Aromatic Esters, Carbinols, and Derivatives Thereof with Perfluorohexyl Residues as Alternatives to Perfluoroalkanecarboxylic and ‐sulfonic Acids

Muesmann²,

Temme³

et al. 2018

Eur J Org Chem

Self Cite

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.

Section: Introductionmentioning

confidence: 99%

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

Muesmann²,

Temme³

et al. 2018

Eur J Org Chem

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“…The synthesis of pyridinium compounds proceeded from the acid chloride, which was obtained from 3,5‐pyridine dicarboxylic acid 4 with an excess of SOCl 2 . Conversion with R F CH 2 CH 2 OH (R F = n F 13 C 6 ) without additional solvent furnished the fluorinated diester 5 in 93 % yield, as reported before (Scheme ) . Alkylation with an excess of MeI and EtI, respectively, required relatively high concentration (1 mol/L in acetone) and temperature (150 °C); therefore, the reaction was performed in a tightly closed reaction vial.…”

Section: Resultsmentioning

confidence: 71%

“…Contact angle measurements were performed with a Contact Angle System OCA, model 15plus from dataphysics and a Teli ccd camera, model CS8620C1. The droplet volume was 9 µL and photograph was taken after 2 s. Diester 5 and n C 6 F 13 CH 2 CH 2 OTf ( 7 ) were prepared according to reported protocols. All other starting materials were commercially available.…”

Section: Methodsmentioning

confidence: 99%

Perfluorinated Pyridinium and Imidazolium Ionic Liquids

Schmidtmann

Muesmann³

et al. 2017

Eur J Org Chem

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Ionic liquids with perfluorinated side chains were prepared as hybrid materials for surface impregnation. For the cationic part, methyl and ethyl pyridinium as well as imidazolium scaffolds were used. The anions investigated were hydroxide, acetate, trifluoroacetate, triflate, triflimide, chloride, bromide, iodide, hydrogensulfate, and perfluorododecanoate. A key feature of this investigation is the finding that the use of relatively short perfluorohexyl residues as the fluorinated part of the salts is beneficial for the target compounds compared with established products, because of their lower bioaccumulativity. One compound yielded single crystals that were suitable for X‐ray structure analysis, revealing a layered structure with relatively well‐resolved, hard ionic domains alternating with disordered, soft perfluorinated layers. The wettability of all 30 materials was investigated by water contact angle measurements of a thin film on a glass surface. In two cases, promising contact angles (130° and 140°) were observed, indicating that the products might be suitable candidates for the impregnation of surfaces.

“…In the course of global efforts to replace PFOA (C 7 F 15 CO 2 H) and PFOS (C 8 F 17 SO 3 H) as surface active ingredients, many industrial manufacturers have begun investigations on alternative resins with shorter perfluorinated alkyl chains, hence, enhanced degradability and therefore low bioaccumulativity. Our contribution to this field is the development of novel ionic liquids with ammonium and phosphonium cations carrying perfluorinated n-hexyl residues ('R F '), which were introduced by n-C 6 F 13 CH 2 CH 2 OTf (11) and n-C 6 F 13 CH 2 CH 2 I (19) as alkylating reagents.…”

Section: Paper Syn Thesismentioning

confidence: 99%

“…10 As a manufacturer of water repellent textile coatings, we are also aiming at identifying new compounds with shorter perfluoroalkyl side chains. 11 In particular fluorinated ionic liquids have come into focus as part of our research. Perfluorinated solvents 12 and ionic liquids 13 are socalled neoteric solvents, which are often associated with sustainable processes and green chemistry, 14 although their benefits are sometimes critically discussed.…”

mentioning

confidence: 99%

Perfluorinated Ammonium and Phosphonium Ionic Liquids

Muesmann²,

Temme³

et al. 2018

Synthesis

Self Cite

Ammonium and phosphonium ionic liquids with perfluorinated side chains were prepared as hybrid materials for surface impregnation. Melting points of the triflimide salts range up to 95 °C. The key feature of this investigation are relatively short perfluorohexyl residues 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. In the ammonium series, pyrrolidinium, piperidinium, morpholinium triflimides as well as the dication derived from DABCO were prepared. Mono-phosphonium triflimides were obtained from triphenyl- and diphenylphosphane. Diphosphonium bistriflimides were obtained from bis(diphenylphosphano)alkanes, Ph2P(CH2)nPPh2 with n = 2–5. As alkylating reagents, n-C6F13CH2CH2OTf and n-C6F13CH2CH2I were applied.