Synthesis of new fluorinated imidazolium ionic liquids and their prospective function as the electrolytes for lithium-ion batteries

Highly-fluorinated Triaminocyclopropenium Ionic Liquids

A series of highly‐fluorinated triaminocyclopropenium salts, with up to six fluorous groups, were prepared and their properties as ionic liquids investigated. Reaction of pentachlorocyclopropane or tetrachlorocyclopropene with bis(2,2,2‐trifluoroethyl)amine, HN(CH₂CF₃)₂, occurs in the presence of a trialkylamine, NR₃, to give cations with two fluorinated amino groups, [C₃(N(CH₂CF₃)₂)₂(NR₂)]⁺ (R=Et, Pr, Bu, Hex), with traces of [C₃(N(CH₂CF₃)₂)₃]⁺. Use of appropriate reagent ratios and reaction times and subsequent addition of a dialkylamine, HNR'R”, gives cations with one fluorinated amino group, [C₃(N(CH₂CF₃)₂)(NR₂)(NR'R”)]⁺ ((NR₂)(NR'R”)=(NBu₂)₂, (NEt₂)(NPr₂), (NBu₂)(NBuMe)). These cations were isolated as chloride salts and some of these were converted to bistriflamide, dicyanamide and triflate salts to provide ionic liquids. These salts were characterised by thermal (DSC and TGA) measurements and miscibility/solubility properties (determined in a range of solvents). Ionic liquids (ILs) were also characterised by density, viscosity and conductivity measurements where possible. X‐ray diffraction studies of chloride salts showed the formation of fluorous regions and more hydrophilic ionic regions in the solid state.

Fluorinated Poly(ionic liquid) Diblock Copolymers Obtained by Cobalt-Mediated Radical Polymerization-Induced Self-Assembly

Poly(ionic liquid)s (PILs) have attracted considerable attention as innovative single-ion solid polyelectrolytes (SPEs) in substitution to the more conventional electrolytes for a variety of electrochemical devices. Herein, we report the precise synthesis, characterization, and use as single-ion SPEs of a novel double PIL-based amphiphilic diblock copolymer (BCP), i.e., where all monomer units are of N-vinyl-imidazolium type, with triethylene glycol pendant groups in the first block and a statistical distribution of N-vinyl-3-ethyl- and N-vinyl-3-perfluorooctyl-imidazolium bromides in the second block. BCP synthesis is achieved directly in water by a one-pot process, by cobalt-mediated radical polymerization-induced self-assembly (CMR-PISA). A subsequent anion exchange reaction substituting bis(trifluoromethylsulfonyl)imide (Tf₂N^-) for bromide (Br^-) counter-anions leads to PIL BCPs with two different lengths of the first block. They demonstrate ionic conductivity σ_DC = 1-3 × 10^-7 S cm^-1, as determined by broadband dielectric spectroscopy at 30 °C (under anhydrous conditions), and exhibit wide electrochemical stability (up to 4.8 V versus Li⁺/Li) and form free-standing films with mechanical properties suited for SPE applications (Young's modulus = 3.8 MPa, elongation at break of 250%) as determined by stress/strain experiments.

Brønsted acidic ionic liquid-promoted direct C3-acylation of N-unsubstituted indoles with acid anhydrides under microwave irradiation

A green and efficient method for the synthesis of 3-acylindoles using a Brønsted acidic ionic liquid under microwave irradiation has been developed.

Novel thiosalicylate-based ionic liquids for heavy metal extractions

This study aims to develop novel ammonium and phosphonium ionic liquids (ILs) with thiosalicylate (TS) derivatives as anions and evaluate their extracting efficiencies towards heavy metals in aqueous solutions. Six ILs were synthesized, characterized, and investigated for their extracting efficacies for cadmium, copper, and zinc. Liquid-liquid extractions of Cu, Zn, or Cd with ILs after 1-24h using model solutions (pH 7; 0.1M CaCl2) were assessed using flame atomic absorption spectroscopy (F-AAS). Phosphonium-based ILs trihexyltetradecylphosphonium 2-(propylthio)benzoate [P66614][PTB] and 2-(benzylthio)benzoate [P66614][BTB] showed best extraction efficiency for copper and cadmium, respectively and zinc was extracted to a high degree by [P66614][BTB] exclusively.