Octadecyl

Although catalyst IV also has good catalytic performance, it was totally soluble in the reaction system during and after the epoxidation, because it contains a big octadecyl benzyl dimethyl ammonium ion.

A 0.5-ml sample of the supernatant was put on a 6-ml activated, octadecyl solid-phase extraction cartridge (Bakerbond, J. T. Baker, Phillipsburg, NJ) and eluted with 2-ml volumes of H 2 O, 50% CH 3 CN (Low-UV HPLC grade, Burdick and Jackson) in H 2 O, and CH 3 CN. All fractions were concentrated to near dryness under vacuum (Speed Vac rotary concentrator, Savant Instruments, Farmingdale, NY) and redissolved in 0.5 ml of 50 mM pH 8 buffer, for bioassay.