Search results for "ionic liquid"

Alkylation of ambident indole anion in ionic liquids

2007

AbstractAlkylation of indole salts in different ionic liquids is reported. Ionic liquids increase the alkylation reaction rate of ambident indole anion and reduce the effects of counter ions and/or additives, the alkylation reaction rates being independent of the presence of small amounts of protic solvents or water.

A polyhedral oligomeric silsesquioxane-based catalyst for the efficient synthesis of cyclic carbonates

2015

Polyhedral oligomeric silsesquioxane functionalized with imidazolium chloride peripheries (POSS-Imi) was successfully synthesized through a novel synthesis protocol. The solid was extensively characterized via1H NMR, 13C NMR and IR spectroscopy as well as combustion chemical analysis, mass spectrometry and transmission electron microscopy. Moreover, an in-depth investigation through 29Si NMR was performed. POSS-Imi was used for the first time as a catalyst for the conversion of CO2 and epoxides into cyclic carbonates with excellent results in terms of both yield and selectivity. The catalyst displayed improved catalytic performance with respect to unsupported 1-butyl-3-methylimidazolium chl…

Estimation of Solute-Stationary Phase and Solute-Mobile Phase Interactions in the Presence of Ionic Liquids

2019

The presence of free silanols on alkyl-bonded reversed-phase stationary phases is responsible for broad and asymmetrical peaks when basic drugs are chromatographed with conventional octadecylsilane (C18) columns due to ionic interactions. In the last few years, ionic liquids (ILs) have attracted attention to reduce this undesirable silanol activity. ILs should be considered as dual modifiers (with a cationic and anionic character), which means that both cations and anions are able to adsorb on the stationary phase, creating a positively or negatively charged layer, depending on the relative adsorption. The accessibility of basic compounds to the silanols is prevented by both the IL cation a…

Self strengthening, Load Bearing Ionic Liquid Gels for Environmental Remediation

Di- and Tricationic Organic Salts: an Overview of Their Properties and Applications

2014

During recent years growing interest has been devoted to the synthesis and applications of polycationic organic salts. Among them, di- and tricationic organic salts can be considered the natural evolution of monocationic ones. These last have given rise to the large class of ionic liquids. In the cases of di- and tricationic organic salts, the potential to change their structural features simply by varying the properties either of the charged heads or of the spacers separating them provides the opportunity to obtain materials suitable for different applications. This review article highlights recent progress in the study of the properties of di- and tricationic organic salts, as well as in …

Ionic liquid crystals based on 3-perfluoalkyl-1,2,4-triazol-4-ium salts

2016

Liquid-crystalline ionic liquids (LC-ILs) are a class of organic materials that of great current interest: they are defined as organic salts that possess the properties of two interesting kinds of material – ionic liquids (ILs) and liquid crystals (LCs). LC-ILs combine many interesting features of ILs (e.g. low volatility and the ability to dissolve solutes with a range of polarities) as well as many attractive properties of LCs (e.g. their intrinsic order and anisotropy). This provides unique opportunities that can be exploited in many different fields, for example their use as solvents for extraction processes as well as electrolytes for batteries, fuel cells, and dye-sensitised solar cel…

Anion and ionic liquid effects on ionogel phases formation

Geminal organic salts have been recently introduced as the third generation of ionic liquids.1 Like their monocationic precursors they generally show high thermal stability and low corrosiveness, as well as high polarity and structural order degree.2 All these features make them good candidates to be used in the formation of conductive gel phases, that afterwards may find application as organized reaction media or in the preparation of dye sensitized solar cells.3 In this context, we have recently synthesized some task specific geminal organic salts and investigated their behaviour as gelators. The obtained salts were able to gel ionic liquid solutions. In order to have information about th…

STABILITY OF ELECTROGENERATED N-HETEROCYCLIC CARBENES FROM IONIC LIQUIDS. THE BOUNDARY CONDITIONS

Polyhedral Oligomeric Silsesquioxane Based Catalyst for the Efficient Synthesis of Cyclic Carbonates

2015

In this work, the synthesis of a novel imidazolium-based polyhedral oligomeric silsesquioxane (POSS-mim-Cl) material is presented. The new nanometer-size organosilica based compound was employed for chemical fixation of CO2 into epoxide under homogeneous conditions. The target reaction was represented by the obtention of cyclic carbonates starting from epoxides and CO2. Particularly, styrene oxide was chosen as reference substrate. In addition, different parameters (solvent, temperature, pressure of CO2, and mass of the catalyst) were modified to find the best condition for CO2 conversion. The catalyst POSS-mim-Cl displayed good catalytic performances, the best results being obtained at 40 …

IONIC LIQUIDS MODIFIED CATALYSTS: SYNTHESIS, IMMOBILIZATION AND USES.

Synthesis, catalytic activity and recovery of Ionic liquid modified and un-modified catalysts have mainly been focused in this thesis. Particularly, our attention has been given to 2,2,6,6-Tetramethyl-piperidine-N-oxyl (TEMPO) catalyst for its unique redox behavior in alcohol oxidation to carbonyl compounds. In order to tag appropriate number of IL moieties, [60]Fullerene as well as benzylic linker units were employed as a molecular support. However, covalently supported catalysts were recovered by a short silica pad while, ionic liquid-tagged TEMPO catalysts were recovered by a non-covalent “Release and Catch” approach using silica grafted polymeric multilayered covalently supported ionic …