Peroxomolybdate Ions Bound to Latexes as Epoxidation Catalysts

摘要

Epoxidation of cyclooctene in aqueous hydrogen peroxide was catalyzed by ammoniummolybdate in the absence of organic solvent. Typically 1.3 mol % of Mo(VI) bound to 60 nm colloidal anion exchange polymers catalyzed 90% conversion of cyclooctene to 99% cyclooctene oxide by excess hydrogen peroxide in 24 h at 40 C. Only 12% epoxide was formed in the absence of colloidal particles. Under the same conditions styrene and cyclohexene gave complex product mixtures, and 1-octene did not react. The colloidal polymer supports enable oxidations of water-insoluble alkenes without use of organic solvents. Qualitatively the higher activity of the peraxo-molybdate bound to latex than in aqueous solution may be attributed to the higher local concentrations of both the alkene and the catalyst in the latex.