Perfluorinated 1,2,3‐ and 1,2,4‐Triazolium Ionic Liquids

Abstract

Dialkyl triazolium triflimides with perfluorinated side chains were prepared as hydrophobic ionic liquids (ILs) for surface impregnation. The key feature of the new materials are relatively short perfluorohexyl residues (nC6F13 = RF) as the fluorinated part of the cations, making the target compounds beneficial alternatives to established products because of their enhanced degradability and therefore lower bioaccumulativity. As heterocyclic scaffold, either 1,2,3‐triazole or 1,2,4‐triazole were chosen. As the two alkyl moieties, either two RFCH2CH2 groups or one RFCH2CH2 and one Et residue were applied. The diethyl congeners were also prepared. Fluorinated starting materials were RFCH2CH2OTf as alkylating reagent or RFCH2CH2N3 as 1,3‐dipole for a copper catalyzed cycloaddition (CuAAC) with trimethylsilyl acetylene. After sequential CuAAC and alkylation reactions, the triflimide salts were finally obtained from the intermediate iodides or triflates with the aid of an ion exchange resin. Out of 14 triazolium salts prepared, four compounds have finally been identified as hydrophobic ILs (contact angles between 85° and 100° with mp. < 100 °C), being promising materials for surface impregnation: the 1,2,3‐triazolium triflate and triflimide with two fluorinated alkyl residues, and the 1,2,4‐triazolium triflimides (two regioisomers) with one fluorinated alkyl residues and one ethyl group.

Dissolving Cellulose in 1,2,3-Triazolium- and Imidazolium-Based Ionic Liquids with Aromatic Anions

“…Microcrystalline cellulose with a particle size of 20 µm and a molar mass of 37 kg mol −1 (as determined by viscosimetry) was purchased from Sigma Aldrich. [24] and ethyl bromide [19]. 1,2,3Triazole (0.22 mol) was dissolved in a suspension of potassium carbonate (0.43 mol) in 150 mL THF.…”

“…1-ethyl-3-methyltriazolium benzoate [EMTr][OBz] and 1-ethyl-3-methyltriazolium salicylate [EMTr][OSc] were prepared from 1-ethyl-3-methyl-1,2,3-triazolium bromide ([EMTr][Br]). The synthesis involved an alkylation with methyl iodide [ 24 ] and ethyl bromide [ 19 ]. 1,2,3Triazole (0.22 mol) was dissolved in a suspension of potassium carbonate (0.43 mol) in 150 mL THF.…”

“…Last year, we proposed triazolium-based ILs as a novel class of cellulose solvents [38]. This class of ILs has been discussed in the literature earlier [1,19,21,42,43], but had never been applied to dissolve cellulose before. The 1,2,3-triazolium cation is very similar to imidazolium; only a C-H fragment in the aromatic ring is replaced by a nitrogen atom.…”

“…In principle known for more than 100 years now [ 16 ], ILs are a class of organic salts with a melting point below 100 °C. They often feature properties such as low vapor pressure, low toxicity, and good thermal stability [ 17 , 18 , 19 ] and possess a wide scope of applications in scientific and industrial fields [ 20 , 21 ], medicine [ 22 , 23 ], electrochemistry [ 24 ], as solvents [ 12 ], and in organic synthesis [ 18 ]. In order to dissolve cellulose, a solvent needs to break up the hydrogen bond network between the polymer strands [ 25 ] and replace it by hydrogen bonds to the solvent [ 8 ].…”

Highly‐fluorinated Triaminocyclopropenium Ionic Liquids

“…These have been attached to imidazolium and triazolium cations. [23,24] FC-ILs with more than one fluorinated alkyl group are only known for classes II 2 [10,16,25,26] (imidazolium, triazolium, pyridinium, ammonium and phosphonium) and II 3 (phosphonium). [27] Alpers et al also reported some dicationic diammonium and diphosphonium ILs with two fluorinated alkyl groups.…”