نتایج جستجو برای: heterogenous solid acid
تعداد نتایج: 926676 فیلتر نتایج به سال:
The methodology involves preparing polyvinyl sulfuric acid as a solid acid by simple mixing ofpolyvinyl alcohol with chlorosulfonic acid in CH2Cl2 at room temperature. The catalytic ability ofthe solid acid was investigated for the facile conversion of benzylic alcohols to the unsymmetricalethers with aliphatic alcohols in the presence of the solid acid. Results show that the solid acid isan ap...
Sulfuric acid ([3-(3-silicapropyl)sulfanyl]propyl]ester (SASPSPE) is employed as a recyclable catalyst for the silylation of hydroxyl groups. A good range of primary, secondary alcohols and phenolic hydroxyl groups were effectively converted into their corresponding trimethylsilyl ethers with hexamethyldisilazane in the presence of catalytic amounts of SASPSPE at room temperature with short rea...
Effective conversion of lignocellulosic material as renewable energy source has significant reflection on economic and environmental impact. Diluted acid hydrolysis at optimal condition was used to liberate fermentable sugar. The sorghum stalks, the alkali pretreatment of biomass and hydrolysis in diluted hydrochloric acid were investigated. The hydrolysis reaction was carried out in a 5L react...
quinolines, an important class of potentially bioactive compounds, have been synthesized by treatment of o-aminoarylketones and carbonyl compounds utilizing niobium (v) chloride / polyethylenglycole(nbcl5.peg) and niobium(v)chloride (nbcl5) as available and inexpensive catalysts. the quinoline derivatives were prepared in glycerol, an excellent solvent in terms of environmental impact, with hig...
In this paper the tunable M-channel filters based on Thue-Morse heterostructures consisting of single -negative materials has been studied. The results showed that the number of resonance modes inside the zero- gap increases as the number of heterogenous interface, M, increases. The number of resonance modes inside the zero- gap is equal to that of heterogenous interface M, and it can be used a...
Palm oil solid wastes consist of cellulose, hemicellulose and lignin. In this study, a single stage of acid hydrolysis process of palm oil empty fruit bunch (EFB) for production of fermentable sugar was carried out under moderate temperature (45°C) and ambient pressure. The effect of four different process variables such as solid size, HCl concentration, solid percentage and temperature were in...
an efficient and simple procedure for the synthesis of 1,8-dioxo-octahydroxanthenes from the aromatic aldehydes and 5,5-dimethylcyclohexane-1,3-dione (dimedone) in the presence of boric acid [bo3h3 or b(oh)3] as an inexpensive and reusable catalyst is described. the salient features of this methodology are: the elimination of corrosive liquid acids, high yields, simple methodology, short reacti...
Sarcomas are rare and heterogenous tumours that constitute fewer than 1% of adult solid cancers.1 Owing to their aggressive behaviour, relative rarity occurrence at multiple anatomical sites, sarcomas can be challenging treat.2
silica-bonded n-propyldiethylenetriamine sulfamic acid (sbpdsa) was found as an efficient solid acid for the synthesis of coumarins. coumarin derivatives were obtained via the pechmann condensation reaction of phenols and β-keto-esters at 80 oc under solvent-free conditions. also, biscoumarins were obtained via the condensation of aldehydes and 4-hydroxycoumarin in water at reflux conditions. t...
Sulfuric acid ([3-(3-silicapropyl)sulfanyl]propyl]ester (SASPSPE) is employed as a recyclable catalyst for the silylation of hydroxyl groups. A good range of primary, secondary alcohols and phenolic hydroxyl groups were effectively converted into their corresponding trimethylsilyl ethers with hexamethyldisilazane in the presence of catalytic amounts of SASPSPE at room temperature with short rea...
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