Search results for "ionic liquid"

Are deep eutectic solvents useful in chromatography? A short review.

2021

A literature update has been done concerning Deep Eutectic Solvents (DES) use in chromatography applications. The literature survey was based on the period from 2010 till 2020 and manuscripts reported in the data bases Web of Science and Scopus. The use of DES as mobile phase and mobile phase additives, stationary phases and solid phase modifiers and the use of DES as reaction solvents for chromatography use, were evaluated. Emphasis was placed on the differentiation of DES and Ionic Liquids (ILs) and the advanced green characteristics of the new solvents as compared with traditional organic solvents and ILs with a look into the drawbacks and future perspectives in the field of separation m…

Ionic Liquid Based Headspace Solid-Phase Microextraction-Gas Chromatography for the Determination of Volatile Polar Organic Compounds

2010

Solid-phase microextraction (SPME) with an ionic liquid (IL) coating was developed for headspace extraction of a group of low molecular weight alcohols (ethanol, n-propanol, butanol, and isopropyl alcohol), acetone, ethyl acetate, and acetonitrile. A first SPME fiber was simply coated with a dedicated IL whose synthesis is described. A second SPME fiber was prepared by gluing silica (Si) particles on which the synthesized IL was chemically bonded. The analytes SPME extraction was optimized for time, temperature, and NaCl salting out content. The headspace extracted analytes were determined by simple temperature desorption into the hot injection port of a gas chromatograph. The coated-IL fib…

Isobaric Vapor−Liquid and Liquid−Liquid Equilibria for Chloroform + Methanol + 1-Ethyl-3-methylimidazolium Trifluoromethanesulfonate at 100 kPa

2009

Isobaric vapor−liquid equilibria for the binary system chloroform + methanol as well as the vapor−liquid equilibria for the chloroform + methanol + [emim][triflate] ternary system have been obtained at 100 kPa using a recirculating still. The ternary ionic liquid (IL) system presents an immiscibility zone at high chloroform composition, which increases with the temperature. Liquid−liquid equilibria for this system have also been determined. The measured ternary vapor−liquid equilibrium data were correlated using the Mock’s electrolyte nonrandom two-liquid (NRTL) model which reproduces reasonably well the experimental values and predicts the total disappearance of the azeotrope when the mole…

Structure Effect of Imidazolium-Based Dicationic Ionic Liquids on Claisen Rearrangement

2014

A large group of imidazolium-based dicationic ionic liquids (DILs) has been prepared in good yields. Thermal stability of all DILs has been determined. The effects of the reaction time, cation, imidazolium C2–H acidity, and anion on the Claisen rearrangement of allyl phenyl ether have been investigated. Type of anion and the presence of the acidic C2–H bond in the imidazolium moieties have proven to be essential for this reaction. The simple procedure and the possibility of avoiding the use catalysts and volatile organic solvents make this synthetic method environmentally benign and adaptable for large-scale applications.

Solubility and solvation features of native cyclodextrins in 1-ethyl-3-methylimidazolium acetate

2022

The comprehension of the mechanism entailing efficient solvation of cyclodextrins (CD) by green solvents is of great relevance to boost environmentally sustainable usages of smart supramolecular systems. Here, 1-ethyl-3- methylimidazolium acetate, an ecofriendly ionic liquid (IL), is considered as an excellent solvent for native CDs. This IL efficiently dissolves up to 40 wt.% β- and γ-CD already at ambient temperature and X-ray scattering indicates that CDs do not tend to detrimental flocculation under these drastic concentration conditions. Simu- lation techniques reveal the intimate mechanism of CD solvation by the ionic species: while the strong hydrogen bonding acceptor acetate anion i…

When the functionalisation comes in useful: ionic liquids with a “sweet” appended moiety demonstrate drastically reduced toxicological effects

2020

The growing number of applications of ionic liquids (ILs) in industry have brought attention to the green credentials of synthesis, as well as their cytotoxicities and ecotoxicities both for their use and accidental leakage into the environment. With the abovementioned properties in mind, we designed a class of ILs with either cations bearing a gluconamide motif and aliphatic side chains or the anion incorporating a gluconic acid (derived from food waste) moiety. An IL with an imidazolium cation with an appended gluconic amide (bearing five hydroxyl groups) moiety was also synthesized for a useful comparison. Different structural features were considered, placing emphasis on the nature and …

Recent advances on ionic liquid uses in separation techniques

2018

International audience; The molten organic salts with melting point below 100°C, commonly called ionic liquids (ILs) have found numerous uses in separation sciences due to their exceptional properties as non molecular solvents, namely, a negligible vapor pressure, a high thermal stability, and unique solvating properties due to polarity and their ionic character of molten salts. Other properties, such as viscosity, boiling point, water solubility, and electrochemical window, are adjustable playing with which anion is associated with which cation. This review focuses on recent development of the uses of ILs in separation techniques actualizing our 2008 article (same authors, J. Chromatogr. A…

TASK SPECIFIC IONIC LIQUIDS: CATALIZZATORI ECOCOMPATIBILI PER LA DEPOLIMERIZZAZIONE DELLE PLASTICHE

Ionic liquid-based single-drop microextraction followed by liquid chromatography-ultraviolet spectrophotometry detection to determine typical UV filt…

2009

Abstract A user-friendly and inexpensive ionic liquid-based single-drop microextraction (IL-SDME) procedure has been developed to preconcentrate trace amounts of six typical UV filters extensively used in cosmetic products (i.e., 2-hydroxy-4-methoxybenzophenone, isoamyl 4-methoxycinnamate, 3-(4′-methylbenzylidene)camphor, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, 2-ethylhexyl 4-dimethylaminobenzoate and 2-ethylhexyl 4-methoxycinnamate) from surface water samples prior to analysis by liquid chromatography-ultraviolet spectrophotometry detection (LC-UV). A two-stage multivariate optimization approach was developed by means of a Plackett–Burman design for screening and selecting the significa…

Sensitive determination of free benzophenone-3 in human urine samples based on an ionic liquid as extractant phase in single-drop microextraction pri…

2007

Abstract Benzophenone-3 (BZ3), one of the compounds most commonly used as UV filter in cosmetic products, can be absorbed through the skin into the human body, since it can be found at trace levels in urine from users of cosmetic products that contain BZ3. Moreover, different undesirable effects have been attributed to this compound. Thus, sensitive analytical methods to monitor urinary excretion of this compound should be developed. This paper presents a selective and sensitive methodology for BZ3 determination at ultratrace levels in human urine samples. The methodology is based on a novel microextraction technique, known as single-drop microextraction (SDME). An ionic liquid (IL) has bee…