نتایج جستجو برای: silica supported
تعداد نتایج: 229959 فیلتر نتایج به سال:
manganese and cobalt salts of para-amino-benzoic acid supported on silica gel as oxidizing catalysts
para-aminobenzoic acid is supported on silica gel via reaction of activated silica gel and p-aminobenzoic acid which is then converted to its manganese and cobalt salts. a mixture of the manganese and cobalt salts of the acid is used to catalyze allylic and benzylic alcohols to their corresponding carbonyl compounds in reasonable yields using oxygen or air. reactions are clean and the catalysts...
A polyethylenimine-impregnated hierarchical silica monolith exhibited significantly higher CO(2) capturing capacity than other silica-supported amine sorbents, and produced a reversible and durable sorption performance.
Recent debates over the active site structure of supported vanadia/silica catalysts have suggested the existence of a surface vanadium peroxo-oxo "umbrella" structure. This study definitively demonstrates with Raman and UV-vis spectroscopy that the surface vanadia peroxo-oxo umbrella-like structure is not present for both hydrated and dehydrated supported vanadia catalysts such as supported van...
The silica supported platinum nanoparticles was synthesized by using the sol-gel method. The possibility of using diamminedinitro platinum (II) as Pt precursor and effect of metal precursor concentration on the final Pt nanoparticle size was investigated. A stable silica sol was prepared via hydrolysis of tetraethyl orthosilicate (TEOS) as a metal alcoxide and condensation reaction. Subsequentl...
a series of fe3o4 supported on mesoporous fdu-12 silica systems were prepared by the hydrothermal conditions. the surface properties of the functionalized catalyst were analyzed by a series of characterization techniques like ftir, xrd, n2 adsorption–desorption and tem. xrd and adsorption–desorption analysis shows that the mesostructure of fdu silica remains intact after fe3o4 modifications, wh...
The surface force apparatus (SFA) was utilized to obtain force-distance profiles between silica-supported membranes formed by Langmuir-Blodgett deposition of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). In the absence of a membrane, a long-range electrostatic repulsion and short-range steric repulsion are measured as a result of the deprotonation of silica in water and the roughness of t...
Mesoporous silica molecular sieves are a kind of unique catalyst support due to their large pore size and high surface area. Several methods have been developed to immobilize heteropolyacids (HPAs) inside the channels of these mesoporous silicas. The mesoporous silica-supported HPA materials have been widely used as recyclable catalysts in heterogeneous systems. They have shown high catalytic a...
abstract in first part of this project, the use of a new and biguanid-like catalyst supported on silica as a recyclable catalyst provides a new route for the synthesis of a variety of arylalkylidene rhodanine derivatives through knoevenagle reaction in at present of solvent at room temperature. rhodanine derivatives and especially arylalkylidene rhodanines have proven to be attractive compound...
When used as additives, silicas strongly promoted the epoxidation of cyclooctene by (t)BuOOH in the presence of Ti-silsesquioxane (Ti-POSS), where Ti species were found to be bound to the silica surface. Based on this observation, highly-active silica-supported Ti catalysts were prepared by the thermal treatment of mixtures of Ti-POSS and silica.
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