In order to increase the formation ratio of perfluorotrimethylamine, (CF3)(3)N, to overall anode gas in electrolytic production using Ni anode, mixed melts of (CH3)(3)N center dot mHF+ CsF center dot 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 CsNi2F6 in the oxidized layer formed on the Ni anode after electrolysis. The gas evolved at the Ni anode was composed of (CF3)(3)N, (CF3)(2)CHF2N, CF3(CHF2)(2)N, (CHF2)(3)N, CF4, NF3, CHF3, C-2, and C2F6. The best ratio of (CF3)(3)N to the overall anode gas (52.11%) was obtained in the electrolyte of (CH3)(3)N center dot 5.0HF + 50 wt% CsF.2.3HF mixed melt at 20 mA cm(-2). (C) 2011 Elsevier Ltd. All rights reserved.