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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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Journal ArticleDOI
TL;DR: The compressive modulus and compressive strain show large enhancements over sPS and silica aerogels indicating synergy, although Type 1 hybrid Aerogels were found to be more robust and showed fast absorption and high absorption capacity for a representative hydrocarbon liquid.
Abstract: A class of inorganic–organic hybrid mesoporous aerogel structure was synthesized by growing gel in a gel. In Type 1, silica gels were grown inside the macropores of thermoreversible syndiotactic polystyrene (sPS) gel, while Type 2 hybrid aerogels were obtained by thermoreversible gelation of sPS chains in the mesopores of preformed silica gel. The hybrid gels were converted into aerogels by exchanging the solvent with liquid carbon dioxide followed by supercritical drying. The hybrid aerogels presented cocontinuous networks of pearl-necklace silica particles and crystalline strands of sPS and exhibited the “petal effect” due to the presence of superhydrophobic sPS and hygroscopic silica. The compressive modulus and compressive strain show large enhancements over sPS and silica aerogels indicating synergy, although Type 1 hybrid aerogels were found to be more robust. The hybrid aerogels showed fast absorption and high absorption capacity for a representative hydrocarbon liquid.

90 citations

Journal ArticleDOI
TL;DR: In this article, an analysis of the effect of metal ions such as Fe2+, Co2+, Ni2+ and CO3 2 -on the performance of the sorbent, gel-amine, under a given column condition was tested.
Abstract: Organic complexing moieties such as amine, 2°-amide and benzamide functional groups were covalently linked to silica gel by performing organomodification on commercially available silica gel. The extraction of uranium as a function of pH, time, concentration of uranium and the effect of ions such as Fe2+, Co2+, Ni2+ and CO3 2- on the distribution coefficient of uranium by sorbent was studied. The data was fitted into Langmuir adsorption isotherm. The selectivity of the sorbents towards uranium were found to decrease in the order gel-amine >> gel-benzamide ≅ gel-2°-amide at all pHs. The presence of metal ions such as Fe2+, Co2+, Ni2+ and CO3 2- were found to decrease the distribution coefficients (K d, ml/g) of uranium and the decrease was very high when Fe2+ was present. The performance of the sorbent, gel-amine, under a given column condition was tested by following the breakthrough curve of uranium up to C/C 0 = 0.025. The sorbent was found to be good for the quantitative pre-concentration of uranium from a large amount of sodium.

90 citations

Journal ArticleDOI
TL;DR: An enantiomerically enriched pyrimidyl alkanol with either S or R configurations was obtained stochastically from the reaction between pyrimidine-5-carbaldehyde and diisopropylzinc in the presence of achiral silica gel in conjunction with asymmetric autocatalysis with amplification of chirality.

90 citations

Journal ArticleDOI
TL;DR: In this article, 3,4-Dihydropyrimidin-2(1H)-ones derivatives were synthesized in moderate to high yields in one-pot three component reaction from the corresponding aldehydes, ketones or 1,3-dicarbonyl compounds and urea.
Abstract: 3,4-Dihydropyrimidin-2(1H)-ones derivatives were synthesized in moderate to high yields in one-pot three component reaction from the corresponding aldehydes, ketones or 1,3-dicarbonyl compounds and urea, in the presence of catalytic amount of KAl(SO4)2·12H2O (Alum) supported on silica gel (Alum-SiO2) as a non-toxic, reusable, inexpensive and easily available reagent, under solvent-free conditions at 80 °C. Compared to the classical Biginelli reaction, this new method consistently has the advantage of good yields.

90 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023140
2022274
2021224
2020426
2019772
2018828