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Free keywords:
Zwitterion; Phosphotungstate; Epoxidation; Surfactant; Emulsion
Abstract:
The combination of a certain zwitterion and sodium phosphotungstate provided an excellent catalyst for the epoxidation of cyclooctene: high TON was available even without any solvents and under ice bath condition. Based on characterizations by 1H, 13C and 31P NMR as well as FT-IR, Raman and UV–vis methods and investigations on the catalytic performance of the binary system, strong cooperative effect between zwitterions and sodium phosphotungstate was demonstrated. Here, the formation of stable W/O emulsion by the amphiphilic zwitterions seems to be crucial, which allows cyclooctene being in sufficient contact with the active phosphotungstate anions in the water phase.