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Author: Peppel, Tim × Author: Wohlrab, Sebastian × End date: 2019 × Start date: 2010 × Type: Text × WGL Institute: LIKAT ×

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Now showing 1 - 6 of 6
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    Crystal structure of (E)-dodec-2-enoic acid
    (Chester : International Union of Crystallography, 2015) Sonneck, Marcel; Peppel, Tim; Spannenberg, Anke; Wohlrab, Sebastian
    The crystal structure of (E)-dodec-2-enoic acid, C12H22O2, an [alpha],[beta]-unsaturated carb­oxy­lic acid with a melting point (295 K) near room temperature, is characterized by carb­oxy­lic acid inversion dimers linked by pairs of O-H...O hydrogen bonds. The carb­oxy­lic acid group and the following three carbon atoms of the chain of the (E)-dodec-2-enoic acid mol­ecule lie almost in one plane (r.m.s. deviation for the four C atoms and two O atoms = 0.012 Å), whereas the remaining carbon atoms of the hydro­carbon chain adopt a nearly fully staggered conformation [moduli of torsion angles vary from 174.01 (13) to 179.97 (13)°].
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    Crystal structure of (E)-undec-2-enoic acid
    (Chester : International Union of Crystallography, 2015) Sonneck, Marcel; Peppel, Tim; Spannenberg, Anke; Wohlrab, Sebastian
    In the mol­ecule of the title low-melting [alpha],[beta]-unsaturated carb­oxy­lic acid, C11H20O2, the least-squares mean line through the octyl chain forms an angle of 60.10 (13)° with the normal to plane of the acrylic acid fragment (r.m.s. deviation = 0.008 Å). In the crystal, centrosymmetrically related mol­ecules are linked by pairs of O-H...O hydrogen bonds into dimers, forming layers parallel to the (041) plane.
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    Crystal structure of (E)-hex-2-enoic acid
    (Chester : International Union of Crystallography, 2015) Peppel, Tim; Sonneck, Marcel; Spannenberg, Anke; Wohlrab, Sebastian
    The crystal structure of the title compound, C6H10O2, an [alpha],[beta]-unsaturated carb­oxy­lic acid, displays carb­oxy­lic acid inversion dimers linked by pairs of O-H...O hydrogen bonds. The packing is characterized by layers of acid dimers. All the non-H atoms of the (E)-hex-2-enoic acid mol­ecule lie almost in the same plane (r.m.s. deviation for the non-H atoms = 0.018 Å).
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    Crystal structure of (E)-pent-2-enoic acid
    (Chester : International Union of Crystallography, 2015) Peppel, Tim; Sonneck, Marcel; Spannenberg, Anke; Wohlrab, Sebastian
    The mol­ecule of the title compound, C5H8O2, a low-melting [alpha],[beta]-unsaturated carb­oxy­lic acid, is essentially planar [maximum displacement = 0.0239 (13) Å]. In the crystal, mol­ecules are linked into centrosymmetric dimers via pairs of O-H...O hydrogen bonds.
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    Synthesis and molecular structures of the lowest melting odd- and even-numbered a,b-unsaturated carboxylic acids—(E)-hept-2-enoic acid and (E)-oct-2-enoic acid
    (Basel : MDPI, 2016) Sonneck, Marcel; Spannenberg, Anke; Wohlrab, Sebastian; Peppel, Tim
    The molecular structures of the two lowest melting odd- and even-numbered α,β-unsaturated carboxylic acids—(E)-hept-2-enoic acid (C7) and (E)-oct-2-enoic acid (C8)—are herein reported. The title compounds were crystallized by slow evaporation of ethanolic solutions at −30 °C. C7 crystallizes in the triclinic space group P1¯ with two molecules in the unit cell and C8 in the monoclinic space group C2/c with eight molecules in the unit cell. The unit cell parameters for C7 are: a = 5.3049(2) Å, b = 6.6322(3) Å, c = 11.1428(5) Å, α = 103.972(3)°, β = 97.542(3)°, γ = 90.104(3)°, and V = 376.92(3) Å3 (T = 150(2) K). The unit cell parameters for C8 are: a = 19.032(10) Å, b = 9.368(5) Å, c = 11.520(6) Å, β = 123.033(11)°, and V = 1721.80(16) Å3 (T = 200(2) K).
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    Combination of chemo- and biocatalysis: Conversion of biomethane to methanol and formic acid
    (Basel : MDPI, 2019) Kunkel, Benny; Seeburg, Dominik; Peppel, Tim; Stier, Matthias; Wohlrab, Sebastian
    In the present day, methanol is mainly produced from methane via reforming processes, but research focuses on alternative production routes. Herein, we present a chemo-/biocatalytic oxidation cascade as a novel process to currently available methods. Starting from synthetic biogas, in the first step methane was oxidized to formaldehyde over a mesoporous VOx/SBA-15 catalyst. In the second step, the produced formaldehyde was disproportionated enzymatically towards methanol and formic acid in equimolar ratio by formaldehyde dismutase (FDM) obtained from Pseudomonas putida. Two processing routes were demonstrated: (a) batch wise operation using free formaldehyde dismutase after accumulating formaldehyde from the first step and (b) continuous operation with immobilized enzymes. Remarkably, the chemo-/biocatalytic oxidation cascades generate methanol in much higher productivity compared to methane monooxygenase (MMO) which, however, directly converts methane. Moreover, production steps for the generation of formic acid were reduced from four to two stages. © 2019 by the authors.