نتایج جستجو برای: mercury free catalyst
تعداد نتایج: 593654 فیلتر نتایج به سال:
melamine trisulfonic acid (mtsa) is utilized as a highly efficient catalyst for the solvent-free condensation reaction of 2-naphthol (2 eq.) with arylaldehydes (1 eq.) under conventional thermal as well as microwave conditions to give the d
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 ...
Poly(4-vinylpyridine)-supported copper iodide nanoparticles is reported as a new, green and recyclable catalyst for the synthesis of aryl-14H-dibenzo [a-o] xanthenes under solvent-free conditions. This catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any loss of their efficiency.
Trimethylsilylation of alcohols and phenols were carried out under solvent-free conditions with hexamethyldisilazane (HMDS) using LaCoO3 perovskite. LaCoO3 as an efficient catalyst accelerated this reaction under milder condition. The advantages of this method are evident regarding, easy separation, low cost and low catalyst loading, lack of pollution, easy work-up, and selective protection of ...
CuO-CeO2 nanocomposite is reported as a green and highly efficient recyclable catalyst for the multicomponent synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones under solvent-free conditions. The catalyst was synthesized by co-precipitation method and characterized by XRD, BET specific surface area, FESEM and EDS analysis.
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.
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.
Molybdate sulfuric acid (MSA) has been prepared and used as catalyst for the Biginelli synthesis of some quinazolinones/thiones under solvent-free conditions. The catalyst loading is low and it shows recyclability. This method has advantages such as avoidance of the organic solvents, high yield of pure products, short reaction times and operational simplicity.
Poly(4-vinylpyridine)-supported copper iodide nanoparticles is reported as a new, green and recyclable catalyst for the synthesis of aryl-14H-dibenzo [a-o] xanthenes under solvent-free conditions. This catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any loss of their efficiency.
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...
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