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Mechanism of the Water–Gas Shift Reaction Catalyzed by Efficient Ruthenium‐Based Catalysts: A Computational and Experimental Study
Author(s) -
Stepić Robert,
Wick Christian R.,
Strobel Vinzent,
Berger Daniel,
VučemilovićAlagić Nataša,
Haumann Marco,
Wasserscheid Peter,
Smith AnaSunčana,
Smith David M.
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201811627
Subject(s) - catalysis , water gas shift reaction , chemistry , ionic liquid , ruthenium , hydroxide , reaction mechanism , nucleophile , chloride , hydrogen chloride , inorganic chemistry , hydrogen , organic chemistry
Supported ionic liquid phase (SILP) catalysis enables a highly efficient, Ru‐based, homogeneously catalyzed water‐gas shift reaction (WGSR) between 100 °C and 150 °C. The active Ru‐complexes have been found to exist in imidazolium chloride melts under operating conditions in a dynamic equilibrium, which is dominated by the [Ru(CO) 3 Cl 3 ] − complex. Herein we present state‐of‐the‐art theoretical calculations to elucidate the reaction mechanism in more detail. We show that the mechanism includes the intermediate formation and degradation of hydrogen chloride, which effectively reduces the high barrier for the formation of the requisite dihydrogen complex. The hypothesis that the rate‐limiting step involves water is supported by using D 2 O in continuous catalytic WGSR experiments. The resulting mechanism constitutes a highly competitive alternative to earlier reported generic routes involving nucleophilic addition of hydroxide in the gas phase and in solution.