Five different silica gels containing two chiral ferrocenyl ligands were prepared by various synthetic routes and tested in an enantioselective Pd(0)-catalyzed allylic substitution and Rh-catalyzed hydrogenation. All the prepared anchored ligands were characterized by porosimetry data, DRIFTS spectra, thermal data and AAS. The aim of the work was to compare the influence of the carrier, surface...

Tetraethoxy orthosilicate (TEOS) was used not only as a precursor of silica, but also as an agent which reinforces the skeleton of silica-gel to prepare an aerogel and resultant silica and silica-alumina with large pore size and pore volume. In this gel skeletal reinforcement, the strength of silica aerogel skeleton was enhanced by aging with TEOS/2-propanol mixed solution to prevent the shrink...

H and C nuclear magnetic resonance (NMR) spectra were recorded at 400 MHz on a Bruker ARX-400 NMR spectrometer (Germany) with tetramethylsilane as internal standard. Column chromatography was performed using Merck (Germany) silica gel (230-400 mesh). Thin layer chromatography (TLC) was performed using Merck silica gel GF254, 0.25 mm thickness. For visualization, TLC plates were placed under aci...

As a liquid moves in the nanopores of a silica gel, because of the hysteresis of sorption behavior, significant energy dissipation can take place. Through a calometric measurement, the characteristics of associated heat generation are investigated. The temperature variation increases with the mass of silica gel, which consists of a reversible part and an irreversible part. The residual temperat...

with 300 ml of ^2-hexane. The water-alcohol fraction was extracted twice with 300ml of CH2C12and the active CH2C12 extracts concentrated to yield 600mg. The extract was chromatographed on a silica gel column using hexane EtOAcas eluting solvent. Fractions with antitumor activity (280 mg) were eluted with w-hexane EtOAc 75 : 25. Column chromatography on silica gel was repeated and the activity (...

series (11) will present the synthesis chemistry of silica sols Silica-based microporous membranes can be successfully proto make unsupported membranes with predictable pore size/ cessed by sol–gel techniques. However tailor making of such memporosity. This article aims to give a detailed account of small branes is still not possible because of the unavailability of systemangle X-ray scattering...

Silica monolith aerogels with different degrees of hydrophobicity by incorporating methyltrimethoxysilane (MTMS) or trimethylethoxysilane (TMES) in standard sol-gel synthesis were prepared. Excellent properties of the aerogels, obtained with the sol-gel synthesis, were preserved with supercritical drying with CO2. The degree of the hydrophobicity of the aerogels was tested by measuring the cont...

CL307-24, a complex of new antibiotics has been isolated from the fermentation broth of Saccharopolyspora aurantiaca sp. nov. The complex was purified by cation-exchange and hydrophobic interaction chromatographies. It was then resolved as one major and three minor components by silica gel chromatography and HPLC.

in this work, the effect of immobilization of bread yeast (saccharomyces cerevisiae) by sol-gel technique combined with functionalized nanoporous silica was investigated in different weight ratios of silica containing materials (tmos: lus-1). the activities of immobilized yeast in days after immobilization were examined. the results showed immobilization maintain the yeast life for a longer tim...

An one-step, fast and potential low cost process has been developed to fabricate silica like glass nanostructures by combining sol-gel chemistry and thermal nanoimprint. An inorganic-organic sol-gel thin film is patterned at low pressure and temperature with flexible stamps. Various geometries are achieved with a patterning resolution of about 150 nm and patterns aspect ratio higher than 4. To ...