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Physicochemical and Solution Properties of Quaternary-Ammonium-Salt-Type Amphiphilic Trimeric Ionic Liquids

Risa Kawai, Shiho Yada, Tomokazu Yoshimura

Phys Chem Chem Phys. 2019 Dec 7;21(45):25065-25071.

PMID: 31690900

Abstract:

The quaternary-ammonium-salt-type amphiphilic compounds 3Cntris-s-Q X (star-type; carbon number between the central amino and ammonium groups s = 2, 3) and 3Cnlin-3-Q X (linear-type; carbon number between the hydrophilic groups s = 3), where n represents the alkyl chain length (n = 8, 10, 12, 14) and X represents a counterion [hexafluorophosphate, trifluoromethanesulfonate (OTf), bis(fluorosulfonyl)amide (FSA), and bis(trifluoromethanesulfonyl)amide (NTf2)], were synthesized. Except for 3C12tris-3-Q OTf, these trimeric compounds presented melting points lower than 100 °C and therefore are defined as ionic liquids. Among them, 3Cntris-3-Q NTf2 (n = 8, 12, 14) and 3Cnlin-3-Q NTf2 (n = 8, 10) presented melting points lower than 0 °C. The melting points of the amphiphilic trimeric ionic liquids (n = 8, 10), which were lower for the star- than for the linear-type compounds, were higher than those of the corresponding monomeric compounds but lower than those of the corresponding gemini samples. Moreover, the amphiphilic trimeric ionic liquids exhibited higher conductivities and lower viscosities than the corresponding gemini ionic liquids, while the star-type trimeric ionic liquids presented lower conductivities and higher viscosities than those of the linear-type compounds. The amphiphilic trimeric ionic liquids also readily adsorbed at the air/water interface and oriented themselves to form micelles in aqueous solution. This aggregation behavior was not observed in the monomeric and gemini ionic liquids.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
AP38542948 Ammonium trifluoromethanesulfonate Ammonium trifluoromethanesulfonate 38542-94-8 Price
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