نتایج جستجو برای: catalyst free
تعداد نتایج: 553796 فیلتر نتایج به سال:
in this research, (carboxy-3-oxopropylamino)-3-propylsilylcellulose (copapsc) as an organocatalyst, has been synthesized by grafting of succinic anhydride on the nh2-modified cellulose (cellulose functionalized with 3- aminopropyltriethoxysilane). the –co2h group-functionalized cellulose (copapsc) is used as a catalyst for the synthesis of coumarin derivatives from the reaction of phenolic subs...
the acetylation of various alcohols and phenols was performed successfully using acetic anhydride in the presence of citric acid coated magnetite nanoparticles as catalyst under solvent-free condition and at 45 °c. the catalyst showed high thermal stability and was recovered and reused at least 5 times without any considerable loss of activity. the present process is environmentally benign and ...
d-tartaric acid is successfully used as a green and efficient catalyst for the synthesis of 3,4-dihydropyrimidin-2(1h)-ones under solvent-free conditions. the developed method has many advantages, including devoid of harmful catalyst and solvents, high yield and easily work-up.
The palladium nanoparticles were immobilized on DNA-modified multi walled carbon nanotubes as stable and powerful heterogeneous catalyst. The catalyst was characterized by FT-IR spectroscopy, UV-Vis spectroscopy, field emission scanning electron microscopy, X-ray diffraction, transmission electron microscopy, inductively coupled plasma and elemental analysis. DNA as a well-defined structure and...
the present study aimed to use a method for the synthesis of some 3, 4-dihydropyrimidin-2-(1h) - ones/thiones. the study tried to answer the question whether this reaction can be performed without solvent and with new catalyst or not. to find answer to the question, we described a novel protocol for the efficient synthesis of 3, 4-dihydropyrimidin-2-(1h)-one derivatives using aromatic aldehyde,...
in this paper, 4,4ʹ-bipyridinium dichloride supported sba-15 (sba@bipy2+ 2cl-) was used for the synthesis of dihydropyrimidinones. the synthesized catalyst was characterized by ft-ir spectroscopy, scanning electron microscopy (sem), transmission electron microscopy (tem) and thermogravimetric analysis (tga). this nanocomposite was shown to be an efficient heterogeneous catalyst for the synthes...
sulfonated polystyrene/montmorillonite nanocomposite (ommt/ps-so3h) was prepared and used as a novel, efficient and inexpensive heterogeneous acid catalyst in the one-pot reaction three-component mannich reaction of ketones, aromatic aldehydes and amines under solvent-free conditions. the catalyst was characterized by xrd, sem, tg, bet and ft-ir techniques. this method has advantages of high yi...
A convenient synthetic method for the synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetra substituted imidazole derivatives, has been developed via one-pot condensation reaction in solvent-free condition when aldehyde, ammonium acetate/amine, and 1,2-diketone are reacted using 0.8 mol% of NP-LaMnO3 at 80 °C under solvent free conditions. Catalyst could be recovered and reused in five reaction c...
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