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Subject: search.filters.subject.540Institute: search.filters.UBSInstitut.Institut für Technische Thermodynamik und Thermische VerfahrenstechnikAuthor: search.filters.author.Kraus, Hamzeh

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    ItemOpen Access
    Confined Ru‐catalysts in a two‐phase heptane/ionic liquid solution : modeling aspects
    (2020) Kobayashi, Takeshi; Kraus, Hamzeh; Hansen, Niels; Fyta, Maria
    A modeling approach for atomic‐resolution studies of sup‐ ported ionic liquid phase (SILP) catalytic systems in silica mesoporous confinement with surface hydroxyl and functional groups is proposed. First, a force field for the Ru‐based catalyst is developed. Second, its solvation behavior within a bulk two‐phase system of heptane and an IL is studied. Third, static and dynamic properties of the confined system are investigated. Using classical molecular dynamics simulations, experimentally inaccessible properties can thus be studied that are important for an optimization of a SILP system for performing a ring‐closing metathesis reaction.
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    ItemOpen Access
    Influence of ionic liquid film thickness and flow rate on macrocyclization efficiency and selectivity in supported ionic liquid‐liquid phase catalysis
    (2024) Högler, Marc; Kobayashi, Takeshi; Kraus, Hamzeh; Atwi, Boshra; Buchmeiser, Michael R.; Fyta, Maria; Hansen, Niels
    Supported ionic‐liquid phase (SILP) technology in a biphasic setting with n ‐heptane as the transport phase was applied to the Ru‐alkylidene‐N‐heterocyclic carbene (NHC) catalyzed macrocyclization of α , ω ‐dienes to elucidate the effect of ionic liquid (IL)‐film thickness, flow rate as well as substrate and product concentration on macrocyclization efficiency, and Z ‐selectivity. To understand the molecular‐level behavior of the substrates and products at the n ‐heptane/IL interphase, atomistic molecular dynamics simulations were conducted and correlated with experimental observations. The thickness of the IL layer strongly influences the Z/E ratio of the products in that a thin IL layer favors higher Z/E ratios by confining the catalyst between the pore wall and the liquid‐liquid interphase whereas a thick IL layer favors formation of the E ‐product and Ru‐hydride catalyzed isomerization reactions. Also, macrocyclization efficiency, expressed by the ratio of oligomers/macromonocycle (O/MMC), is influenced both by the flow rate and the thickness of the IL layer.