Herein, we report the preparation of small and narrowly distributed (2.1 ± 0.5 nm) Ag nanoparticles supported on passivated silica, where the surface OH groups are replaced by OSiMe3 functionalities. This synthetic method involves the grafting of silver(I) bis(trimethylsilyl)amide ([AgN(SiMe3)2]4) on silica partially dehydroxylated at 700 °C, followed by a thermal treatment of the grafted compl...

effluent from ro (reverse osmosis) systems during recovery gradually becomes concentrated and supersaturated with soluble salts such as calcium carbonate (caco3), calcium sulfate (caso4), barium sulfate (baso4) and silica (sio2). thus we were looking for procedures to prevent precipitation of soluble salts on the membrane surface and decrease membrane permeability. therefore, recovery could be ...

Silica Vanadic Acid, SVA, (oxo-vanadium has been supported on silica) as a dual Lewis and Bronsted acid ability was prepared and efficiently catalyzed one-pot multi-component condensation of enolizable ketones or alkyl acetoacetates with aromatic aldehydes, acetonitrile and acetyl chloride. The described reaction was produced β-acetamido ketone or ester derivatives in high to excellent yields i...

The present study examined the effect of three methods of preparation on the properties and catalytic performance of Cu-Mn/SiO2 catalysts for the water gas shift reaction (WGSR). Impregnation and coprecipitation and the new approach of thermal decomposition of [Cu(H2O)6][Mn(dipic)2].2H2O/SiO2 inorganic precursor complex were used for the synthesis of the silica-supported copper-manganese mixed ...

ethylene polymerization was carried out using phillips chromium catalyst based on silica supports such as silicaaerogel, sio2 (grace 643), and titanium modified sio2 (g 643), and the results were compared with othercatalysts based on sio2 (aldrich), sba-15(hex), sba-15(sp) and mcm-41. a combination of tga, dsc, xrd,nitrogen adsorption, sem, icp, ftir and other analyses were used to characterize...

Silica Vanadic Acid, SVA, (oxo-vanadium has been supported on silica) as a dual Lewis and Bronsted acid ability was prepared and efficiently catalyzed one-pot multi-component condensation of enolizable ketones or alkyl acetoacetates with aromatic aldehydes, acetonitrile and acetyl chloride. The described reaction was produced β-acetamido ketone or ester derivatives in high to excellent yields i...

In this study, silica coated Au nanospheres (Au@SiO2) were prepared by a reverse microemulsion method; subsequently, a layer of fluorescent quantum dots (QDs) were adsorbed onto it and then it was coated with silica again. After modifying with PVP, the composite silica coated gold nanosphere and quantum dots nanoparticle (Au@SiO2-QDs/SiO2-PVP) was obtained. This composite structure contained Au...

In the present work, we have developed an efficient catalytic procedure for the chemo-selective acetylation of various substrates like amines, phenols and alcohols into their corresponding acetylated products using acetyl chloride in the presence of catalytic amount of metal acetylacetonates covalently anchored onto amine functionalized silica under solvent-free conditions. The catalysts were c...

A unique and rational design was presented to fabricate Ni/SiO2@Au magnetic hollow microspheres (MHMs) with interesting structures and well-dispersed metal nanoparticles. Hierarchical nickel silicate hollow microspheres were synthesized using silica colloidal spheres as a chemical template. Then, Ni/SiO2 MHMs with well-dispersed Ni nanoparticles were prepared via an in situ reduction approach. ...

When using X-ray fluorescence spectrometry for the determination of alkali and alkaline earth metals in a silica matrix, frequent recalibration with reference samples is necessary. Determination of metals in these reference samples is carried out using classical analysis. The latter was not possible with barium and strontium in the presence of each other owing to mutual interference. Isotachoph...