A comparison of the oxidation of lignin model compounds in conventional and ionic liquid solvents and application to the oxidation of lignin

Abstract

The oxidation of lignin model compounds was studied in conventional solvents in parallel with oxidations in ionic liquid solvents. Catalyst systems were investigated in ionic liquid solvents to determine how reaction rates and the selectivity for benzylic carbon oxidation were affected. Oxidation rates were often lower in ionic liquids than in conventional solvents – as indicated by lower conversion in a standard reaction time – likely due, at least in part, to the higher viscosity of ionic liquids. Selectivity of the TPPFeCl/t-BuOOH catalyst system for oxidation of the benzylic C–OH versus benzylic C–H was higher in the ionic liquids tested than in conventional solvents.