نتایج جستجو برای: heterogeneous catalyst
تعداد نتایج: 166602 فیلتر نتایج به سال:
cui nanoparticles as an expedient and recyclable catalyst for the synthesis of n-cyclohexyl-3-aryl-quinoxaline-2-amines in ethanol via a multi-component reaction are established. the products were separated from the catalyst simply by filtration. the catalyst could be recycled and reused for several times without noticeably decreasing the catalytic activity.
this research evaluates the efficiency of nanosized zno in the catalytic ozonation of 4-chloro-2-nitrophenol and determines the effect of ph on heterogeneous catalytic ozonation. the combined use of ozone and zno catalyst leads to conversion of 98% 4-chloro-2-nitrophenol during 5 min. in addition, it was found that in zno catalytic ozonation, the degradation efficiency of 4-chloro-2-nitrophenol...
Heterogeneous catalysis and their application in industrial-scale organic synthesis of fine chemicals are greatly facilitated by catalysis and further on by catalyst recovery and recycles to fits most “principles of green chemistry. In acid media, terpenoids generally undergoes various transformations. The terpenoid transformations include various liquid Bronsted and Lewis Acids, Acid clays, He...
The synthesis of magnetically separable quasi-homogeneous base catalyst and heterogeneous base catalyst is described. The quasi-homogeneous catalyst is achieved by supporting silane monomers functionalized with different amine groups directly on the surface of magnetite nanoparticles. The heterogeneous catalyst is prepared via a sol-gel process in which silane monomers containing different amin...
sulfonated polystyrene/montmorillonite nanocomposite (ommt/ps-so3h) was prepared and used as a novel, efficient and inexpensive heterogeneous acid catalyst in the one-pot reaction three-component mannich reaction of ketones, aromatic aldehydes and amines under solvent-free conditions. the catalyst was characterized by xrd, sem, tg, bet and ft-ir techniques. this method has advantages of high yi...
in the present work, highly efficient oxidation of sulfides catalyzed by moo2(acac)2 supported on multi-wall carbon nanotubes, mwcnts, modified with 1,2-diaminobenzene (dab) and 2-aminophenol (ap), at room temperature are reported. the effects of various parameters such as reaction time, solvent, catalyst amount, oxidant, etc, were studied. these heterogenized catalysts showed high activity in ...
in the present work, highly efficient oxidation of sulfides catalyzed by moo2(acac)2 supported on multi-wall carbon nanotubes, mwcnts, modified with 1,2-diaminobenzene (dab) and 2-aminophenol (ap), at room temperature are reported. the effects of various parameters such as reaction time, solvent, catalyst amount, oxidant, etc, were studied. these heterogenized catalysts showed high activity in ...
cobalt hydrogensulfate is an efficient catalyst for the condensation of β-naphthol, aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione at 120 °c to afford 9,9-dimethyl-12-phenyl-8,10,11,12-tetrahydro-9-h-benzo[a]xanthen-11-one derivatives in high yields. also, polycondensation reactions of phenols with phthalic anhydride were carried out in the presence of cobalt hydrogensulphate under so...
due to the high price of virgin vegetable oils and the drawbacks of the homogeneous catalytic transesterification, in this work an economically profitable alternative process was proposed for biodiesel synthesis in which transesterification of the low-cost waste cooking oil (wco) with methanol in a heterogeneous system was done. alumina impregnated with sodium hydroxide was utilized as a solid ...
freshly prepared zno nanoparticles were used as an effective heterogeneous base catalyst for the synthesis of aryloximes. the conversion of arylaldehydes and arylketones into the corresponding oximes (up to quantitative yields) was achieved by simply mixing the liquid reactants and hydroxylamine hydrochloride with zno nanoparticles under solvent-free condition. the procedure was carried out und...
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