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

摘要

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