Kemp Elimination: A Probe Reaction To Study Ionic Liquids Properties

Abstract

The amino induced elimination of benzisoxazole into the relevant o-cyanophenolate ion (Kemp elimination) has been studied in [bmim][BF 4] solution at 298 K. To have information about the interactions between reactants and ionic liquid, the reaction has been carried out at different temperatures (293-313 K). Several primary, secondary, and tertiary amines have been used to study the effect of amine structure on the reaction rate. The collected data show that the amine structure seems to have a crucial role in determining the reaction rate. Furthermore, as different cation or anion structures of an ionic liquid can significantly affect its properties, the title reaction has been performed in four different ionic liquids ([bmim][PF6], [bmim][NTf 2], [bm 2im][NTf 2], and [bmpyrr][NTf 2]), using pyrrolidine and piperidine as model amines. An H-donor negative solvent (MeOH and [bmim][NTf 2]) effect on reaction rate was detected. Finally, a narrow range of activation parameters was calculated both for the reaction induced by different amines and for pyrrolidine and piperidine, in the presence of different ILs. This fact suggests the occurrence of an "early" transition state.

The Effect of the Cation π‐Surface Area on the 3D Organization and Catalytic Ability of Imidazolium‐Based Ionic Liquids

“…These could play an important role in determining the 3D structure of the solvent media. Consequently, the variation of the signal multiplicity with temperature can be ascribed to changes in the structural organization and in the 3D network of the ILs 11d…”

Quantum and molecular mechanical Monte Carlo techniques for modeling condensed‐phase reactions

“…Computed changes in free energy yielded a Δ G ‡ value of 25.2 ± 1 kcal/mol. The experimental Δ G ‡ for the reaction under the same conditions is 22.6 ± 0.5 kcal/mol . The same PDDG/PM3‐based QM/MM methodology was also successfully applied to examine the catalysis of the Kemp elimination of 5‐nitro‐benzisoxazole by catalytic antibody 34E4 and its Glu50Asp variant .…”

Thermodynamic, structural and dynamic properties of ionic liquids [C4mim][CF3COO], [C4mim][Br] in the condensed phase, using molecular simulations

“…Also, in this work, dynamic properties for the [ ] ILs were calculated, since these ILs have been studied extensively, particularly, these ILs have been tested as reaction media in condensed phase. 28,[38][39][40] The developed FF for these ILs has been published in previous works. 24,41 Tables 1 and 2 present both the experimental and simulated physicochemical properties available in the literature for the six ILs studied; and to the best of our knowledge, there is scarce reported data for the [ The shear viscosity (h) the self-diffusion coefficient (D i ) and the thermal conductivity (l) are called transport properties, and various Molecular Dynamics simulations reported in the literature tend either to underestimate or overestimate the experimental data.…”