Separation Process of Boron Compounds in Chlorosilanes and Composition for Evaporating Chlorosilanes

摘要

PURPOSE: To remove or concentrate a minute amount of boron compounds in chlorosilanes with simple operation by allowing a fluorine-element-containing salt to act on the chlorosilanes containing boron compounds to adsorb the boron compounds on the salt. CONSTITUTION: This separation process comprises: adding a fluorine-element- containing salt to chlorosilanes; mildly agitating the resulting mixture at ordinary temperature; and thereafter, slowly evaporating the chlorosilanes to remove boron compounds in the chlorosilanes. Alternatively, the process comprises: packing a cylindrical vessel with a fluorine-element containing salt used as an adsorbent; and passing chlorosilanes through the vessel to adsorb boron compounds in the chlorosilanes on the salt. As the fluorine-element-containing salt, an electrolyte or more specifically, NaF, KF, CaF2, MgF2, NH4F, BaF2, triphenyltin fluoride, tributyltin fluoride, or the like, can be used. Such a fluorine-element-containing salt is added to chlorosilanes in an amount sufficient to provide a stoichiometrical molar ratio of 1:1 of the amount of the salt to the boron compound content in the chlorosilanes.