433337-24-7Relevant articles and documents
First observation for dynamic solvent effect in ionic liquids
Kitaoka, Satoshi,Nobuoka, Kaoru,Miura, Junji,Ohga, Yasushi,Ishikawa, Yuichi
, p. 385 - 387 (2016/05/09)
We observed pressure effects on the rate of thermal fading of colored chromene 1 photochemically generated from 2 in ionic liquids. The reaction rates were retarded with increasing pressure in [C4-mim][CS], [bzl-mim][Tf2N], and [mnp-mim][Tf2N], whereas the reaction rate increased with pressures in [C4- mim][Tf2N]. These pressure-induced retardations, so-called dynamic solvent effects, result from the slow thermal fluctuations of solvents.
Isoamyl acetate synthesis in imidazolium-based ionic liquids using packed bed enzyme microreactor
Cvjetko, Marina,Vorkapi?-Fura?, Jasna,?nidar?i?-Plazl, Polona
experimental part, p. 1344 - 1350 (2012/09/08)
The acylation of isoamyl alcohol with acetic anhydride catalyzed by immobilized Candida antarctica lipase B was studied in ionic liquids (ILs) based on quaternary imidazolium cations with alkyl, alkenyl, alkynyl, benzyl, alkoxyl or N-aminopropyl side chains. Among the tested ILs, the highest enzyme activity together with the highest isoamyl acetate yield were obtained in [C 7mmim][Tf2N]. No loss of lipase B activity was observed during one-month incubation in this hydrophobic IL without the presence of substrates. Isoamyl acetate synthesis using [C7mmim][Tf2N] as solvent was further studied in a continuously operated miniaturized enzymatic packed bed reactor at various flow rates and temperatures. Up to 92% isoamyl acetate yield could be obtained within 15 min by using 0.5 M acetic anhydride and 1.5 M isoamyl alcohol inlet concentrations at 55°C, corresponding to the volumetric productivity of 61 mmol l-1 min -1, which to the best of our knowledge is the highest reported so far for this reaction. No decrease in productivity was experienced during the subsequent runs of continuous microbioreactor operation performed within 14 consecutive days. The benefits of reactor miniaturization along with the green solvent application were therefore successfully exploited for the development of a sustainable flavour ester production.
A simple access to metallic or onium bistrifluoromethanesulfonimide salts
Arvai, Roman,Toulgoat, Fabien,Langlois, Bernard R.,Sanchez, Jean-Yves,Médebielle, Maurice
experimental part, p. 5361 - 5368 (2009/12/01)
Numerous salts of the (CF3SO2)2N- anion, called TFSI, were prepared according to an original one-pot procedure. First, N-benzyl trifluoromethanesulfonimide (N-benzyl triflimide) was treated with ethanol to form
Improved solubilization of pyromellitic dianhydride and 4,4′-oxydianiline in ionic liquid by the addition of zwitterion and their polycondensation
Tamada, Masahiro,Hayashi, Takahiro,Ohno, Hiroyuki
, p. 1553 - 1557 (2008/02/03)
Three different ionic liquids were prepared and examined as solvents for polyimide synthesis. The solubility of 4,4′-oxydianiline and pyromellitic dianhydride as starting materials in ionic liquids was first evaluated, and then their polycondensation was carried out. Although these starting materials were hardly soluble in 1-benzyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide (3), addition of imidazolium type zwitterion, 1-(1-butyl-3-imidazolio)butane-4-sulfonate (ZI), certainly improved their solubility. When 3 containing 40 mol % ZI was used, nothing was phase separated from this mixed solution containing both starting materials after cooling down to room temperature. After preparing prepolymer in 3 containing 40 mol % of ZI at room temperature, polycondensation was carried out in the same solution at 100, 200, and then 300 °C for every 1 h to obtain polyimide. An inherent viscosity of the obtained polyimide (0.05 g in 10 ml concentrated sulfuric acid) was 1.3 dL g-1, higher than that prepared in only 3 (0.9 dL g-1). The higher average molecular weight of the polyimide was attributed to the improved solubility of the starting materials by the addition of ZI that enabled the preparation of the prepolymer, poly(amide acid), without heating before imidation.
An acidity scale of 1,3-dialkylimidazolium salts in dimethyl sulfoxide solution
Chu, Yuan,Deng, Hui,Cheng, Jin-Pei
, p. 7790 - 7793 (2008/02/13)
(Chemical Equation Presented) Equilibrium acidities of 16 1,3-dialkylimidazolium-type ionic liquid (IL) molecules (1-16) were systematically measured by the overlapping indicator method at 25°C in dimethyl sulfoxide (DMSO) solution. The pKa values were observed to range from 23.4 for IL 12 to 19.7 for IL 6 (Tables 1 and 2), responding mainly to structural variations on the cation moiety. Excellent agreement between the spectrophotometrically determined pKa and that derived from NMR titration for 1,3,4,5-tetramethylimidazolium bis(trifluoromethanesulfonyl)imide (12) and the close match of the obtained pK values with the reported data in literature provide credence to the acidity measurements of the present work. The substituent effects at the imidazolium ring and the effects of counterions on the acidities of ionic liquids are discussed.
Expanding the polarity range of ionic liquids
Dzyuba, Sergei V.,Bartsch, Richard A.
, p. 4657 - 4659 (2007/10/03)
The polarity of several [X-mim]NTf2 ionic liquids, as measured with solvatochromic dyes, Reichardt's dye and Nile Red, may be varied over a wide range by attachment of functional group-containing substituents (X) to the imidazolium cation.
