hydroxybenzaldehyde Derivative with an Isocyanide in the Presence of Silica Gel: An Efficient One-Pot Synthesis of Benzo[b]furan Derivatives.CHEMINFORM, Issue 2 2010Ali Ramazani Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Oxidation of Hantzsch 1,4-Dihydropyridines Using Supported Nitric Acid on Silica Gel and Poly Vinyl Pyrrolidone (PVP) under Mild and Heterogeneous Conditions.CHEMINFORM, Issue 37 2009Arash Ghorbani-Choghamarani Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Preparation of Diphenyl Phosphide and Substituted Phosphines Using Alkali Metal in Silica Gel (M,SG).CHEMINFORM, Issue 36 2009Partha Nandi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Efficient Method for Oxidation of Ketones to Esters with 4-Aminoperoxybenzoic Acid Supported on Silica Gel.CHEMINFORM, Issue 45 2008Dadkhoda Ghazanfari Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: An Efficient Synthesis of Propargylamines Using a Silica Gel Anchored Copper Chloride Catalyst in an Aqueous Medium.CHEMINFORM, Issue 7 2008B. Sreedhar Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Covalently Anchored Sulfonic Acid on Silica Gel as an Efficient and Reusable Heterogeneous Catalyst for the One-Pot Synthesis of Hantzsch 1,4-Dihydropyridines under Solvent-Free Conditions.CHEMINFORM, Issue 7 2008Raman Gupta Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Perchloric Acid Adsorbed on Silica Gel (HClO4,SiO2) as an Inexpensive, Extremely Efficient, and Reusable Dual Catalyst System for Acetal/Ketal Formation and Their Deprotection to Aldehydes/Ketones.CHEMINFORM, Issue 20 2007Raj Kumar Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Ionic Liquid Functionalized Silica Gel: Novel Catalyst and Fixed Solvent.CHEMINFORM, Issue 2 2007Guoqiao Lai Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Perchloric Acid Impregnated on Silica Gel (HClO4/SiO2): A Versatile Catalyst for Michael Addition of Thiols to the Electron-Deficient Alkenes.CHEMINFORM, Issue 33 2006Abu T. Khan Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] An Efficient Oxidation of 1,4-Dihydropyridines to Pyridines Using Silver Carbonate on Silica Gel and Celite.CHEMINFORM, Issue 32 2006Ahmad Reza Momeni Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Silica Gel Promoted Synthesis of 3,4,5-Triaryltetrahydro-1,4-thiazine Derivatives from ,,,,-Dichloro Sulfides and Aromatic Amines.CHEMINFORM, Issue 8 2006Masatoshi Mihara Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access the actual ChemInform Abstract, please click on HTML or PDF. [source] Nitric Acid in the Presence of Supported P2O5 on Silica Gel: An Efficient and Novel Reagent for Oxidation of Sulfides to the Corresponding Sulfoxides.CHEMINFORM, Issue 48 2005Abdol R. Hajipour Abstract For Abstract see ChemInform Abstract in Full Text. [source] An Intriguing Effect of Lithium Perchlorate Dispersed on Silica Gel in the Bromination of Aromatic Compounds by N-Bromosuccinimide.CHEMINFORM, Issue 38 2005Mojtaba Bagheri Abstract For Abstract see ChemInform Abstract in Full Text. [source] Selective Oxidation of Aryl Ketones to ,-Diketones with 4-Aminoperoxybenzoic Acid Supported on Silica Gel in the Presence of Air.CHEMINFORM, Issue 11 2005Dadkhoda Ghazanfari Abstract For Abstract see ChemInform Abstract in Full Text. [source] Direct Oxidative Deprotection of Tetrahydropyranyl Ethers Using Hexamethylenetetramine-Bromine Supported onto Silica Gel under Microwave Irradiation in Solventless System.CHEMINFORM, Issue 52 2004Mahboobeh Behnam Dehkordi No abstract is available for this article. [source] Microwave-Assisted N-Alkylation of Potassium Phthalimide and Potassium Succinimide onto Silica Gel in Dry Media.CHEMINFORM, Issue 49 2004R. Hekmatshoar No abstract is available for this article. [source] One-Pot Synthesis of Tetra-Substituted Imidazoles on Silica Gel under Microwave Irradiation.CHEMINFORM, Issue 21 2004Yu Xu Abstract For Abstract see ChemInform Abstract in Full Text. [source] SiBr4/Wet Silica Gel as an Efficient Heterogeneous System for Cleavage of C=N.CHEMINFORM, Issue 12 2004Surya Kanta De Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: C-Vinylation of 1-Vinylpyrroles with Benzoylacetylene on Silica Gel.CHEMINFORM, Issue 6 2002Boris A. Trofimov Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Sinus Lift Using a Nanocrystalline Hydroxyapatite Silica Gel in Severely Resorbed Maxillae: Histological Preliminary StudyCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 2009Luigi Canullo DDS ABSTRACT Purpose: The aim of this preliminary study was to evaluate histologically a nanocrystalline hydroxyapatite silica gel in maxillary sinus floor grafting in severely resorbed maxillae. Materials and Methods: A total of 16 consecutive patients scheduled for sinus lift were recruited during this study. Patients were randomly divided in two groups, eight patients each. In both groups, preoperative residual bone level ranged between 1 and 3 mm (mean value of 2.03 mm). No membrane was used to occlude the buccal window. Second surgery was carried out after a healing period of 3 months in Group 1 and 6 months in Group 2. Using a trephine bur, one bone specimen was harvested from each augmented sinus and underwent histological and histomorphometric analysis. Results: Histological analysis showed significant new bone formation and remodeling of the grafted material. In the cores obtained at 6 months, regenerated bone, residual NanoBone, and bone marrow occupied respectively 48 ± 4.63%, 28 ± 5.33%, and 24 ± 7.23% of the grafted volume. In the specimens taken 3 months after grafting, mean new bone was 8 ± 3.34%, mean NanoBone was 45 ± 5.10%, and mean bone marrow was 47 ± 6.81% of the bioptical volume. Conclusions: Within the limits of this preliminary prospective study, it was concluded that grafting of maxillary sinus using nanostructured hydroxyapatite silica gel as only bone filler is a reliable procedure also in critical anatomic conditions and after early healing period. [source] Synthesis of Sugar-Based Silica Gels by Copper-Catalysed Azide,Alkyne Cycloaddition via a Single-Step Azido-Activated Silica Intermediate and the Use of the Gels in Hydrophilic Interaction ChromatographyCHEMISTRY - A EUROPEAN JOURNAL, Issue 19 2010Lisa Moni Dr. Abstract Novel sugar-based silica gels were prepared by exploiting the copper-catalysed azide,alkyne cycloaddition (CuAAC) of two different sugar alkynes, namely, ethynyl C -galactoside 1 and propargyl O -lactoside 2, with new single-step azido-activated silica gels. The fully characterised stationary phases were generally used for hydrophilic interaction chromatography (HILIC), with particular application in the stereoselective separation of monosaccharides. Dynamic HILIC (DHILIC) experiments were performed to evaluate the influence of mutarotation on the chromatographic peak shapes of two interconverting sugar anomers. The potential of such materials was shown in the separation of other highly polar compounds, including amino acids and flavonoids. [source] Growth and characterization of strontium tartrate pentahydrate crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2008A. Firdous Abstract Silica gel impregnated with L-tartaric acid and using strontium nitrate as the second reactant leads to the growth of well faceted strontium tartrate pentahydrate single crystals. The morphological developmen and internal cell dimensions are observed to be different from the ones reported in the literature for strontium tartrate trihydrate crystals. The crystals are characterized using XRD, CH analysis, SEM, FTIR spectroscopy and thermoanalytical techniques. The crystals are observed to be thermally stable upto about 105°C but thereafter start decomposing and ejecting water of hydration at various stages, finally reducing to strontium oxide. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Bioactivity, pre-osteoblastic cell responses, and osteoconductivity evaluations of the electrospun non-woven SiO2,CaO gel fabricsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2009Yang-Jo Seol Abstract The evaluations of the fibers characteristics, bioactivity, pre-osteoblastic cell responses, and osteoconductivity of the non-woven SiO2,CaO gel fabric made by electrospinning method was carried out. Silica gels with four different calcium contents were prepared by condensation following hydrolysis of tetraethyl orthosilicate under acidic conditions. The molar ratios of Ca to Si prepared ranged from 0 to 0.15. SiO2,CaO gel fabrics were heat-treated at 300°C for 3 h after spinning under an electric field of 2 kV/cm. As the Ca to Si ratio increased, the diameter of electrospun SiO2,CaO gel fibers increased because the viscosity of the SiO2,CaO gel solution increased. The apatite-forming ability of heat-treated, non-woven SiO2,CaO gel fabric was evaluated in simulated body fluid and tended to increase with an increasing Ca to Si molar ratio. However, proliferation and differentiation tended to decrease with an increasing Ca to Si molar ratio. The sample which had the Ca to Si ratio as 0.10 showed good osteoconductivity in vivo in the calvarial defect New Zealand white rabbit model compared to that had the Ca to Si ratio as 0 and empty defect. These results strongly suggest that non-woven SiO2,CaO gel fabric made by the electrospinning method has potential for application as a bone grafting material. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] Preparation and properties of polyhedral oligomeric silsesquioxane,polysiloxane copolymersAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 8 2010Takahiro Gunji Abstract All siloxane-type siloxane,polyhedral oligomeric silsesquioxane [(HSiO3/2)8, T8H] copolymers were synthesized by the dehydrogenative condensation of T8H with diphenylsilanediol, tetraphenyldisiloxane-1,3-diol or silanol-terminated polydimethylsiloxanes in the presence of diethylhydroxylamine followed by trimethylsilylation. Coating films were prepared by spin-coating of the coating solutions prepared from the dehydrogenative condensation products. The hardness of the coating films was evaluated by a pencil hardness test and was found to increase up to 6H with increases in the curing temperature. Silica gels were prepared by concentrating the coating solution following by pyrolysis. These silica gels showed a specific surface area 449 m2/g at 650 °C corresponding to the formation of a silica network in response to combustion of the phenyl groups. Copyright © 2009 John Wiley & Sons, Ltd. [source] Characterization of pure and doped potassium hydrogen tartrate single crystals grown in silica gelCRYSTAL RESEARCH AND TECHNOLOGY, Issue 5 2009I. Quasim Abstract Growth of pure-, sodium- and lithium- doped potassium hydrogen tartrate single crystals by gel technique is reported. Growth conditions conducive for the growth of single crystals are worked out. The crystals are characterized by using powder XRD, SEM, FTIR, AES, EDAX, CH analysis and thermoanalytical techniques. The stoichiometric composition for the grown crystals are established as KHC4H4O6.H2O, (K)0.98(Na)0.02.H2O and (K)0.94(Li)0.06HC4H4O6.H2O. Doping of sodium and lithium in the pure potassium hydrogen tartrate single crystals is found to influence the size, perfection, morphology, crystal structure and the thermal stability of crystals. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] XRD, thermal, FTIR and SEM studies on gel grown ,-glycine crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2007E. Ramachandran Abstract Glycine is the smallest among amino acids. The polymorphs, ,- and ,-forms of glycine were crystallized in silica gel by reduction of solubility method. The grown crystals were characterized by single crystal X-ray diffraction studies and density determination. Fourier transform infrared spectroscopic studies and thermogravimetric analysis of ,-glycine were also conducted. Morphological and scanning electron microscopic (SEM) studies were also made and compared with the crystal packing. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||||||||||||||||||||||||||||||||