نتایج جستجو برای: ion exchange catalyst
تعداد نتایج: 422518 فیلتر نتایج به سال:
in this thesis, a better reaction conditions for the synthesis of spirobarbiturates catalyzed by task-specific ionic liquid (2-hydroxy-n-(2-hydroxyethyl)-n,n-dimethylethanaminium formate), calcium hypochlorite ca(ocl)2 or n-bromosuccinimide (nbs) in the presence of water at room temperature by ultrasonic technique is provided. the design and synthesis of spirocycles is a challenging task becaus...
determination of uranium in natural water and complex solutions using ion exchange chromatography: a combined procedure using ion exchange chromatography and uv-vis spectrophotometry techniques has been developed to measure uranum in natural water and complex solutions. after conditicing , one hundred milli liters of sample solutions have been passed through an ion exchange column,pachked with ...
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Dowex-50W-hyodrgen ion exchange resin was used as a reusable catalyst for the synthesis of oxazoline, imidazoline and thiazoline derivatives through condensation reaction between arylnitriles and 2-aminoalcohol, ethylenediamine or 2-aminoethanthiol. This process provides several advantages such as excellent yields of the products, simple operation, convenient separation and inexpensive and recy...
Heterogeneous catalysis and their application in industrial-scale organic synthesis of fine chemicals are greatly facilitated by catalysis and further on by catalyst recovery and recycles to fits most “principles of green chemistry. In acid media, terpenoids generally undergoes various transformations. The terpenoid transformations include various liquid Bronsted and Lewis Acids, Acid clays, He...
A clean process has been developed for the synthesis of 2-adamantylphenol derivatives through adamantylation of substituted phenols with adamantanols catalyzed by commercially available and recyclable ion-exchange sulfonic acid resin in acetic acid. The sole byproduct of the adamantylation reaction, namely water, could be converted into the solvent acetic acid by addition of a slight excess of ...
Ce-ZSM-11 Zeolite: An Efficient Heterogeneous Catalyst for One-Pot Synthesis of 4H-Pyran Derivatives
ZSM-11 zeolite was synthesized by hydrothermal treatment and cerium ion was incorporated by the ion exchange method. The catalytic activity of cerium modified ZSM-11 zeolite was tested for the one-pot synthesis of 4H-pyran derivatives by cyclocondensation of aromatic aldehyde, malononitrile, and ethyl acetoacetate. The synthesized catalyst was characterized by Po...
Photocatalyst nanocomposites of ZnO/bentonite clay are synthesized by Solid-state ion exchange method. Ion exchange intercalation process of clays is used to incorporate the catalyst into the basal space of the layered structure of clays. The purpose of this study is to find a new method, which is focused on simplifying and saving time to prepare ZnO-bentonite composite with photocatalyst prope...
the fe-mcm-22 zeolite was found to be an efficient solid heterogeneous catalyst for synthesis of dihydropyrano [2,3-c] pyrazoles via one pot four component reaction of ethyl acetoacetate, hydrazine hydrate, aromatic aldehyde and malononitrile in aqueous alcohol. the catalyst was synthesized by hydrothermal method under autogenous pressure and modified by fe (iii) ion exchange. the prepared cata...
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