Topic
Silica gel
About: Silica gel is a research topic. Over the lifetime, 22313 publications have been published within this topic receiving 325516 citations. The topic is also known as: Amorphous silica & Precipitated amorphous silica.
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TL;DR: In this paper, the Bronsted acidic ionic liquid 1-(propyl-3-sulfonate) vinylimidazolium hydrogen sulfate ([(CH2)3SO3HVIm]HSO4) was immobilized on the silica gel using tetraethoxysilane (TEOS) as silica source.
100 citations
TL;DR: Synthesis and characterization of undoped and Mn2+ doped ZnS nanocrystallites (radius 2-3 nm) embedded in a partially densified silica gel matrix are presented in this paper.
Abstract: Synthesis and characterization of undoped and Mn2+ doped ZnS nanocrystallites (radius 2–3 nm) embedded in a partially densified silica gel matrix are presented. Optical transmittance, photoluminescence (PL), ellipsometric and electron spin resonance measurements revealed manifestation of quantum size effect. PL spectra recorded at room temperature revealed broad blue emission signal centred at ∼ 420 nm and Mn2+ related yellow-orange band centred at ∼ 590 nm while ESR indicated that Mn in ZnS was present as dispersed impurity rather than Mn cluster.
99 citations
TL;DR: In this paper, the reaction of epoxides with nitrogen heterocycles such as indoles, pyrroles, imidazoles, and pyrazoles was studied under both high-pressure and silica gel-catalyzed conditions.
Abstract: The reaction of epoxides with nitrogen heterocycles such as indoles, pyrroles, imidazoles, and pyrazoles was studied under both high-pressure and silica gel-catalyzed conditions. Whereas it has been reported that the treatment of indole with styrene oxide at 10 kbar and 42 °C for 24 h gave 2-(3-indolyl)-2-phenylethanol in 56% yield, the same compound was obtained in 88% yield when the reaction was conducted on silica gel at rt for 1 week. Similarly, efficient reaction of epoxides with pyrroles, imidazoles, and pyrazoles was achieved. In terms of stereochemical features, the epoxide ring opening reaction of (R)-(+)-styrene oxide with indole was found to proceed stereoselectively in an SN2 fashion at the benzyl carbon, in either case.
99 citations
TL;DR: The use of a stable solution of ferric chloride for the detection of cholesterol and cholesteryl esters on thin-layer chromatographic layers is described and the levels of sensitivity for the new reagent are shown.
99 citations
TL;DR: Combined Raman and Si NMR investigations of high surface area silica gels indicate that dehydroxylation of the a-SiO{sub 2} surface results preferentially in the formation of cyclic trisiloxanes (3-membered rings) as discussed by the authors.
Abstract: Combined Raman and {sup 29}Si NMR investigations of high surface area silica gels indicate that dehydroxylation of the a-SiO{sub 2} surface results preferentially in the formation of cyclic trisiloxanes (3-membered rings). Estimates of the maximum experimentally observed concentration of 3-membered rings correspond to a surface coverage of about 28-58{percent}. Two consequences of 3-membered rings on the a-SiO{sub 2} surface are enhanced hydrolysis rates and increased skeletal densities. 29 refs., 6 figs.
99 citations