| 摘要 |
Boron compounds, e.g. BCl3, are removed from silicon halides or halogenosilanes, e.g. SiCl4 or HSiCl3, by contacting liquid or gaseous silicon halides or halogenosilanes or solutions thereof in an inert organic liquid with an acid or mixture of acids which are not solvents for these halides or solutions thereof and contain at least one anthraquinone and/or at least one substitution product of an anthraquinone dissolved therein. Anthraquinones or their substitution products include carmine, carminic acid, tetrahydroxyanthraquinone, 1,11-dianthrimide, 4,41-1,11-dichloroanthrimide, and 4,41-1,11-dibromoanthrimide, particularly alizarin or quinalizarin, advantageously employed in amounts 0,01-10% wt. in the acids or acid mixture. Acids include, sulphuric, phosphoric and chlorosulphonic and are preferably as anhydrous as possible. A mixture of sulphuric acid and phosphoric acid preferably in equal parts by volume is preferred. Purification may be carried out, for example, by direct contact of the liquid silicon halide or a solution of the solid halide in chloroform or carbon tetrachloride with the acid or mixture of acids in a separating funnel at preferably below 20 DEG C. Gaseous halides or vapours of volatile halides may be contacted in countercurrent with the acid or mixture of acids preferably heated to above the boiling point of the halide to be treated in a column packed with filler bodies. Acid or acid mixtures may be purified and returned to the process. |
