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

The kinetics of cyclooctene epoxidation with H2O2 by micellar catalysis was studied. As catalyst, an ionic liquid (IL) containing the catalytically active tungstate anion was used. The tungstate IL forms micelles in the aqueous H2O2 phase. It is simply formed by dissolving sodium tungstate and 1-octyl-3-methylimidazolium tetrafluoroborate [OMIM][BF4] in aqueous H2O2. For the epoxidation of cyclooctene by micellar catalysis, a power law kinetic model was determined that takes the critical micelle concentration into account. The kinetics of the [OMIM][BF4]/Na2WO4 catalyst is similar to pure [OMIM](2)[WO4], which indicates that the active species is formed in situ. Addition of phenylphosphonic acid improves the activity of the tungstate IL. The most effective catalyst was tested in a semi-continuous and continuous loop reactor.