Ionic Liquids Immobilized on Magnetic Nanoparticles

Ionic liquids (ILs) immobilized on supports are among the most important derivatives of ILs. The immobilization process of ILs can transfer their desired properties to substrates. The combination of the advantages of ILs with those of support materials will derive new performances while retaining the properties of both moieties. As green media in organic catalytic reactions, based on utilizing the ability of ILs to stabilize the catalysts, they have many advantages over free ILs, including avoiding the leaching of ILs, reducing their amount, and improving the recoverability and reusability of both themselves and catalysts. This has critical significance from both environmental and economical points of view. Recently, ionic liquids immobilized on magnetic nanoparticles (MNPs) have drawn increasing attention in catalytic reactions and separation technologies and achieved substantial progress. The combination of MNPs and ILs gives magnetic‐supported ionic liquids, which exhibit the unique properties of ILs as well as facile separation by an external magnetic field. The excellent efficiency of this kind of immobilized ionic liquids offers a great advantage compared with other sorts of magnetic supports. In this chapter, the green catalytic processes and recent advances in organic synthesis catalyzed by ionic liquids immobilized on magnetic nanoparticles are highlighted

Polyvinylpyrrolidone-bromine complex: An efficient polymeric reagent for selective preparation of benzyl bromides in the presence of hexamethyldisilane

Benzylic bromides were conveniently obtained in high yields via the reaction of the corresponding alcohols with crosslinked polyvinylpyrrolidone-bromine complex (PVPP-Br2)/hexamethyldisilane in chloroform at reflux condition. Selective conversion of benzyl alcohol to benzyl bromide in the presence of primary aliphatic alcohols, e.g. 2-phenylethanol was also achieved. KEY WORDS: Polyvinylpyrrolidone-bromine, Benzyl bromide, Hexamethyldisilane, Selective bromination Bull. Chem. Soc. Ethiop. 2012, 26(2), 305-309.DOI: http://dx.doi.org/10.4314/bcse.v26i2.1

Nano magnetite (Fe3O4), an efficient and robust catalyst for the one-pot synthesis of 1-(aryl(piperidin-1-yl)methyl)naphthalene-2-ol and 1-(α-amido alkyl)-2-naphthol under ultrasound irradiation

The direct three component reaction via condensation of aldehydes, 2-naphthol and piperidine or acetamide to generate 1-(aryl(piperidin-1-yl)methyl)naphthalene-2-ol and N-((2-hydroxy naphthalene-1-yl)(aryl)methyl)acetamide derivatives has been carried out over Fe3O4 magnetic nanoparticle with high efficiency under ultrasound irradiation. These reactions were studied under different conditions. In terms of reaction time and yield, it was found that optimum results were obtained for the synthesis of 1-(aryl(piperidin-1-yl)methyl)naphthalene-2-ol under solvent free condition and for preparation of N-((2-hydroxynaphthalene-1-yl)(aryl)methyl)acetamide in acetic acid under ultrasound irradiation at 80 °C. Clean methodologies, easy workup procedure, and high yields are some advantages of this work

Tungstosilicic Acid: An Efficient and Ecofriendly Catalyst for the Conversion of Alcohols to Alkyl Iodides

Treatment of a range of benzylic, allylic, and secondary aliphatic alcohols with potassium iodides in the presence of H4SiW12O40 affords the corresponding alkyl iodides in good to excellent yield with straightforward purification at room temperature in CH3CN

Polyvinylpolypyrrolidone-Supported Boron Trifluoride; Highly Efficient Catalyst for the Synthesis of N-tert-Butyl Amides

Abstract: Highly efficient method for the preparation of N-tert-butyl amides by reaction of nitriles with tert-butyl acetate is described using polyvinylpolypyrrolidone-supported boron trifluoride (PVPP-BF 3 ) at 70 °C in good to excellent yields. Selective amidation of benzonitrile in the presence of acetonitrile was also achieved. polyvinylpolypyrrolidone-boron trifluoride complex shows non-corrosive and stable solid catalyst elevated Lewis acid property

Polyvinylpolypyrrolidone-Supported Boron Trifluoride; Highly Efficient Catalyst for the Synthesis of N-tert-Butyl Amides

Highly efficient method for the preparation of N-tert-butyl amides by reaction of nitriles with tert-butyl acetate is described using polyvinylpolypyrrolidone-supported boron trifluoride (PVPP-BF3) at 70°C in good to excellent yields. Selective amidation of benzonitrile in the presence of acetonitrile was also achieved. polyvinylpolypyrrolidone-boron trifluoride complex shows non-corrosive and stable solid catalyst elevated Lewis acid property

Tin oxide nanoparticles (SnO2-NPs): An efficient catalyst for the one-pot synthesis of highly substituted imidazole derivatives

AbstractIn this work, direct three component condensation of 9,10-phenanthraquinone or acenaphthenequinone with aryl aldehyde and ammonium acetate to generate highly substituted imidazole derivatives was performed over tin oxide nanoparticles. The resulting reactions were conducted at high efficiency in ethanol under reflux conditions