Gas chromatographic determination of silicon fluoride-chlorides SiСlnF4-n (n = 0 ÷ 4) obtained by the reaction of silicon tetrafluoride with aluminum chloride (III)

It is for the first time that the method of gas chromatography was used for the determination of silicon fluoride-chlorides SiСl n F 4-n ( n = 0 ÷ 4) which are the initial, intermediate and final substances while producing silicon tetrachloride from silicon tetrachloride and aluminum chloride (III). The analysis of samples taken during this reaction was carried out using the "Tsvet - 800" gas chromatographer. The samples were injected into the instrument using a vacuum dosing system. To separate the components, a chromatographic column made of molybdenum glass with a length of 5 m and an internal diameter of 3 mm was used. It was filled with a Chromatone N-AW-HMDS (grain size 0.250-0.315 mm) with 15% methylsilicon elastoplastic E-301. The registration of silicon fluoride-chlorides was implemented using a thermal conductivity detector. The identification of SiF 4 and SiCl 4 in the mixture was conducted by comparing the times of holding the chromatographic peaks with the times of holding these individual substances. The times of holding not available for SiClF 3 , SiCl 2 F 2 , SiCl 3 F in the individual states were determined using the dependence of the logarithm of the corrected holding time on their molecular mass. The concentrations of silicon fluoride-chlorides were determined using the internal normalization method. The data were obtained on the changes in the concentrations of these substances during the synthesis of silicon tetrachloride. The confirmation of the correctness of the analysis results was made using the method of varying the size of the sample. Key words:  silicon fluoride-chlorides, gas chromatography, identification, calibration factor, correctness (Russian)  DOI: http://dx.doi.org/10.15826/analitika.2019.23.4.011 Т .G. Sorochkina, О .Yu. Chernova, О .Yu. Troshin, А .Yu. Sozin, А .D. Bulanov, А . А . Ermakov G.G. Devyatykh Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences, ul. Tropinina 49, Nizhny Novgorod, 603950, Russian Federation