Lewis Acidic Ionic Liquid Research Articles

Sustainable Conjugate Addition of Indoles Catalyzed by Acidic Ionic Liquid Immobilized on Silica

A new protocol for 1,4-conjugate addition of indoles to vinyl ketones has been developed, employing Lewis acidic ionic liquid immobilized on silica, ILIS-SO2Cl, as a catalyst, which exhibited an efficient, mild and recyclable nature. The reaction condition is applicable to various vinyl ketones and indoles. The mild nature of the reaction condition showed that the acetoxy or TBDMS group in indoles was maintained intact. The catalyst was used six times resulting in 86% average yield.

Chloroferrate(III) Ionic Liquid: Efficient and Recyclable Catalyst for Solvent-free Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones

A water-tolerant Lewis acidic ionic liquid, [bmim][FeCl4], was found to be an efficient and recyclable catalyst in the synthesis of 4-aryl-dihydropyrimidinones through Biginelli condensation. This method is capable of being scaled up, if desired.

Preparation of 5-hydroymethylfurfural by dehydration of fructose in the presence of acidic ionic liquid

Abstract In this paper, preparations of 5-hydroymethylfurfural (HMF) by the dehydration of fructose in the presence of the Bronsted acidic ionic liquid, 3-allyl-1-(4-sulfobutyl)imidazolium trifluoromethanesulfonate, as well as its Lewis acid derivative, 3-allyl-1-(4-sulfurylchloride butyl)imidazolium trifluoromethanesulfonate, were investigated. It was concluded that the type of acidic ionic liquid used played a significant role in the reaction, and the Lewis acidic ionic liquid acts more effectively than its Bronsted acidic counterpart. By means of UV–visible spectroscopy, the acidities of both kinds of ionic liquids were characterized, together with an effort to correlate the relationship between acidity and activity. Moreover, it was demonstrated that when these acidic ionic liquids were immobilized on silica gel, they can be used as effective and reusable solid catalysts for the dehydration reaction of fructose to HMF, offering much better performances for the title reaction than sulfuric acid and sulfonylchloride modified silica gels in terms of activity and reusability.

Progress in Surface Finishing with Lewis Acidic Room-Temperature Chloroaluminate Ionic Liquids

In this article, we survey the progress that has been attained to date in the area of surface finishing with solvents derived from Lewis acidic room-temperature chloroaluminate ionic liquids, such as AlCl3-1-ethyl-3-methylimidazolium chloride and AlCl3-1-(1-butyl)pyridinium chloride. This field of study has received constant attention since the late 1970's. For descriptive purposes, the surface finishing technology associated with these ionic liquids is divided into four categories: Al plating, underpotential plating of binary Al alloys, overpotential plating of binary Al alloys, and overpotential plating of ternary Al alloys. We include in this report recent experimental results describing the electrodeposition of AlHf, AlW, and AlInSb alloys from the 66.7-33.3 mole percent AlCl3-1-ethyl-3-methylimidazolium chloride ionic liquid.

Liquid–liquid biphasic synthesis of long chain wax esters using the Lewis acidic ionic liquid choline chloride·2ZnCl 2

The first liquid–liquid biphasic synthesis of wax esters in a Lewis acidic ionic liquid, choline chloride·2ZnCl 2 by the esterification of long chain carboxylic acids with long chain alcohols is described. The reported reaction system has the advantages of both homogeneous and heterogeneous catalysis with high product yield and the ease of product as well as catalyst separation without the use of an organic solvent. The ionic liquid studied plays the dual role of solvent as well as catalyst and is recycled up to six times without any significant loss of activity.

Efficient synthesis of benzophenone derivatives in Lewis acid ionic liquids

Benzophenone and its derivatives were prepared via Friedel-Crafts acylation reactions using ionic liquids (ILs) of BmimCl-FeCl3, BmimCl-AICl(3) and BmimCl-ZnCl2 as dual catalyst-solvent. Among them, BmimCl-FeCl3 showed much higher catalytic activity than that observed for the other two ILs, and in conventional organic solvents. In these reaction systems, good to excellent yields (up to 97%) of acylation products were obtained in a short reaction time. This method features high yield, a simple product isolation procedure, ILs reusability and reduced waste discharge, thus rendering this catalytic system both efficient and environmentally friendly. (c) 2007 Elsevier B.V. All rights reserved.

SnCl2×2H2O — An Alternative to Lewis Acidic Ionic Liquids.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

The Synthesis of Substituted Benzo[c]chromen‐6‐ones by a Suzuki Coupling and Lactonization Sequence Using Ionic Liquids – from Laboratory Scale to Multi‐Kilogram Synthesis

AbstractA series of benzo[c]chromen‐6‐ones are prepared by a Suzuki coupling and lactonization sequence starting with 2‐methoxyphenylboronic acids and methyl 2‐bromobenzoate derivatives. The use of ionic liquids in this synthesis has been explored. It was found that the Suzuki coupling proceeds much faster when a catalytic amount of the ionic liquid [BMIM][PF6] is used. By using the Lewis acidic ionic liquids [BMIM][Al2Cl7] or [TMAH][Al2Cl7] the methyl 2‐(2‐methoxyphenyl)benzoate product obtained from the Suzuki coupling can be converted to benzo[c]chromen‐6‐ones in one step, while the conventional route involves three steps. The use of ionic liquids is demonstrated in the synthesis of a variety of benzo[c]chromen‐6‐ones. It is also shown that the application of ionic liquids is not limited to laboratory scale experiments, as a process was developed and performed on a multi‐kilogram scale. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

SnCl2·2H2O—An Alternative to Lewis Acidic Ionic Liquids

Abstract Inexpensive and commercially available SnCl2·2H2O has been shown to be an alternative to Lewis acidic ionic liquids by carrying out a variety of organic synthesis. The reaction medium is recycleable and the reaction time is comparable with the microwave reactions.

Green and moisture-stable Lewis acidic ionic liquids (choline chloride · xZnCl 2) catalyzed protection of carbonyls at room temperature under solvent-free conditions

Choline chloride · xZnCl 2 ( x = 1–3) or benzyltrimethylammonium chloride · 2ZnCl 2 have been used as efficient and recyclable catalysts for protection of carbonyls to 1,3-dioxolanes and 1,3-dioxanes at room temperature under solvent-free conditions. FT-IR investigation demonstrates the four ionic liquids have similar Lewis acid strength, which is in agreement with the activities observed in the acetalization reaction. The catalytic system choline chloride · 2ZnCl 2 can be reused up to five times without appreciable loss of activity. The simple procedures as well as easy recovery and reuse of this novel catalytic system are expected to contribute to the development of more benign acetalization procedure of carbonyl compounds.

Synthesis of diphenylmethane derivatives in Lewis acidic ionic liquids

Diphenylmethane and its derivatives were prepared via Friedel–Crafts benzylation reaction using ionic liquids of 1-butyl-3-methylimidazolium chloride-ZnCl 2 (BmimCl–ZnCl 2), 1-butyl-3-methylimidazolium chloride–FeCl 3 (BmimCl–FeCl 3) and 1-butyl-3-methylimidazolium chloride-FeCl 2 (BmimCl–FeCl 2) as both reaction media and Lewis acid catalysts. In comparison with the reaction performed in conventional organic solvent, faster reaction rate and higher selectivity to target products were achieved in such ionic liquids media. The effects of reaction temperature, reaction time, and the ratio of metal chloride to BmimCl, as well as the amount of ionic liquids on the Friedel–Crafts benzylation were also investigated. It was found that increasing reaction temperature led to high catalytic activity and selectivity, and that the excess amount of Lewis acidity of ionic liquid was detrimental to the reaction. Moreover, these ionic liquids could be conveniently recovered for recycled use; in particular, BmimCl–ZnCl 2 with moisture-stability could be reused at least eight times without loss of catalytic activity.

A Mild, Efficient and Improved Protocol for the Friedlaender Synthesis of Quinolines Using Lewis Acidic Ionic Liquid.

A Mild, Efficient and Improved Protocol for the Friedlaender Synthesis of Quinolines Using Lewis Acidic Ionic Liquid.

Preparation of ε‐Caprolactam via Beckmann Rearrangement of Cyclohexanone Oxime: A Mild and Recyclable Process.

AbstractFor Abstract see ChemInform Abstract in Full Text.

O-Acetylation of cellulose and monosaccharides using a zinc based ionic liquid

The efficient O-acetylation of monosaccharides and cellulose is demonstrated using a Lewis acidic ionic liquid based on choline chloride and zinc chloride.

A mild, efficient and improved protocol for the friedländer synthesis of quinolines using lewis acidic ionic liquid

AbstractLewis acidic ionic liquid is shown to be for the first time an excellent medium and efficient catalyst for the synthesis of quinolines at room temperature from o‐amino aromatic carbonyls and ketones containing active methylene group.

Preparation of ε-Caprolactam via Beckmann Rearrangement of Cyclohexanone Oxime: A Mild and Recyclable Process

Abstract A recyclable liquid phase process for preparation of ε-caprolactam via the Beckmann rearrangement of cyclohexanone oxime is developed by utilizing Lewis acidic ionic liquid as catalyst and a mixture of supercritical CO2 and chloroform as extractant.

Quaternary ammonium zinc- or tin-containing ionic liquids: water insensitive, recyclable catalysts for Diels–Alder reactions

Synthetically important Diels–Alder reactions occur in high yield in novel Lewis acidic ambient temperature ionic liquids composed of choline chloride–MCl2 (1:2) (M = Zn or Sn). The liquids are not moisture-sensitive and after separation of the products they can be reused with no noticeable drop in activity.

Preparation of novel, moisture-stable, Lewis-acidic ionic liquids containing quaternary ammonium salts with functional side chains.

A range of novel, moisture-stable, Lewis-acidic ionic liquids has been prepared by mixing appropriate molar ratios of MCl2 (M = Zn and/or Sn) and quaternary ammonium salts of formula [Me3NC2H4Y]Cl (Y = OH, Cl, OC(O)Me, OC(O)Ph); the influence of substituent Y and metal M on the physical properties of the melts has been investigated.

1-Ethyl-3-methylimidazolium halogenoaluminate ionic liquids as reaction media for the acylative cleavage of ethers

Ionic liquids derived from 1-ethyl-3-methylimidazolium iodide (emimI), and aluminium chloride have been shown to be suitable solvents for the acylative cleavage of a series of cyclic and acyclic ethers. Difunctionalised ω-iodobenzoate adducts have been isolated from the cleavage of cyclic ethers performed in Lewis acidic ionic liquids (i.e. AlCl 3:emimI ratio is greater than 1:1) in the presence of benzoyl chloride.

Immobilisation of chloroaluminate ionic liquids on silica materials

Two different possibilities for the preparation of immobilised ionic liquids are presented. Lewis acidic ionic liquids which have been shown to be highly active catalysts in alkylation reactions of the Friedel–Crafts type were supported on amorphous silica and MCM 41 materials. We describe the different methods used, as well as analytical data and some catalytical results achieved by these catalysts.