نتایج جستجو برای: solid phase and recyclable basic catalyst
تعداد نتایج: 16989339 فیلتر نتایج به سال:
A large number of chemical, bio-chemical and pollution-control processes use heterogeneous fixed-bed reactors. The use of finite hollow cylindrical catalyst pellets can enhance conversion levels in such reactors. The absence of the pellet core can significantly lower the diffusional resistance associated with the solid phase. This leads to a better utilization of the catalytic material, which i...
An efficient and environmental-friendly synthetic route to 1,8-dioxodecahydroacridines derivatives have been developed via multi-component one-pot Hantzsch reaction of various aldehydes and ammonium acetate with 2 equivalents dimedone in the presence of Phosphorus pentoxide supported on aluminaas catalyst under solvent-free conditions. The present approach offersseveral advantages such as short...
A new method for the synthesis of formamides has been developed by the N-formylation of amines with formic acid in the presence of nano cerium oxide as an efficient and recyclable catalyst under ultrasound irradiation. The reaction system is remarkably simple and environmentally benign.
the purpose of this study was to examine the english language needs of medical students at tehran university of medical sciences . analysis of the needs took place for three groups: 320 undergraduate students, 30 postgraduate students and 20 university instructors. a triangulation approach to collect data was used in which a combination of the quantitative (using the questionnaires) and qualita...
Phosphotungstic acid (H(3)PW(12)O(40)) was used as an efficient and recyclable catalyst for the synthesis of polysubstituted quinolines through the Friedländer condensation of 2-aminoarylketone with carbonyl compounds, which was achieved by conventional heating under solvent-free conditions.
A series of tunable axial chiral bisphosphine ligands have been synthesized from (S)-MeO-Biphep. The Ir complex of the MeO-PEG-supported ligand (S)-4k has been successfully applied in asymmetric hydrogenation of quinolines with up to 92% ee. The catalyst system is air-stable and recyclable.
An efficient and environmental-friendly synthetic route to 1,8-dioxodecahydroacridines derivatives have been developed via multi-component one-pot Hantzsch reaction of various aldehydes and ammonium acetate with 2 equivalents dimedone in the presence of Phosphorus pentoxide supported on aluminaas catalyst under solvent-free conditions. The present approach offersseveral advantages such as s...
An efficient and environmental-friendly synthetic route to 1,8-dioxodecahydroacridines derivatives have been developed via multi-component one-pot Hantzsch reaction of various aldehydes and ammonium acetate with 2 equivalents dimedone in the presence of Phosphorus pentoxide supported on aluminaas catalyst under solvent-free conditions. The present approach offersseveral advantages such as s...
In this research, we have developed cheap recyclable and task-specific acidic ionic liquids (AILs) 1-hydrogen-3-methylimidazolium hydrogen sulfate [Hmim]HSO4, 1-hydrogen-3-methylimidazolium chloride [Hmim]Cl, 2-pyrrolidonium hydrogensulfate [Hnhp]HSO4 and applied them in acid catalyzed synthesis of quinoxaline derivatives from 1,2-phenylendiamines and 1,2-dicarbonyl compounds. The products coul...
Porous and robust 12-connected metal-organic frameworks (MOFs) were constructed by linking tetranuclear lanthanide (Ln) carbonate clusters with organoboron-derived tricarboxylate bridging ligands. The high-connectivity Ln-MOFs feature remarkable thermal and hydrolytic stability and a large number of isolated Lewis acid B(III) and Ln(III) sites on the pore surfaces. The Nd-MOF assisted with sodi...
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