نتایج جستجو برای: recoverable catalyst
تعداد نتایج: 46271 فیلتر نتایج به سال:
A versatile and straightforward strategy to construct a xanthone skeleton via an intermolecular catalytic coupling of 2-substituted benzaldehydes and a wide range of phenols has been developed. For this purpose, a novel and magnetically recoverable catalyst consisting of copper nanoparticles on nanosized silica coated maghemite in absence of ligand is presented. The reaction proceeds smoothly w...
Low molecular water-soluble chitosan was prepared by the depolymerization of chitosan in the presence of a series of catalysts with active W(O2) sites. Both the peroxo species [W2O3(O2)4]2- and {PO4[WO(O2)2]4}3- showed high efficiency in the degradation of chitosan, indicating that the degradation mechanism did not follow the radical mechanism. That means •OH is not the active species, which ha...
N-Propylsulfamic acid supported onto magnetic Fe3O4 nanoparticles (MNPs-PSA) was investigated as an efficient and magnetically recoverable catalyst for the one-pot synthesis of substituted coumarins from the reaction of coumarin with variety aromatic aldehydes in high to excellent yield at room temperature under solvent-free conditions. The magnetic nanocatalyst can be readily recovered easily ...
In this study, a new recoverable catalyst for the epoxidation of olefins was developed using a layered polysiloxane as a support for immobilizing (salen) molybdenum(VI) complex by electrostatic interaction between the surface of the solid support and the electrically charged molybdenum complex. Characterization of the heterogeneous catalyst by Fourier transform infrared, XRD,1H NMR,...
a series of copper and cobalt substituted nanospinel ferrites have been synthesized by the hydrothermal method. these compounds were characterized by ft-ir, xrd, edx, sem and vsm techniques. all of the synthesized nanospinel ferrites were found to be highly efficient and magnetically recoverable in the solvent-free synthesis of substituted 2,6-(2-hydroxybenzyl)-phenols (trisphenols). a wide ran...
In this study, a novel method to synthesis of 1,3,5,7-tetraacetyl octahydro-1,3,5,7-tetraazocine or 1,3,5,7-tetraacetyl-1,3,5,7-tetraazacyclooctane (TAT) was used through acetolysis of 3,7-diacetyl-1,3,5,7-tetraazabicyclo-[3.3.1]nonane (DAPT) with acetic anhydride in the presence of sodium acetate as catalyst. Optimized reaction conditions were obtained by changing temperature, time and startin...
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