نتایج جستجو برای: recoverable catalyst
تعداد نتایج: 46271 فیلتر نتایج به سال:
ABSTRACT Polyvinylpolypyrrolidone supported chlorosulfonic acid ([PVPP-SO3H]+Cl-) was synthesized and evaluated as a recoverable catalyst for the one-pot synthesis of hexahydroquinolines by reaction of arylaldehydes, dimedone (5,5-dimethylcyclohexane-1,3-dione) or 1,3-cyclohexanedione, ethylacetoacetate and ammonium acetate in high to excellent yield in ethanol at 70 °C. The [PVPP-SO3H]+Cl- cat...
A Pd-based heterogeneous catalyst (Pd(II)-MCM-41) derived from post-synthesis modification of mesoporous silica, MCM-41, has been successfully employed in catalytic Stille and Sonogashira cross-coupling reactions. The catalyst affords good yields in all cross-coupling reactions. Notably, the catalyst is capable of activating less reactive chlorobenzene with moderate yield in both the coupling r...
2-Methylpyridinum p-toluenesulfonate ([2-MPy][p-TSA]) as a novel room temperature ionic liquidwas synthesized and evaluated as a recoverable catalyst for the one-pot synthesis ofhexahydroquinoline-3-carboxamide derivatives by four-component reaction of arylaldehydes,dimedone, acetoacetanilide and ammonium acetate in high to excellent yield in ethanol at 50 oC.The [2-MPy]...
In this paper, Fe3O4-chitosan nanoparticles were prepared by the immobilization of chitosan on the surface of Fe3O4 nanoparticles. Then, the 5-substituted hydantoins were synthesized from the condensation of aldehyde derivatives, ammonium carbonate and zinc cyanide as a well-known cyanating agent by the magnetic Fe3O4-chitosan nanoparticles under neat conditions. Fe3O4-Chitosan nanocatalyst as ...
An efficient and green method has been developed for the synthesis of new substituted Hantzsch thiazole derivatives in 79%-90% yield, via the one-pot multi-component procedure, by the reaction of 3-(bromoacetyl)-4-hydroxy-6-methyl-2H-pyran-2-one, thiourea and substituted benzaldehydes in the presence of silica supported tungstosilisic acid, as a reusable catalyst, under conventional heating or ...
a new type of magnetically-recoverable catalyst was synthesized by the immobilization of h3pw12o40 on the surface of silica-encapsulated -fe2o3 nanoparticles. a series of novel 1,3,5-triaryl pyrazoline derivatives has been synthesized by the reaction of chalcone and phenylhydrazine in the presence of the -fe2o3@sio2-pw12nanoparticles, in high yields. the structures of compounds obtained were...
palladium is the best metal catalyst for suzuki cross coupling reaction for synthesize of unsymmetrical biaryl compounds. but its high cost limits its application in wide scale. using of nanoscale particles as active catalytic cites is a good approach for reducing needed noble metal. by loading precious nanoparticles on magnetic nanocores as a support, recycling and reusing of catalyst will be ...
ABSTRACT Polyvinylpolypyrrolidone supported chlorosulfonic acid ([PVPP-SO3H]+Cl-) was synthesized and evaluated as a recoverable catalyst for the one-pot synthesis of hexahydroquinolines by reaction of arylaldehydes, dimedone (5,5-dimethylcyclohexane-1,3-dione) or 1,3-cyclohexanedione, ethylacetoacetate and ammonium acetate in high to excellent yield in ethanol at 70 °C. The [PVPP-SO3H]+Cl- cat...
The photocatalytic activity of Mn doped TiO2 for the ozonation of tetradifon pesticide in aqueous solution was studied. Various loadings of catalysts Mn/TiO2 (1%, 2.5% and 5%) was prepared and characterized by standard analytical techniques. Photocatalyzed ozonation with 2.5% Mn/TiO2 yielded 100% degradation and mineralization of tetradifon in 2.0 h under basic pH conditions. The extent of degr...
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