نتایج جستجو برای: nanomagnetic heterogeneous catalyst

تعداد نتایج: 166813  

2010
A. A. Refaat

Biodiesel production is worthy of continued study and optimization of production procedures due to its environmentally beneficial attributes and its renewable nature. Heterogeneous transesterification is considered to be a green process. The process requires neither catalyst recovery nor aqueous treatment steps and very high yields of methyl esters can be obtained, close to the theoretical valu...

2017
Ralph Skomski Jian Zhou

The atomic-scale and mesoscopic physics of magnetic nanostructures is reviewed. Emphasis is on the description of magnetic phenomena and properties by analytical models, as contrasted to numerical approaches. Nanostructuring affects the magnetic properties on different length scales, from a few interatomic distances for intrinsic properties such as magnetization and anisotropy to more than 10 n...

A heterogeneous catalyst containing manganese Schiff base complex (derived from 2,4-dihydroxybenzadehyde and 1,2-phenylenediamine) is produced by covalent anchoring in MCM-41 matrix. The synthesized catalyst was characterized by X-ray diffraction pattern (XRD), inductivity coupled plasma (ICP), Fourier transform infrared (FT-IR) spectroscopy, N2 sorbtion-desorbtion isotherm and by tr...

Journal: :iranian journal of catalysis 2015
soheil sayyahi mehdi behvandi behvandi

in this study, an efficient and green process for the synthesis of dihydropyrimidin-2(1h)-ones from aromatic benzaldehydes, ethyl acetoacetate and urea using al-mcm-41 as heterogeneous catalyst and microreactor under solvent-free conditions has been developed. the advantages of this method are easy work-up procedure, regeneration of the catalyst, clean and neutral reaction conditions.

3,3,6,6-Tetramethyl-9-phenyl-3,4,6,7,9,10-hexahydroacridine-1,8-(2H,5H)-dione derivatives are synthesized by nano titanium dioxide as an efficient and reusable heterogeneous nano catalyst in a one pot multi component reaction. Easy preparation and separation of catalyst, simply workup procedure, clean reaction and reusability of the catalyst up to 7 times without appreciable loss of its catalyt...

2008
Jan Hájek Mieke Dams Christophe Detrembleur Robert Jérôme Pierre A. Jacobs Dirk E. De Vos

A novel heterogeneous Pd/polymer catalyst containing co-catalytic functional groups catalyses the direct alkenylation of anisole with ethyl trans-cinnamate under oxygen. The properties of the polymeric catalyst were compared to other immobilised catalysts. The activity of the polymeric catalyst typically increased with temperature and oxygen pressure exhibiting the optimal activity up to 100 TO...

Journal: :Chemical science 2017
Hong-Gang Cheng Javier Miguélez Hiroyuki Miyamura Woo-Jin Yoo Shū Kobayashi

A new class of chiral bifunctional heterogeneous materials composed of Au/Pd nanoparticles and chiral phosphoric acids as active orthogonal catalysts was prepared by utilizing a facile pseudo-suspension co-polymerization method. It was found that this heterogeneous catalyst was capable of facilitating the sequential aerobic oxidation-asymmetric intramolecular aza-Friedel-Crafts reaction between...

2017
Hong-Gang Cheng Javier Miguélez Hiroyuki Miyamura Woo-Jin Yoo Shū Kobayashi

A new class of chiral bifunctional heterogeneous materials composed of Au/Pd nanoparticles and chiral phosphoric acids as active orthogonal catalysts was prepared by utilizing a facile pseudo-suspension copolymerization method. It was found that this heterogeneous catalyst was capable of facilitating the sequential aerobic oxidation-asymmetric intramolecular aza-Friedel–Crafts reaction between ...

Mehdi Behvandi Behvandi Soheil Sayyahi,

In this study, an efficient and green process for the synthesis of dihydropyrimidin-2(1H)-ones from aromatic benzaldehydes, ethyl acetoacetate and urea using Al-MCM-41 as heterogeneous catalyst and microreactor under solvent-free conditions has been developed. The advantages of this method are easy work-up procedure, regeneration of the catalyst, clean and neutral reaction conditions.

A highly efficient and general method for the synthesis of aryloylamido coumarinsderivatives by a three-component condensation of 4-hydroxycoumarin or 4-hydroxy-6-methylpyran-1-one, aryl glyoxals and benzamide in the presence of nano silica supported tin(II) chloride as a heterogeneous catalyst is established. In this method, SnCl2/nano SiO2 wasused as green and reusable catalyst. Excellent yie...

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