Preparation of Silica Supported Ionic Liquids for Highly Selective Hydroxylation of Aromatics with Hydrogen Peroxide under Solvent-free Conditions

Abstract

A series of silica supported functionalized ionic liquid catalysts have been prepared and tested in the hydroxylation of aromatics to phenols with H<sub>2</sub>O<sub>2</sub> under solvent-free conditions. The properties of the heterogeneous catalytic system were studied by tuning various reaction parameters including selection of catalyst, amount of the catalyst, influences of reaction time and temperature. Among the catalysts, CuCl<sub>3</sub>-IL-SiO<sub>2</sub> exhibited the highest efficiency in the hydroxylation of aromatics to phenols under the optimized condition along with good recycle performance.

CO2 capture using silica-immobilized dicationic ionic liquids with magnetic and non-magnetic properties

“…The SBA@DIL_2Cl anion exchange reaction ( Fig. 5 ) was performed according to a procedure adapted from the literature [ 48 , 49 ]. The mixture of LiNTf 2 salt (in 50 mL of distilled water) and immobilized DIL_2Cl (2:1 ratio) was stirred at room temperature for 78 h. Subsequently, the mixture was filtered, repeatedly washed with deionized water, and extracted with soxhlet using first deionized water and dichloromethane, which removed the unreacted products and produced SBA@DIL_2NTf 2 .…”

Synthesis, Characterization and Optimization of Oleyl Oleate Wax Ester Using Ionic Liquid Catalysts

“…The three steps are all typical acid-catalyzed reactions. Therefore, the outcome of the esterification reaction depends very much on the acidity of the catalyst [17][18]. However, acidity determinations based on room temperature Brønsted acidic ionic liquids are a relatively new subject.…”

Chloroaluminate Ionic Liquid Immobilized on Magnetic Nanoparticles as a Heterogeneous Lewis Acidic Catalyst for the Friedel–Crafts Sulfonylation of Aromatic Compounds

“…Contrarily, heterogeneous catalysts could be recovered and recycled conveniently and efficiently, although their dispersion in reaction media have not been carried out well. To overcome these problems in the dispersion, recovery, and recycling of catalysts, ionic liquids have been immobilized onto solid materials such as organic polymers [ 42 , 43 , 44 ], inorganic supports (e.g., silica, alumina) [ 45 , 46 , 47 , 48 ], and magnetic nanoparticles (MNPs) [ 49 , 50 , 51 , 52 , 53 , 54 , 55 ]. The improved catalysts have possessed the combined properties of homogeneous and heterogeneous catalysts, consisting of a larger surface area and catalyst-loading capacity, better dispersity in reaction media, and simple separation.…”