吡啶类离子液体在类紫罗兰二烯烯丙位氧化中均相与非均相行为

The combination of relatively low-cost ionic liquids, simple copper salt, and terminal oxidant tert-butyl hydroperoxide provided an efficient and environmentally friendly approach to the preparation of ionone-like dienones. Six pyridinium ionic liquids were evaluated in allylic oxidation of α-ionone and β-ionone. The 60%–70% yields of 3-oxo-α-ionone were obtained with 0.02-0.20 mmol of CuCl2•2H2O as catalyst, 3-5 mmol of tert-butyl hydroperoxide as oxidant and 1 g of Bpy]PF6 as solvent for 4-20 h at 60°C. The facile recovery and recycle of catalyst were also achieved. More significantly, peculiar phase behaviors of Bpy]PF6 and Epy]PF6 offered the catalytic system advantages of homogeneous reaction and heterogeneous separation. Scanning electron microscope (SEM) images of Bpy]PF6 provided evidences for the behaviors. Transmission electron microscope (TEM) micrographs showed copper salt nanoparticles catalyst formed and stabilized in pyridinium ionic liquids.

Homogeneous and Heterogeneous Performances of Pyridinium Ionic Liquids in the Allylic Oxidation of Ionone-like Dienes

The combination of relatively low-cost ionic liquids, simple copper salt, and terminal oxidant tert-butyl hydroperoxide provided an efficient and environmentally friendly approach to the preparation of ionone-like dienones. Six pyridinium ionic liquids were evaluated in allylic oxidation of α-ionone and β-ionone. The 60%-70% yields of 3-oxo-α-ionone were obtained with 0.02-0.20 mmol of CuCl_2·2H_2O as catalyst, 3-5 mmol of tert-butyl hydroperoxide as oxidant and 1 g of Bpy]PF_6 as solvent for 4-20 h at 60℃. The facile recovery and recycle of catalyst were also achieved. More significantly, peculiar phase behaviors of Bpy]PF_6 and Epy]PF_6 offered the catalytic system advantages of homogeneous reaction and heterogeneous separation. Scanning electron microscope(SEM) images of Bpy]PF_6 provided evidences for the behaviors. Transmission electron microscope (TEM) micrographs showed copper salt nanoparticles catalyst formed and stabilized in pyridinium ionic liquids.