h1

% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@PHDTHESIS{Ohligschlger:811781,
      author       = {Ohligschläger, Andreas},
      othercontributors = {Liauw, Marcel and Herres-Pawlis, Sonja},
      title        = {{E}rmittlung kinetischer {D}etails der {C}1- und
                      {C}2-{C}hemie mit in-situ-{S}pektroskopie},
      school       = {RWTH Aachen University},
      type         = {Dissertation},
      address      = {Aachen},
      publisher    = {RWTH Aachen University},
      reportid     = {RWTH-2021-01423},
      pages        = {1 Online-Ressource (19, 178 Seiten) : Illustrationen,
                      Diagramme},
      year         = {2021},
      note         = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
                      University 2021; Dissertation, RWTH Aachen University, 2021},
      abstract     = {Chemical transformations of C1- and C2-substances are often
                      performed in highly concentrated solutions or neat
                      conditions to simplify the purification of the product.
                      Substrates and products may behave as very different
                      solvents so that e.g. the polarity of the reaction mixture
                      changes with ongoing reaction. This influences the reaction
                      kinetics, since the solvation enthalpies of substrates and
                      transition states change at the same moment. Thus, the
                      apparent rate coefficient depends on conversion and time.
                      This makes time-resolved measurement of the concentrations
                      necessary to accomplish accurate reaction kinetics.
                      In-situ-IR- and in-situ-Raman-spectroscopy are used for this
                      task. Three reaction systems of C1- and C2-chemistry are
                      investigated that are based on methanol and exhibit a
                      distinct feature: 1. The ionic liquid synthesis of dimethyl
                      carbonate and nucleophilic nitrogen-bases is affected by a
                      strong increase of solvent polarity, since two neutral
                      molecules form an ionic product. The apparent rate
                      coefficient increases with ongoing reaction and follows the
                      model of a kinetic salt effect. The progress of the apparent
                      rate coefficient shows bends that can be assigned to
                      spontaneous changes in the solvent environment. 2. The
                      esterification of acetic acid and ethanol is investigated in
                      a biphasic liquid/liquid reactor. The produced ester is
                      extracted to the unipolar phase. The partition coefficients,
                      mass transfer coefficients and reaction kinetics are
                      determined in a single reactor. The combination of the
                      latter two results shows that the reaction proceeds under
                      kinetic limitation. 3. The Guerbet reaction from ethanol to
                      n-butanol can be described by a network with de-sired and
                      undesired single-steps. The reaction network is divided into
                      redox-catalyzed and base-dependent subsystems whose kinetics
                      are determined in separated experiments. A model of the
                      whole reaction network is assembled and reactions are
                      simulated with varied starting parameters. The plot
                      n-butanol yield versus temperature and hydrogen pressure
                      follows a saddle as either the first reaction step is
                      suppressed (high pressure) or the side-reactions are
                      accelerated disproportionately high (high temperature).
                      Lastly, a high activation barrier of the dehydrogenation of
                      acetaldehyde/1-ethoxyethanol can be identified as a good
                      feature of a Guerbet redox-catalyst.},
      cin          = {154110 / 150000},
      ddc          = {540},
      cid          = {$I:(DE-82)154110_20140620$ / $I:(DE-82)150000_20140620$},
      typ          = {PUB:(DE-HGF)11},
      doi          = {10.18154/RWTH-2021-01423},
      url          = {https://publications.rwth-aachen.de/record/811781},
}