Synthesis And Physical Properties Of Si_xF_y

In China,most of fluorine and silicon chemical products are low-end and generic products,its profit margins are low,and the high-end products rely on imports,product structural contradiction,excess low-end products,high-end products are shortage.Compared with foreign countries,independent innovation capability of fluorine silicon industry is weak,a single research and development direction,applied technology and processing equipment are behind,less downstream applied research,insufficient research and development lead to integrated low competitiveness,which is the biggest problem of the development of fluorine silicon industry at present.With the development of high-tech and high-end silicon industry,fluorine silicon will have a broad market space and good prospects for development.Therefore,it is meaningful and necessary to optimize synthetic route and develop effective analytical protocols for perfluorosilicon compounds(Si_xF_y).Silicon tetrafluoride(SiF₄)is widely used as a raw material in the synthesis of perfluorosilicon and other fluorine silane.Therefore,in this paper,silicon tetrafluoride was synthesized by decomposing fluosilicic acid in concentrated heated sulfuric acid.Impurities were removed.Silicon difluoride(SiF₂)was prepared from silicon tetrafluoride and silicon as raw materials.Synthetic protocol was optimized and stability of the product was also studied.These include:analysis of silicon fluoride by IR and MS,and comparation with references to determine synthetic products,and with the relevant references are compared to determine the product for the synthesis of the target product.Experimental parameters such as reaction temperature,addition rate of fluorosilicic acid were investigated to obtain optimized synthetic conditions for silicon difluoride.Perfluorosilicon compounds was analysed by IR and MS.Stability of silicon tetrafluoride,silicon difluoride,and a series of perfluorosilicon were studied at both room temperature and high temperature.Conclusions are:(1)Silicon tetrafluororide is stable at both room temepreature and high temperature;(2)Silicon difluoride and perfluorosilicon will decompose in a short period of time at room temperature;(3)Silicon difluoride is stable after heating for 1 hour in high temperature,while perfluorosiilcon is unstable and will decomposed into silicon and silicon tetrafluoride.