Search results for "ionic liquids"

Cross-Linked Polyamine from Imidazolium-Based Materials: A Simple Route to Useful Catalytic Materials

2018

Cross-linked polyamine-based materials were easily prepared by reduction of the corresponding cross-linked imidazolium-based materials with sodium borohydride in hot ethanol. Overall, the synthetic procedure is based on the polymerization of a suitable bis-vinylimidazolium salt with or without a suitable support, such as silica or silica-coated magnetic nanoparticles (γ-Fe2O3@SiO2), followed by reduction. This simple approach allows the synthesis of materials based on a network of secondary and tertiary amines. Materials were characterized by13C cross-polarization magic angle spinning NMR (13C CPMAS NMR), proton spin-lattice relaxation times in the rotating frame (T1ρH) and thermogravimet…

Hybrid ionogels as potential antioxidant agents

In the present study, the influence of CNTs on the gelling ability of some carboxylate imidazolium gelators in ionic liquid solutions has been investigated.

Bio-based 1,3-diisobutyl imidazolium hydrogen oxalate [iBu 2 IM](HC 2 O 4 ) as CO 2 shuttle

2017

International audience; This manuscript describes the using of biosourced L-valine, oxalic acid and glyoxal to produce a biobased imidazolium hydrogen oxalate [iBu(2)IM](HC2O4) which is converted to its related hydrogen carbonate salt by a simple electrolysis without using strong base. The addition of weak protic acids to the latter compound leads to a rapid and quantitative CO2 release with formation of the starting hydrogen oxalate salt or a new halide free bio-based ionic liquid [iBu(2)IM](AcO) which is able to adsorb reversibly the CO2 at room temperature. The protonation reactions, combined with electrolysis, could then be a promising alternative solution for storage and transport of C…

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.

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…

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 …