99257-94-0Relevant articles and documents
High-temperature proton exchange membranes from ionic liquid absorbed/doped superabsorbents
Tang, Qunwei,Wu, Jihuai,Tang, Ziying,Li, Yan,Lin, Jianming
, p. 15836 - 15844 (2012)
The development of high-temperature proton exchange membranes (HTPEMs) operated over 120 °C under anhydrous conditions is pursued worldwide in order to solve some core problems of current PEM fuel cells based on Nafion (CO tolerance, improved kinetics, water management, etc.). In the current work, two classes of HTPEMs based on absorbing and doping of the protic ionic liquid, 1-methylimidazolium trifluoromethanesulfonate ([MIm][Tfo]), into a 3D framework of poly(acrylic acid)-poly(ethylene glycol) (PAA-PEG) superabsorbent are successfully synthesized. The resultant membranes show high proton conductivity, good thermal stability and excellent mechanical strength due to the unique absorption property and interpenetrated polymer network of PAA-PEG, and good conduction of [MIm][Tfo]. Proton conductivities as high as 40.4 and 19.4 mS cm-1 at 200 °C under anhydrous conditions are obtained in [MIm][Tfo] doped and absorbed PAA-PEG membranes, respectively. The long-term stability of the superabsorbent-based membranes at high-temperatures, in combination with simple preparation, low cost, scalable host and proton conductor, demonstrates the potential use of these materials in HTPEMs.
Imidazolium-based protic ionic liquids with perfluorinated anions: Influence of chemical structure on thermal properties
Fatyeyeva, K.,Kobzar, Ya. L.,Marais, S.,Martin, A.,Oulyadi, H.,Prykhodko, Y.
, (2021/11/09)
The influence of the cation chemical structure, namely its side chain, on the thermal properties of imidazolium-based protic ionic liquids (PILs) with different perfluorinated anions (trifluoromethanesulfonimide (TFSI), trifluoromethanesulfonic (TFS), and trifluoroacetic (TFA) acids) was studied. With that purpose, twenty-one PILs with various alkyl (methyl-, ethyl-, butyl- and vinyl-) and fluorinated (-CH2CF3, -CH2CHF2, and -CH2CH2F) side chains were successfully synthesized. Special attention was paid to an optimization of their synthesis conditions. The structure of synthesized fluorinated and alkyl-substituted PILs was confirmed by means of nuclear magnetic resonance (NMR) analysis (1D: 1H, 19F, 13C and 2D: 1H – 19F HOESY experiments) and Fourier transform infrared (FTIR) spectroscopy, while PILs thermal behavior was determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) in dynamic and isothermal modes. The correlation between the PILs chemical structure and their thermal stability was established. It has been found that an increase of the length of alkyl side chain (methyl- 2F 2 3) leads to a PIL with a higher crystallinity (a higher melting point temperature) and a lower thermal stability. Thus, the best performance in terms of the thermal stability was reached for monofluorinated- (-CH2F) and butyl-TFSI PILs in liquid state: 370 °C and 400 °C, respectively, while the lowest thermal stability was obtained for trifluorinated- (-CF3) and vinyl-TFA PILs in solid state: 145 °C and 129 °C, respectively.
Production of lactide
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Paragraph 0138-0139, (2016/10/20)
PROBLEM TO BE SOLVED: To overcome defects in use of a tin compound catalyst to obtain a lactide having high optical purity and chemical purity in a lactide production by depolymerization/cyclization of lactic acid oligomer. SOLUTION: The method for production of lactide is characterized by heating the lactic acid oligomer under reduced pressure atmosphere in the presence of a specific organic onium salt and depolymerizing/cyclizing to generate the lactide. COPYRIGHT: (C)2012,JPO&INPIT
