1-octyl-3-methylimidazolium-hexafluorophosphate and 1-butyl-3-methylimidazolium-tetrafluoroborate

Ionic liquids (ILs) have been considered as "green" substitutes for traditional organic solvents in many existing biological and chemical areas. However, they have high solubility and poor biodegradability in water, suggesting that they could become persistent chemical pollutants in aquatic environment. The ability of two widely used imidazolium-based ILs to affect the growth and physiological characteristics of a marine diatom (Phaeodactylum tricornutum) was investigated in this study. The diatom was exposed to different concentrations of 1-butyl-3-methylimidazolium tetrafluoroborate ([C

Topics: China; Chlorophyll; Chlorophyll A; Diatoms; Environmental Monitoring; Imidazoles; Ionic Liquids; Lipid Peroxidation; Photosynthesis; Reactive Oxygen Species; Superoxide Dismutase; Water Pollutants, Chemical

The main goal of this study was to investigate the toxicity of the imidazolium-based ionic liquids (ILs), [bmim][BF4] (1-butyl-3-methylimidazolium tetrafluoroborate) and [omim][BF4] (1-octyl-3-methylimidazolium tetrafluoroborate), in battery of standard aquatic toxicity test organisms. Specifically, exposure of the algae Scenedesmus rubescens, crustaceans Thamnocephalus platyurus and Artemia franciscana, rotifers Brachionus calyciflorus and Brachionus plicatilis and bivalve Mytilus galloprovincialis to different concentrations of [bmim][BF4], [omim][BF4] and/or a binary mixture of [bmim][BF4]-[omim][BF4] (1:1) with or without acetone (carrier solvent), revealed that solvent can differentially mediate ILs' toxic profile. Acetone's ability to differentially affect ILs' cation's alkyl chain length, as well as the hydrolysis of [BF4(-)] anions was evident. Given that the toxic potency of the tested ILs seemed to be equal or even higher (in some cases) than those of conventional organic solvents, the present study revealed that the characterization of imidazolium-based ILs as "green solvents" should not be generalized, at least in case of their natural occurrence in mixtures with organic solvents, such as acetone.

Topics: Acetone; Animals; Anions; Artemia; Drug Interactions; Imidazoles; Ionic Liquids; Mytilus; Organic Chemicals; Rotifera; Scenedesmus; Solvents; Toxicity Tests

Metal particles of silver (Ag) were synthesized by the photoreduction of silver perchlorate (AgClO(4)) in water-in-ionic liquid (ILs) microemulsions consisting of Tween 20, water and ionic liquids. The ILs were tetrafluoroborate anions associated with the cations 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF(4)]) and 1-octyl-3-methylimidazolium tetrafluoroborate ([OMIm][BF(4)]). The time evolution of Ag particle formation by photoreduction using UV-irradiation was investigated by UV-Vis, cryo-TEM, extended X-ray absorption fine structure (EXAFS) and small angle X-ray scattering (SAXS) measurements. The average diameter of the metallic Ag particles prepared in the water-in-[BMIm][BF(4)] and water-in-[OMIm][BF(4)] microemulsions was estimated from TEM to be 8.9 and 4.9nm, respectively, which was consistent with that obtained from the SAXS analysis. Using Guinier plots in a low q-range (<0.16nm(-1)), we demonstrate that the average diameter of the water droplets that consisted of aggregates of ionic precursors of AgClO(4) before reduction and Ag particles after reduction, in the microemulsions, was estimated to be about 20-40nm. The diameter of the water droplets increased as a function of photoreduction time because of the formation of Ag particles and their aggregates. EXAFS analysis indicated that Ag(+) ions were completely reduced to Ag(0) atoms during the photoreduction, followed by the formation of larger Ag particles.

Topics: Emulsions; Imidazoles; Ionic Liquids; Metal Nanoparticles; Particle Size; Perchlorates; Polysorbates; Scattering, Small Angle; Silver; Silver Compounds; Water; X-Ray Diffraction

A comparative study of peak shape, elution behavior, elution strength and resolution of seven beta-blockers (acebutolol, alprenolol, labetalol, metoprolol, nadolol, pindolol and propranolol) chromatographed with aqueous-organic mobile phases containing additives such as the ionic liquid (IL) 1-butyl-3-methylimidazolium (BMIM BF(4)) or triethylamine (TEA) is performed using a conventional reversed-phase Kromasil C(18) column and isocratic elution. The efficiencies and asymmetry factors achieved for the group of beta-blockers in the Kromasil C(18) column improve when the cationic modifiers are added to the aqueous-organic mobile phase as competing additives for the silanol active sites. BMIM BF(4) is a significantly better additive compared to TEA. The improvement is more notably for the asymmetry factor, BMIM BF(4) allowing to obtain higher plate numbers than TEA at the same concentration. The effects of both modifiers on elution strength and retention factors are, however, different. TEA decreases the solute retention factors when BMIM BF(4) does not change them significantly. Using other additives taken in the IL family such as 1-butyl-3-methylimidazolium hexafluorophosphate and 1-octyl-3-methylimidazolium tetrafluoroborate (OMIM BF(4)), it is shown that the silanol screening effect is always observed, due to the IL cation, when it is possible to increase or to decrease the solute retention factors playing with the hydrophobic nature or chaotropic character of its anion.

Topics: Adrenergic beta-Antagonists; Borates; Chromatography, High Pressure Liquid; Ethylamines; Imidazoles; Ions