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On the Mechanism of the Reactivity of 1,3‐Dialkylimidazolium Salts under Basic to Acidic Conditions: A Combined Kinetic and Computational Study
Author(s) -
Rico del Cerro Daniel,
MeraAdasme Raúl,
King Alistair W. T.,
PereaBuceta Jesus E.,
Heikkinen Sami,
Hase Tapio,
Sundholm Dage,
Wähälä Kristiina
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201805016
Subject(s) - chemistry , reactivity (psychology) , yield (engineering) , kinetic energy , carbene , ionic liquid , catalysis , activation energy , impurity , reaction mechanism , computational chemistry , inorganic chemistry , organic chemistry , thermodynamics , medicine , physics , alternative medicine , pathology , quantum mechanics
Comprehensive spectroscopic kinetic studies illustrate an alternative mechanism for the traditional free‐carbene intermediated H/D exchange reaction of 1,3‐dialkylimidazolium salts under neutral (D 2 O) and acidic conditions (DCl/D 2 O 35 wt % solution). The deuteration of high purity [bmim]Cl in D 2 O is studied at different temperatures, in absence of catalyst or impurities, to yield an activation energy. DFT transition‐state modelling, of a small water cluster and [bmim] cation, also yields an activation energy which strongly supports the proposed mechanism. The presence of basic impurities are shown to significantly enhance the exchange reaction, which brings into question the need for further analysis of technical purities of ionic liquids and the implications for a wide range of chemical reactions in such media.