Electrolysis of mixed melt of (CH 3) 4NF· mHF+ x wt.% CsF·2.0HF with nickel anode

Abstract

A new process for electrolytic synthesis of a perfluorinated compound using mixed melts of (CH 3) 4NF·4.0HF+ x wt.% CsF·2.0HF as electrolytes and Ni sheet anode at room temperature was developed. The addition of CsF·2.0HF reduced the overvoltage of the Ni anode. The surface film on the anode formed in the presence of CsF·2.0HF consisted of inorganic compounds of NiF 2, CsNi 2F 6, and an organic compound of (CH 3) 4NF. The presence of CsNi 2F 6, which is a highly oxidized nickel compound, gave a high electronic conductivity to the film and decreased the anode overvoltage. The gas evolved on the anode was composed of (CF 3) 3N and CF 4 as main products with small amounts of NF 3, C 2F 6, CHF 3, C 2HF 5, CF 3N(CF 2H) 2, and (CF 3) 2NCHF 2. The addition of 20 wt.% CsF·2.0HF gave the highest ratio of (CF 3) 3N of 40.5% when the electrolysis was carried out at 5 mA cm −2 at room temperature.