Synthesis and high-throughput testing of multilayered supported ionic liquid catalysts for the conversion of CO2 and epoxides into cyclic carbonates

Multilayered covalently supported ionic liquid phase (mlc-SILP) materials were synthesised by grafting
different bis-vinylimidazolium salts on thiol-functionalised silica. These materials, which contain a crosslinked
oligomeric network of imidazolium units, were characterised and tested as catalysts for the reaction
of carbon dioxide with various epoxides to produce cyclic carbonates. The materials prepared by
supporting a bis-imidazolium iodide salt with xylene or octane as a linker between the imidazolium
units were identified as the most active catalysts and displayed high turnover numbers and improved
productivity compared to known supported ionic liquid catalysts. The most promising mlc-SILP catalysts
were further studied to tune the reaction conditions towards optimum catalytic performance and to
investigate their versatility with different substrates and their reusability. The rapid and parallel screening
of the catalysts was efficiently carried out by means of high-throughput (HT) experimentation.