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To understand the ionic and nonionic species in (CH(3))(4)NF·mHF, (CH(3))(3)N·mHF, (C(2)H(5))(4)NF·mHF, and (C(2)H(5))(3)N·mHF melts, the structures of these melts were investigated by infrared spectroscopy, NMR, and high-energy X-ray diffraction. Infrared spectra revealed that three kinds of fluorohydrogenate anions, (FH)(n)F(-) (n = 1, 2, and 3), and molecular hydrofluoric acid (HF) are present in every melt. Ionic conductivity and viscosity of these melts were measured and correlated with their cationic structure. The ionic conductivity of the R(4)N(+)-systems was higher than that of corresponding R(3)NH(+)-systems because a strong N-H···F(HF)(n) interaction prevents the motion of R(3)NH(+) cations in the R(3)N·mHF melts. (CH(3))(4)N(+) and (CH(3))(3)NH(+) cations gave higher ionic conductivity than (C(2)H(5))(4)N(+) and (C(2)H(5))(3)NH(+) cations, respectively, because the ionic radii of former cations were smaller than those of latter. It was concluded that these effects on ionic conductivity can be explained by the cationic structure and the concentration of molecular HF in the melts.

In order to improve the curent efficiency for perfluorotrimethylamine, (CF3)3N, formation using the Ni anode, the mixed melts of (CH3)3N·mHF+CsF·2.3HF were used as an electrolyte at a room temperature. The electrolytic conductivity of the mixed melt decreased with an increase in the CsF-concentration, whereas the viscosity of the mixed melt increased with increasing the CsF-concentration. XRD analysis revealed that CsNi2F6 was present in the oxidized layer formed on the Ni anode in the mixed melts. The gas evolved at the Ni anode in the mixed melt of (CH3)3N·5.0HF and CsF·2.3HF was composed of (CF3)3N, (CF3)2CHF2N, CF3(CHF2)2N, (CHF2)3N, CF4, NF3, CHF3, C2HF5, and C2F6. The best ratio of (CF3)3N to total anode gas was obtained in electrolysis of (CH3)3N·5.0HF + 50 wt.% CsF·2.3HF mixed melt at 20 mA cm−2 and its value was 52.11%.

Since a boron-doped diamond (BDD) electrode is able to be used as an anode in the (CH3)4NF•mHF melt, the performance of BDD anode for electrolytic production of perfluorotrimethylamine [(CF3)3N] was investigated in the melt of (CH3)4NF•5.0HF by galvanostatic electrolysis at 20, 40, 60 and 100 mA•cm−2. The anode gas was analyzed quantatively by gas chromatography-mass spectroscopy. Also, the surface of BDD electrode before and after electrolysis was analyzed by XRD and Raman spectroscopy and was observed by SEM. The ratios of (CF3)3N and (CF3)2CHF2N to overall anode gas increased with increasing the current density. This fact suggests that electrolytic fluorination may be promoted at higher current density. From the results of surface analyses, it is concluded that the electrolytic production of (CF3)3N from (CH3)4NF•5.0HF melt using a BDD anode is an appropriate process because the BDD film on the carbon substrate has a good electric conductivity during electrolysis.