Trialkylsulfonium and tetraalkylammonium cations-based ionic liquid electrolytes for quasi-solid-state dye-sensitized solar cells

Bis(trifluoromethylsulfonyl)imide Ionic Liquids Applied for Fine-Tuning the Cure Characteristics and Performance of Natural Rubber Composites

The goal of this work was to apply ionic liquids (ILs) with bis(trifluoromethylsulfonyl)imide anion (TFSI) for fine-tuning the cure characteristics and physico-chemical properties of elastomer composites based on a biodegradable natural rubber (NR) matrix. ILs with TFSI anion and different cations, such as alkylpyrrolidinium, alkylammonium, and alkylsulfonium cations, were applied to increase the efficiency of sulfur vulcanization and to improve the performance of NR composites. Thus, the influence of ILs on the vulcanization of NR compounds, as well as crosslink density and physical properties of NR vulcanizates, including tensile properties, thermal stability, and resistance to thermo-oxidative aging was explored. The activity of ILs seems to be strongly dependent on their cation. Pyrrolidinium and ammonium ILs effectively supported the vulcanization, reducing the optimal vulcanization time and temperature of NR compounds and increasing the crosslink density of the vulcanizates. Consequently, vulcanizates with these ILs exhibited higher tensile strength than the benchmark without IL. On the other hand, sulfonium ILs reduced the torque increment owing to the lower crosslinking degree of elastomer but significantly improved the resistance of NR composites to thermo-oxidation. Thus, TFSI ILs can be used to align the curing behavior and performance of NR composites for particular applications.

Low-Viscosity Ether-Functionalized Ionic Liquids as Solvents for the Enhancement of Lignocellulosic Biomass Dissolution

Due to the substantial usage of fossil fuels, the utilization of lignocellulosic biomass as renewable sources for fuels and chemical production has been widely explored. The dissolution of lignocellulosic biomass in proper solvents is vital prior to the extraction of its important constituents, and ionic liquids (ILs) have been found to be efficient solvents for biomass dissolution. However, the high viscosity of ILs limits the dissolution process. Therefore, with the aim to enhance the dissolution of lignocellulosic biomass, a series of new ether-functionalized ILs with low viscosity values were synthesized and characterized. Their properties, such as density, viscosity and thermal stability, were analyzed and discussed in comparison with a common commercial IL, namely 1-butyl-3-methylimidazolium chloride (BMIMCl). The presence of the ether group in the new ILs reduces the viscosity of the ILs to some appreciable extent in comparison to BMIMCl. 1-2(methoxyethyl)-3-methylimidazolium chloride (MOE-MImCl), which possesses the lowest viscosity value among the other ether-functionalized ILs, demonstrates an ability to be a powerful solvent in the application of biomass dissolution via the sonication method. In addition, an optimization study employing response surface methodology (RSM) was carried out in order to obtain the optimum conditions for maximum dissolution of biomass in the solvents. Results suggested that the maximum biomass dissolution can be achieved by using 3 weight% of initial biomass loading with 40% amplitude of sonication at 32.23 min of sonication period.

Acetonitrile-Hexane Extraction Route to Pure Sulfonium Salts

A rapid, simple procedure is described for synthesizing trialkyl, dialkylaryl, and alkyldiaryl sulfonium salts that features a selective extraction procedure to access analytically pure sulfonium salts. Alkylation of dialkylsulfides, alkylarylsulfides, and diarylsulfides followed by partitioning between acetonitrile and hexanes efficiently separates nonpolar reactants and byproducts, the usual impurities, to afford analytically pure crystalline and noncrystalline sulfonium salts. The method is efficient, general, and particularly well suited for the preparation of oily sulfonium salts that are otherwise extremely difficult to purify.

Acyclic and Cyclic Alkyl and Ether-Functionalised Sulfonium Ionic Liquids Based on the [TFSI]- and [FSI]- Anions as Potential Electrolytes for Electrochemical Applications

This work provides a study based on acyclic and cyclic sulfonium ionic liquids (ILs) with alkyl and ether-functionality on the cation paired with the bis{(trifluoromethyl)sulfonyl}imide, [TFSI]- , or the bis(fluorosulfonyl)imide, [FSI]- , as the counter anion. Herein, thermophysical characterisation of nine sulfonium-based ILs concerning the density, viscosity and conductivity and thermal properties including phase transition behaviour and decomposition temperature is reported. The electrochemical stability of the ILs was also measured by cyclic voltammetry at a glassy carbon macro-disk electrode. All of the ILs showed low melting point, low viscosity and good conductivity and could serve as potential electrolytes for energy storage devices.

Ionic liquid binary mixtures: how different factors contribute to determine their effect on the reactivity

We studied how mixing ionic liquids affected the rate of the Diels Alder reaction between 9-anthracenemethanol and N-ethylmaleimide.

Cationic sulfonium functionalization renders Znsalens with high fluorescence, good water solubility and tunable cell-permeability

Introducing cationic sulfonium to the Znsalens skeleton circumvents aggregation arising from intermolecular Zn⋯O interactions (found between Zn and the phenoxyl group of another Znsalen molecule).

Thermophysical properties of sulfonium- and ammonium-based ionic liquids

Experimental data for the density, viscosity, refractive index and surface tension of four sulfonium- and ammonium-based Ionic Liquids (ILs) with the common bis(trifluoromethylsulfonyl)imide anion were measured in the temperature range between 288.15 and 353.15 K and at atmospheric pressure. The ILs considered include butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, [N4111][NTf2], tributylmethylammonium bis(trifluoromethylsulfonyl)imide, [N4441][NTf2], diethylmethylsulfonium bis(trifluoromethylsulfonyl)imide, [S221][NTf2], and triethylsulfonium bis(trifluoromethylsulfonyl)imide, [S222][NTf2]. Based on the gathered results and on data taken from literature, the impact of the cation isomerism and of the size of the aliphatic tails, as well as the effect resulting from the substitution of a nitrogen by a sulfur atom as the cation central atom, on the thermophysical properties of sulfonium- and ammonium-based ILs is here discussed. Remarkably, more symmetric cations present a lower viscosity for the same, and sometimes even for higher, alkyl chain lengths at the cation. Additional derivative properties, such as the isobaric thermal expansion coefficient, the surface thermodynamic properties and the critical temperature for the investigated ILs were also estimated and are presented and discussed.