Kinetic Model of Two‐Phase Epoxidation with Ionic Liquids as Micellar Catalysts

Abstract

The biphasic catalytic epoxidation of cyclooctene using the ionic liquid (IL) 1,2‐dimethyl‐3‐octyl‐imidazolium perrhenate ([OMMIM]ReO4) as micellar catalyst and H2O2 as oxidant was investigated. Kinetic experiments were carried out in the intrinsic kinetic regime as proved by variation of stirring rate and temperature. Variation of catalyst concentration allowed for determination of the critical micellar concentration (CMC) of the catalytic IL. The effect of substrate concentrations on the reaction rate was also assessed. Based on the experiments, a kinetic model adapted from enzyme catalysis was proposed to account for the micellar reaction environment. The model takes into account the onset of micelle formation at the CMC. The application of the kinetic model illustrated the good agreement with the experimental data. The model will be applied to other micellar epoxidation reactions and for the design of an appropriate reaction setup in the future.

Epoxidation of unsaturated fatty acid ester promoted by imidazolium acidic ionic liquids: An unexpected selectivity phenomena

“…Its presence may influence the course of the epoxidation reaction, especially the selectivity, due to the presence of acid protons, which can attack the oxirane ring causing its partial opening to the corresponding diol (Figure 3b). This effect was not observed when the epoxidation reaction was carried out in the presence of neutral ionic liquids [31–33] . The effect of strongly acidic protons was observed by examining the behavior of epoxidized fatty acid esters in the presence of an aqueous solution containing the system [Rmim]HSO 4 /H 2 SO 4 [15] …”

“…This effect was not observed when the epoxidation reaction was carried out in the presence of neutral ionic liquids. [31][32][33] The effect of strongly acidic protons was observed by examining the behavior of epoxidized fatty acid esters in the presence of an aqueous solution containing the system [Rmim]HSO 4 /H 2 SO 4 . [15] Theoretically, in functionalized hydrogen sulfate imidazolium ionic liquids, four structural centers can be indicated related to the possible impact on the catalytic process: the weakly "acidic" proton C2-H 1; alkyl chain 2; OH functional group 3 and the strongly acidic HSO 4 anion of the ionic liquid 4 (Figure 4).…”

Kinetics of Epoxidation of Cyclooctene with Ionic Liquids Containing Tungstate as Micellar Catalyst

“…In a previous paper, an approach to determine the kinetics of a 1-octyl-3-methylimidazolium perrhenate [OMIM][ReO 4 ]catalyzed micellar catalysis was presented [13,14]. Therein, the micellar catalyst system was prepared by simply dissolving the Bastian Zehner As the tungstate anion is known as active species in the catalysis of epoxidation reactions, a tungstate IL micellar catalyst was prepared using the same protocol [15,16].…”