Effect of CsF-concentration on electrolytic conductivity, viscosity and anodic reaction of nickel electrode in (CH3)3N-CsF-HF system at room temperature

摘要

In order to increase the formation ratio of perfluorotrimethylamine, (CF_3)_3N, to overall anode gas in electrolytic production using Ni anode, mixed melts of (CH_3)_3N·mHF + CsF·2.3HF were used as electrolytes at room temperature. The ionic conductivity of the mixed melts decreased with an increase in the CsF concentration, whereas the viscosity of the mixed melts increased with increasing the CsF concentration. AC impedance and XRD analysis revealed that the presence of CsNi_2F_6 in the oxidized layer formed on the Ni anode after electrolysis. The gas evolved at the Ni anode was composed of (CF_3)_3N, (CF_3)_2CHF_2N, CF_3(CHF_2)_2N, (CHF_2)_3N, CF_4, NF_3, CHF_3, C_2HF_5, and C_2F_6. The best ratio of (CF_3)_3N to the overall anode gas (52.11%) was obtained in the electrolyte of (CH_3)_3N·5.0HF + 50wt% CsF·2.3HF mixed melt at 20 mA cm~(-2).