Proton conduction mechanisms in the phosphoric acid–water system (H4P2O7–H3PO4·2H2O): a 1H, 31P and 17O PFG-NMR and conductivity study

2017 ◽  
Vol 19 (1) ◽  
pp. 587-600 ◽  
Author(s):  
Jan-Patrick Melchior ◽  
Klaus-Dieter Kreuer ◽  
Joachim Maier

The exceptionally high structural proton conductivity in neat phosphoric acid (H3PO4), which is closely related to the topology of its frustrated hydrogen bond network, is a singularity in that its contribution to the total ionic conductivity decreases with both increasing and decreasing water content.

1995 ◽  
Vol 73 (8) ◽  
pp. 1294-1297 ◽  
Author(s):  
Yoshikata Koga ◽  
Virginia J. Loo ◽  
Kataryna T. Puhacz

Ionic conductivities of HCl, KOH, and KCl were measured in aqueous solutions of 2-butoxyethanol (BE) at 25 °C. The quantity, Λj′ = σ/xj, which is almost proportional to the molar conductivity, was extrapolated to the infinite dilution xj → 0. σ is the conductivity and xj is the mole fraction of j(= HCl, KOH, or KCl). The plots of 0Λj′, the value of Λj′ extrapolated to infinite dilution, against xBE showed a change in slope at xBE = 0.0175. The previous work from this laboratory indicated that the mixing scheme changes qualitatively at the same locus, xBE = 0.0175. By mixing scheme we simply mean the way in which BE and H2O molecules mix with each other. Assuming additivity in 0Λj′ in terms of constituent ions, those values for H+OH− were calculated. Plots of [Formula: see text] thus calculated as a function of xBE in the water-rich region, 0 < xBE < 0.0175, suggest that the hydrogen bond probability decreases in the bulk of solution, as xBE increases. Keywords: aqueous 2-butoxyethanol, ionic conductivities, mixing schemes, hydrogen bond network.


2018 ◽  
Vol 9 (30) ◽  
pp. 6361-6367 ◽  
Author(s):  
Manabu Hatano ◽  
Haruka Okamoto ◽  
Taro Kawakami ◽  
Kohei Toh ◽  
Hidefumi Nakatsuji ◽  
...  

Chiral C2- and C1-symmetric BINOL-derived bis(phosphoric acid) catalysts facilitated the enantioselective aza-Friedel–Crafts reaction of 2-methoxyfuran with α-ketimino esters.


Author(s):  
Austėja Mikalčiūtė ◽  
Linas Vilciauskas

Phosphoric acid and its mixtures with water are some of the best proton conducting materials known to science. Although, the proton conductivity in pure phosphoric acid decreases upon external doping...


2021 ◽  
pp. 120431
Author(s):  
Akinori Honda ◽  
Shunta Kakihara ◽  
Shuhei Ichimura ◽  
Kazuaki Tomono ◽  
Mina Matsushita ◽  
...  

2021 ◽  
Author(s):  
Xiang-Yang Liu ◽  
Teng-Shuo Zhang ◽  
Qiu Fang ◽  
Wei-Hai Fang ◽  
Leticia González ◽  
...  

2004 ◽  
Vol 60 (1) ◽  
pp. 90-96 ◽  
Author(s):  
Biserka Kojić-Prodić ◽  
Berislav Perić ◽  
Zoran Štefanić ◽  
Anton Meden ◽  
Janja Makarević ◽  
...  

To compare the structural properties of oxalamide and thiooxalamide groups in the formation of hydrogen bonds suitable for supramolecular assemblies a series of retropeptides was studied. Some of them, having oxalamide bridges, are gelators of organic solvents and water. However, retropeptides with oxygen replaced by the sp 2 sulfur have not exhibited such properties. The crystal structures of the two title compounds are homostructural, i.e. they have similar packing arrangements. The monothio compound crystallizes in the orthorhombic space group P212121 with two molecules in the asymmetric unit arranged in a hydrogen-bond network with an approximate 41 axis along the crystallographic b axis. However, the dithio and dioxo analogues crystallize in the tetragonal space group P41 with similar packing patterns and hydrogen-bonding systems arranged in agreement with a crystallographic 41 axis. Thus, these two analogues are isostructural having closely related hydrogen-bonding patterns in spite of the different size and polarity of oxygen and sulfur which serve as the proton acceptors.


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