Selective Oxidation of Aromatic Olefins Catalyzed by Copper(II) Complex in Micellar Media

The selective oxidation of aromatic olefins 1,2-dimethoxy-4-vinylbenzene (DEVB) and 2-methoxy-4-vinylphenol (MOVP) by H2O2 into 1-(3,4-dime-thoxyphenyl)ethanol (MVA) and 1-(4-hydroxy-3-methoxyphenyl)ethanol (HMOPE) catalyzed by copper(II) complex CuL (L = 6,8,15,17-tetramethyl-7,16-dihydrodibenzo-1,4,8,11-tetraazacyclotetradecine) were achieved in cationic surfactant cetyl trimethylammonium bromide (CTAB), anionic surfactant sodium dodecyl benzene sulfonate (SDBS) and nonionic surfactant Triton X-100 (TX-100) micellar media, respectively. Micelle showed great influence on both reaction rate and selectivity of product. Aromatic olefins could be oxidized into corresponding aromatic ketones in aqueous solution, but into secondary alcohols in micellar media. The combination of TEMPO and CuL/H2O2 resulted in relatively fast reaction rate and S > 96% selectivity of aromatic ketones. The reaction rate constants, k 1, k 2 and k 3 for three oxidation reactions pathways: olefin to ketone, olefin to alcohol and alcohol to ketone were obtained, respectively. The kinetic study indicated that the CuL catalyzed oxidation of olefins by H2O2 to alcohols was a relatively rapid and major reaction and ketone was generated by the direct oxidation of olefins, not by further oxidation of alcohol in micellar media.