نتایج جستجو برای: green catalysts

تعداد نتایج: 172025  

Journal: :Organic & biomolecular chemistry 2013
Xi Lu Yawei Zhang Peng Yun Mingtao Zhang Tonglei Li

Knölker's iron-based catalysts have some value in "green" transformations given the relatively low toxicity of iron compared to more commonly used precious-metal catalysts. Density functional methods have been used to extensively explore the use of an iron catalyst for hydrogen-transfer processes. Several inner- (with substrate coordination) and outer-sphere mechanisms (with no substrate coordi...

2008
Cheng-Xia Miao Jin-Quan Wang Liang-Nian He

Chemical fixation of CO2 has received much attention because CO2 is the most inexpensive and renewable carbon resource from the viewpoint of green chemistry and atom economy. The kinetic and thermodynamic stability of CO2 molecule presents significant challenges in designing efficient chemical transformations based on this potential feedstock. Currently, cyclic carbonates and polycarbonates are...

Journal: :Dalton transactions 2014
Peter E Sues Karl Z Demmans Robert H Morris

The asymmetric reduction of ketones and imines by transfer of hydrogen from isopropanol as the solvent catalyzed by metal complexes is a very useful method for preparing valuable enantioenriched alcohols and amines. Described here is the development of three generations of progressively more active iron catalysts for this transformation. Key features of this process of discovery involved the re...

Journal: :Organic & biomolecular chemistry 2012
Lina Zhao Jiefeng Shen Delong Liu Yangang Liu Wanbin Zhang

Perhydroindolic acids, the by-products obtained in the industrial production of a trandolapril intermediate, were used as chiral organocatalysts in asymmetric Michael addition reactions of aldehydes to nitroolefins. These proline-like catalysts are unique for their rigid bicyclic structure with two H atoms attached to the bridgehead C atoms lying on the opposite side of the ring. They therefore...

Mahmoud Tajbakhsh Mohamad Vafakhah Navabeh Nami,

Synthesis of indole derivatives was investigated and compared to the reaction of phenylhydrazine and ketones in the presence of the heterogeneous catalysts like kaolinite, montmorillonite K10 and Fe3O4 MNPs in ethanol under reflux conditions. After comparing the HPLC chromatogram of products it was compared and found that kaolin and montmorillonite K10 are better and more efficient candidate th...

2012
Paolo Zucca Antonio Rescigno Manuela Pintus Andrea C Rinaldi Enrico Sanjust

UNLABELLED BACKGROUND Synthetic dyes represent a broad and heterogeneous class of durable pollutants, that are released in large amounts by the textile industry. The ability of two immobilized metalloporphines (structurally emulating the ligninolytic peroxidases) to bleach six chosen dyes (alizarin red S, phenosafranine, xylenol orange, methylene blue, methyl green, and methyl orange) was co...

Journal: :Crystals 2023

This manuscript reviews the current trends in recovery of Platinum Group Metals (PGMs) from end-of-life autocatalysts and aims recently funded Marie Sklodowska-Curie Project “Chemistry Metals-CHemPGM” towards greening PGMs processes reusing recovered for preparation new catalysts. Together with analysis state art spent through pyrometallurgical hydrometallurgical routes recent reducing their en...

1,4-Dihydropyridines (1,4-DHPs) are recognized as one of the most versatile pharmacophores present as central core in many pharmaceuticals. Low yield and harsh reaction conditions prompted the researchers for the development of new environmental- friendly methods for the synthesis of 1,4-DHPs. This review explored the development of various green chemistry approaches using new catalysts develop...

Hassan Ghasemnejad-Bosra Mehdi Forouzani, Navabeh Nami, Omid Khalilpour Tylami

One-pot reaction of aldehydes or ketons with aniline derivatives was performed using NaBH4 and Fe3O4 magnetic nanoparticles (MNPs). The optimum amount of Fe3O4 MNPs was 5 mol% under solvent free condition. The corresponding products were obtained in good to excellent yields. The magnetically recoverable iron oxide nanoparticles are found to be efficient for synthesis of amine derivatives. These...

Journal: :journal of the iranian chemical research 0
sedigheh vaezifar department of chemistry, university of isfahan, isfahan 81746-73441, iran fadak chemical company, isfahan science and technology town (istt), isfahan, iran hossein faghihian department of chemistry, university of isfahan, isfahan 81746-73441, iran mehdi kamali central laboratory, faculty of modern sciences & technologies, university of isfahan, isfahan 81746-73441, iran

in this research different types of al2o3 were used as supports to prepare catalysts for dehydrogenation of isobutane to isobutene. these supports were al2o3 from merck, axen and gamma al2o3 synthesized from al(oh)3. sn/pt/al2o3 catalysts were prepared by sequential impregnation, at first pt and then sn was deposited. characterization of catalysts was performed by x-ray powder diffraction (xrd)...

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