5376-10-3Relevant articles and documents
Monomers and polymers carrying imidazole and benzimidazole groupings, and proton exchange membrane containing the same for the production of a fuel cell
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Page/Page column 6, (2014/10/28)
The invention relates to a monomer (6, 14) carrying an imidazole-type heterocycle (3). According to the invention, the chemical structure of said monomer (6, 14) comprises at least one unit of formula (I) wherein R1 comprises an alkenyl grouping and R2 comprises a grouping for protecting one of the nitrogen atoms of the heterocycle. The invention also relates to a monomer carrying a benzimidazole-type heterocycle, and to protected polymers obtained from said monomers, deprotected polymers produced by the protected polymers, a proton exchange membrane based on deprotected polymers, and a fuel cell provided with said membrane. Furthermore, the invention relates to methods for producing the above-mentioned monomers and polymers.
Syntheses, protonation constants and antimicrobial activity of 2-substituted N-alkylimidazole derivatives
Kleyi, Phumelele,Walmsley, Ryan S.,Gundhla, Isaac Z.,Walmsley, Tara A.,Jauka, Tembisa I.,Dames, Joanna,Walker, Roderick B.,Torto, Nelson,Tshentu, Zenixole R.
, p. 231 - 238 (2013/01/15)
A series of N-alkylimidazole-2-carboxylic acid, N-alkylimidazole-2- carboxaldehyde and N-alkylimidazole-2-methanol derivatives [alkyl = benzyl, methyl, ethyl, propyl, butyl, heptyl, octyl and decyl] have been synthesized and the protonation constants determined. The antimicrobial properties of the compounds were tested against Gram-negative (Escherichi coli), Gram-positive (Staphylococcus aureus & Bacillus subtilis subsp. spizizenii) bacterial strains and yeast (C. albicans). Both the disk diffusion and broth microdilution methods for testing the antimicrobial activity showed that N-alkylation of imidazole with longer alkyl chains and the substitution with low pKa group at 2-position resulted in enhanced antimicrobial activity. Particularly, the N-alkylimidazole-2-carboxylic acids exhibited the best antimicrobial activity due to the low pKa of the carboxylic acid moiety. Generally, all the N-alkylimidazole derivatives were most active against the Gram-positive bacteria [S. aureus (MIC = 5-160 μg mL-1) and B. subtilis subsp. spizizenii (5-20 μg mL-1)], with the latter more susceptible. All the compounds showed poor antimicrobial activity against both Gram-negative (E. coli, MIC = 0.15 to >2500 μg mL-1) bacteria and all the compounds were inactive against the yeast (Candida albicans).
Synthesis and properties of new fluorinated polymers bearing pendant imidazole groups for fuel cell membranes operating over a broad relative humidity range
Frutsaert, Guillaume,Delon, Louis,David, Ghislain,Ameduri, Bruno,Jones, Deborah J.,Glipa, Xavier,Roziere, Jacques
experimental part, p. 223 - 231 (2010/11/04)
New alternating copolymers comprising a chlorotrifluorinated backbone and midazole-terminated pendant ethylene oxide groups have been prepared with a view to their use as a component of proton-conducting membranes in polymer electrolyte fuel cells. A vinyl ether containing an imidazole (Imi) function protected by a benzyl group (BVI) was first synthesized in a three-step reaction. It was then copolymerlzed in solution with chlorotrifluoroethylene (CTFE) by conventional radical copolymerization leading to alternating poly(BVI-altCTFE) copolymers in good yields. Deprotection of the benzyl group under hydrogen produced a chlorotrifluorinated poly (Imi-alt-CTFE) copolymer. The polymer was subsequently used to form blend membranes with sulfonated poly(ether ether ke-tone) (sPEEK). The conductivity of blend membranes of poly (Imi-alt-CTFE) with sPEEK lies in the range of 4-10 mS cm-1 at 40-70 °C and, for blend membranes rich in poly(Imi-alt-CTFE), is little dependent on relative humidity between 30 and 100%. It Is surmised that the polymer and membrane composition favor microstructural phase separation into chlorotrifluorlnated polymer backbone domains and regions in which imidazole groups are clustered.
