ELECTROCHEMICAL BEHAVIOR OF OXYGEN / SUPEROXIDE ION COUPLE IN 1-BUTYL-1-METHYLPYRROLIDINIUM BIS(TRIFLUOROMETHANESULFONE)IMIDE ROOM-TEMPERATURE MOLTEN SALT

摘要

The electrochemical behavior of oxygen (O_2) / superoxide ion (O_2~-) couple was investigated with the aid of ultra micro electrode technique in 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfone)imide room-temperature molten salt. The diffusion coefficient of O_2 was (1.8 + - 0.2) × 10~(-6) cm~2 s~(-1) at 25 deg C. The activation energy of the diffusion process of O_2 was estimated to be 27 kJ mol~(-1) from the temperature dependence of the diffusion coefficient. The solubility of O_2 in BMPTFSI was 14 mmol dm~(-3) at 25 deg C and decreased with an increase in temperature. The diffusion coefficient of O_2~- was 0.86 × 10~(-6) cm~2 s~(-1) at 25 deg C. The formal potential of O_2 / O_2 - couple was 1.13 V vs. ferrocene / ferrocenium.