نتایج جستجو برای: catalyst reusability
تعداد نتایج: 48764 فیلتر نتایج به سال:
Background and purpose: Photocatalysis process with TiO2 is a well-known method for removal of pollutants from water. However, the small particle size of TiO2, and therefore difficulty in its separation after treatment impede its commercialization. The aim of this study was to synthetize the Fe3O4@SiO2@TiO2 magnetic nanoparticles (NPs) and evaluation of its efficiency in removal of metronidazol...
An efficient, simple and convenient route is described for the synthesis of biscoumarin (3,3'-(arylmethylene) bis (4-hydroxy-2H-chromen-2-one)) by using of recyclable catalyst TiO2@KSF. In this Method, we synthesis biscoumarin derivatives via 3multi-component reactions (3MCRs) of two equivalent 4-hydroxycoumarin with one equivalent of aromatic aldehydes using 20 mg nano TiO2@KSF as homogeneous ...
In this work, the SBA-15-supported dithizone-copper(I) [SBA-15-dtz–Cu(I)] complex as a new heterogeneous catalyst is prepared for the first time. The catalyst prepared is characterized by the FT-IR spectroscopy, SEM, and ICP techniques. This reusable heterogeneous catalyst can be used in the click reactions for the green and facile synthesis of 1,4-disubstituted 1,2,3-triazolesvia a on...
Sulfonic acid functionalized nanoporous silica (SBA-Pr-SO3H) with a pore size of 6 nm catalyzed three component coupling of aromatic aldehydes, urea and ethyl acetoacetate to afford the corresponding dihydropyrimidinones under solvent free condition. This new protocol for Biginelli reaction has important advantages such as green synthesis, short reaction time, easy isolation and high yields of ...
Manganese metal-organic framework (Mn-MOF) containing Mn2+ ions, benzenetricarboxylic acid (BTC) and N,N-dimethylformamid (DMF) was prepared and used as catalyst for oxidation of alkenes such as 1,1-diphenylethylene, trans-stilbene, cyclohexene, norbornene, styrene and cyclooctene to epoxides with 33-92% conversion and 75-100% selectivity and oxidation of alkanes such as fluorene, adamantane, e...
a two-dimensional nanolayered polyoxomolybdate, [4,4´-h2bipy] [mo7o22].h2o (1), where 4,4´-bipy = 4,4´-bipyridine, was prepared and characterized by ft-ir and atomic absorption spectroscopies, transmission electron microscopy (tem), x-ray single crystal and powder diffraction (xrd), and thermogravimetric analysis. the catalytic performance of 1 was assessed in the epoxidation of some olefins em...
5-acetyl-6-methyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones were synthesized in good to excellent by one-pot three-component Biginelli condensation in the presence of ammonium salt [Et3NH][HSO4] as an inexpensive and green catalyst under solvent-free conditions. High yields, short reaction time, easy work-up, a green environment which requires no toxic o...
A rapid and efficient method for the synthesis of bis-thiazolidinones has been achieved by pseudo five-component reaction of aldehydes, ethylenediamine and thioglycolic acid in the presence of nano-NiZr4(PO4)6 as catalyst under microwave irradiation. Nano-NiZr4(PO4)6 has been characterized by powder X-ray diffraction, scanning electronic microscopy (SEM), energy dispersive spectroscopy (EDS), v...
An efficient four-component synthesis of benzopyranopyridines is described by one-pot condensation of salicylaldehydes, thiols and 2 equiv of malononitrile with nano-PbWO4 as a robust and reusableheterogeneous catalyst under ultrasonic irradiation. Lead tungstate (PbWO4) nanostructures have been synthesized via a sonochemical method based on the reaction between l...
An efficient and green protocol for the synthesis of 2-arylsubstituted benzimidazoles via a condensation reaction of aromatic aldehydes and 1,2-phenylenediamine using nano-Fe3O4@SiO2-SO3H as a solid acid catalyst in ethanol under reflux conditions has been described. The reactions are completed in short times, and the corresponding benzimidaz...
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