Organic Preparative Section

Becker, H. B.; Berger, W.; Domschke, Günter; Fanghänel, E.; Faust, Jürgen; Fischer, M.; Gentz, Frithjof; Gewald, K.; Gluch, Reiner; Mayer, Roland; Müller, Klaus Robert; Pavel, Dietrich; Schmidt, Hermann; Schollberg, K; Schwetlick, K.; Zeppenfeld, Günter

doi:10.1016/b978-0-201-05504-7.50008-2

Cited by 5 publications

(6 citation statements)

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“…Crosslinked 5′MS‐PBI remained stable, but the IR spectra reveal new bands at 1687 and 1572 cm −1 , indicating the presence of amides (C═O and NH), and a broad band at 1610–1626 cm −1 , which is in the range of the N─H deformation of amines. [ 30 ] Assuming that the crosslinked, uncharged imidazole rings are the preferred breaking points, we suggest that the imidadzole rings open preferentially into the secondary amide, not into the tertiary amide. Although the tertiary amides obtained from alkaline degradation of methylated PBI have some stability and exist as an observable species, they degrade further, and membranes get brittle and break into pieces.…”

Section: Resultsmentioning

confidence: 96%

“…Another potential pathway is a nucleophilic substitution reaction on the benzylic position, which would not break the polymer backbone, but destroy the crosslinks and by this transfer 5MS-PBI into MS-PBI over time. Finally, sulfonic acid groups can be substituted by hydroxide groups -synthetically, this reaction is done at temperatures ≈300 °C in molten KOH, [28] but is discussed as a potential degradation reaction for sulfonated quinones. [29] Although MS-PBI strongly degraded, IR analysis (Figure S4, Supporting Information) showed no significant changes.…”

Section: Alkaline Stabilitymentioning

confidence: 99%

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Quaternary Ammonium‐Free Membranes for Water Electrolysis with 1 m KOH

Dayan,

Trisno,

Yang

et al. 2023

Advanced Energy Materials

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While anion exchange membrane (AEM) water electrolysis has many advantages, its commercialization is impeded by the low alkaline stability of most AEM, due to the fragility of quaternary ammonium groups. Ion solvating membranes (ISM) can be an alternative, but so far require high alkaline concentrations. Here, it is shown that sulfonation of polybenzimidazole results in ISM which swell strongly in 1 m KOH. Crosslinking with dibromoxylene controls the swelling, and after activation conductivities of >100 mS cm−1 can be reached in 1 m KOH. Stability in 1 m KOH at 80 °C is excellent: Conductivity remains unchanged and tensile strength and Young's modulus remains high over the test period of a half year. In an electrolyzer operating with 1 m KOH feed solution at 80 °C, a stable performance is achieved for over 500 h test without failure, suggesting that the high alkaline stability observed in ex situ tests is also achieved in the electrolyzer.

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Section: Resultsmentioning

confidence: 96%

Section: Alkaline Stabilitymentioning

confidence: 99%

Quaternary Ammonium‐Free Membranes for Water Electrolysis with 1 m KOH

Dayan,

Trisno,

Yang

et al. 2023

Advanced Energy Materials

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“…2,5‐Furandicarboxylic acid dimethylester was prepared in a classical esterification [ 62 ] with methanol and sulfuric acid as catalyst. Thus, FDCA (234.14 g, 1.5 mol) was dissolved in MeOH (610 mL, 15 mol) and concentrated sulfuric acid (23 mL, 0.6 mol) was added slowly under stirring.…”

Section: Methodsmentioning

confidence: 99%

Partially Bio‐Based Polyester Bead Foams via Extrusion Foaming of Poly(butylene terephthalate)/Poly(butylene furanoate) Blends

Mielke,

Pospiech,

Kuhnigk

et al. 2023

Macro Materials & Eng

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The interest in bio‐based alternatives to classical polyesters such as poly(ethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT) is steadily growing to achieve a more sustainable approach to polymer materials. In this study, PBT/poly(butylene furanoate) (PBF) blends are prepared, characterized and extrusion foamed. PBF as a bio‐based polyester offers two advantages. The ecological footprint of the material is reduced, and additionally, it can be used in Diels‐Alder reactions at the blend surface to support fusion of the foamed beads. The blending behavior of the polyesters is investigated using samples prepared in a microcompounder, particularly focused on the miscibility of the blends and transesterification reactions. The blends are thermodynamically immiscible but show a certain degree of transesterification according to nuclear magnetic resonance (NMR) spectroscopy. The morphology of blend beads produced by an extrusion foaming process is analyzed regarding their cell density, cell size distribution, and open‐cell content. It is shown that PBF has a positive effect on the bead foam morphology. The use of a bifunctional linker designed for chemical fusion of the bead surfaces allows to obtaining of molded parts, in contrast to beads containing pure PBT.

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“…2-Piperidone (1). Cyclopentanone oxime was dried over phosphorus pen-toxide and subjected to Beckmann rearrangement in concentrated H2SO4 to give 2-piperidone (δ-valerolactam) (Becker et al, 1973). HR-MS: m /z M + 99.066, calcd.…”

Section: Reference Compoundsmentioning

confidence: 99%

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Burger

Smit

Spies

et al. 2001

Journal of Chemical Ecology

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In a study aimed at the chemical characterization of constituents of the ventral gland secretion of the male dwarf hamster, Phodopus sungorus sungorus, 48 compounds, including saturated alcohols, saturated and unsaturated ketones, saturated and unsaturated straight-chain carboxylic acids, iso-and an-teisocarboxylic acids, 3-phenylpropanoic acid, hydroxyesters, 2-piperidone, and some steroids were identified in the secretion.The position of the double bonds in γ -icosadienyl-γ -butyrolactone and γ -henicosadienyl-γ -butyrolactone, and the position of methylbranching in seven C16 -C21 saturated ketones could not be established. Several constituents with typically steroidal mass spectra also remained unidentified. The female dwarf hamster's ventral gland either does not produce secretion or produced so little secretion that it was impossible to collect enough material for analysis.

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Organic Preparative Section

Cited by 5 publications

References 0 publications

Quaternary Ammonium‐Free Membranes for Water Electrolysis with 1 m KOH

Quaternary Ammonium‐Free Membranes for Water Electrolysis with 1 m KOH

Partially Bio‐Based Polyester Bead Foams via Extrusion Foaming of Poly(butylene terephthalate)/Poly(butylene furanoate) Blends

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