نتایج جستجو برای: silica supported catalyst
تعداد نتایج: 268773 فیلتر نتایج به سال:
Zinc chloride silica gel-supported was found to be an efficient, inexpensive catalyst for the synthesis of 1,8-dioxodecahydroacridines via one-pot three-component condensation of aryl aldehydes, dimedone, andammonium acetate in high yields. The described novel synthetic method propose several advantages of safety, mild condition, short reaction times, high yields, simplicityand easy workup comp...
An efficient green route for the preparation of naphthoxazinones, applying a three-component one-pot condensation reaction of 2-naphthol, aromatic aldehyde and urea in the presence of nano silica supported ferric chloride under solvent-free conditions has been developed. The present procedure offers several advantages such as short reaction time, simple workup, recovery and reusability of the c...
Different sulfides were oxidized to the corresponding sulfoxides, which is useful in drug industriesand important in biological activities, with a novel magnetically separable catalyst consisting oftungstic acid supported on silica coated magnetic nanoparticles in water as a green solvent in a goodto excellent yield without any over oxidation to sulfones in a simple, selective, and eco-friendly...
Introduction We employ a combined computational-experimental approach to probe the Lewis acidity of silica-alumina, and extend this study to the effect of Lewis acidity on the activation and activity of a supported methyltrioxorhenium (MTO) metathesis catalyst. Despite the widespread use of amorphous silica-alumina as a catalyst and a catalyst support, the structures of its Lewis acid sites rem...
The partial oxidation of methanol to formaldehyde was studied over highly dispersed vanadia supported on mesoporous silica SBA-15 (VOx/SBA-15). VOx/SBA-15 catalysts were prepared by a novel grafting/ion-exchange method and characterized using UV-VISand Raman spectroscopy. The resulting surface vanadium oxide species (0 – 2.3 V/nm), grafted on the inner pores of the SBA-15 silica matrix, consist...
A new synthetic scheme towards silica-supported organotrichlorotin derivatives has been developed. It involves the synthesis of (11-triethoxysilyl)undecyltricyclohexyltin, followed by sol-gel processing and, subsequently in the formation of the resulting hybrid silica, by electrophilic substitution of the tricyclohexyltin function by the target grafted trichlorotin using tin tetrachloride. HR-M...
TiO2 nanoparticles/melamine Tri sulfonic acid (MTSA) supported on silica gel as an efficient catalytic system for simple, one pot, solvent-free and environmentally benign process for synthesis of dihydropyrimidines via Biginelli reaction at 110 °C is described. It was found that the catalyst is reusable and exhibited remarkable activity. The catalyst can be easily separated and reused several t...
TiO2 nanoparticles/melamine Tri sulfonic acid (MTSA) supported on silica gel as an efficient catalytic system for simple, one pot, solvent-free and environmentally benign process for synthesis of dihydropyrimidines via Biginelli reaction at 110 °C is described. It was found that the catalyst is reusable and exhibited remarkable activity. The catalyst can be easily separated and reuse...
Manganese oxide catalyst promoted with sodium and supported on silica exhibits fairly good activity and selectivity towards the synthesis of ethylene from methane at the optimum operating conditions. Methane and oxygen were fed into a tubular fixed bed reactor packed with catalyst under atmospheric pressure. The effects of temperature, residence time and feed composition on conversion, selectiv...
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