Efficient and selective oxidation of sulfides in batch and continuous flow using styrene-based polymer immobilised ionic liquid phase supported peroxotungstates

Academic Article

Abstract

  • © 2016 The Royal Society of Chemistry. Styrene-based peroxotungstate-modified polymer immobilized ionic liquid phase catalysts [PO 4 {WO(O 2 ) 2 } 4 ]@ImPIILP (Im = imidazolium) are remarkably efficient systems for the selective oxidation of sulfides under mild conditions both in batch and as a segmented or continuous flow process using ethanol as the solvent and mobile phase, respectively. The performance of these styrene-based systems has been compared against their ring opening metathesis polymerisation derived counterparts to assess their relative merits. A comparative survey revealed the catalyst supported on N-benzyl imidazolium decorated polymer immobilised ionic liquid to be the most efficient and a cartridge packed with a mixture of [PO 4 {WO(O 2 ) 2 } 4 ]@ImPIILP and silica operated as a segmented or continuous flow system giving good conversions and high selectivity for sulfoxide. The immobilised catalyst remained highly active for the sulfoxidation of thioanisole in ethanol with a stable conversion-selectivity profile for up to 8 h under continuous flow operation; for comparison conversions with a mixture of [NBu 4 ] 3 [PO 4 {WO(O 2 ) 2 } 4 ] and silica dropped dramatically after only 15 min as a result of rapid leaching while [PO 4 {WO(O 2 ) 2 } 4 ]@ImPIILP prepared from commercially available Merrifield resin also gave consistently lower conversions; these benchmark comparisons serve to underpin the potential benefits of preparing the polymer immobilized ionic liquid supports.
  • Authors

    Published In

  • RSC Advances  Journal
  • Digital Object Identifier (doi)

    Author List

  • Doherty S; Knight JG; Carroll MA; Clemmet AR; Ellison JR; Backhouse T; Holmes N; Thompson LA; Bourne RA
  • Start Page

  • 73118
  • End Page

  • 73131
  • Volume

  • 6
  • Issue

  • 77