In order to produce high-purity trichlorosilane by removing methyldichlorosilane from a mixture (S) containing methyldichlorosilane (CH.sub.3HSiCl.sub.2), tetrachlorosilane (SiCl.sub.4), and trichlorosilane (HSiCl.sub.3) in the method for producing trichlorosilane of the present invention, a procedure is employed in which chlorine atoms are redistributed between methyldichlorosilane and tetrachlorosilane through catalytic treatment for conversion into trichlorosilane and methyltrichlorosilane (CH.sub.3SiCl.sub.3). Methyldichlorosilane (boiling point: 41° C.) having a boiling point close to that of trichlorosilane (boiling point: 32° C.) to be purified is converted into methyltrichlorosilane (boiling point: 66° C.) having a higher boiling point through redistribution of chlorine atoms between methyldichlorosilane and tetrachlorosilane, achieving easy removal of impurities.

Trihalosilane refining device having a divided wall distillation column is disclosed. The trihalosilane refining device can be useful in obtaining high-purity trihalosilane from a feed containing a trihalosilane while consuming a small amount of energy.

The invention relates to a process and an apparatus for controlled preparation of octachlorotrisilane from monomeric chlorosilanes, by subjecting the chlorosilanes to a thermal plasma.

The invention relates to a process and an apparatus for controlled preparation of octachlorotrisilane from monomeric chlorosilanes, by subjecting the chlorosilanes to a thermal plasma.

When a disproportionated chlorosilane is to be produced by causing a starting material chlorosilane liquid to flow through a catalyst-packed layer which is packed with a weakly basic anion exchange resin as a disproportionation reaction catalyst to carry out a disproportionation reaction, before the disproportionation reaction is carried out, the disproportionation reaction catalyst is brought into contact with a processing gas obtained by diluting a chlorosilane with an inert gas to prevent the deterioration of the disproportionation reaction catalyst at the start of the reaction so as to carry out the disproportionation of the chlorosilane efficiently.

When a disproportionated chlorosilane is to be produced by causing a starting material chlorosilane liquid to flow through a catalyst-packed layer which is packed with a weakly basic anion exchange resin as a disproportionation reaction catalyst to carry out a disproportionation reaction, before the disproportionation reaction is carried out, the disproportionation reaction catalyst is brought into contact with a processing gas obtained by diluting a chlorosilane with an inert gas to prevent the deterioration of the disproportionation reaction catalyst at the start of the reaction so as to carry out the disproportionation of the chlorosilane efficiently.

The present invention relates to a process for the production of perhalogenated hexasilane anion by reacting halogenated monosilane in the presence of organosubstituted ammonium and/or phosphonium halide at temperatures in a range from 100 to 120° C., wherein no solvent is used, and a process for the production of a cyclic silane compound of the formula Si.sub.6R.sub.12, by reacting [X].sub.2[Si.sub.6Cl.sub.14] with AlR.sub.3 in at least one organic solvent, wherein R is chlorine or methyl and X, the same or different, is a counter-cation and is preferably selected from organosubstituted ammonium, organosubstituted phosphonium, alkali metal ions and [(PEDETA)(H.sub.2SiCl)]+.

The present invention relates to a process for the production of perhalogenated hexasilane anion by reacting halogenated monosilane in the presence of organosubstituted ammonium and/or phosphonium halide at temperatures in a range from 100 to 120° C., wherein no solvent is used, and a process for the production of a cyclic silane compound of the formula Si.sub.6R.sub.12, by reacting [X].sub.2[Si.sub.6Cl.sub.14] with AlR.sub.3 in at least one organic solvent, wherein R is chlorine or methyl and X, the same or different, is a counter-cation and is preferably selected from organosubstituted ammonium, organosubstituted phosphonium, alkali metal ions and [(PEDETA)(H.sub.2SiCl)]+.

The present invention relates to a process for preparing chlorinated oligosilanes, wherein chlorinated polysilane having an empirical formula of SiCl.sub.1.0-2.8 and/or a mixture comprising the chlorinated polysilane is reacted with elemental chlorine or a chlorine-containing mixture. Additionally claimed are chlorinated oligosilanes prepared by the process and the use thereof for production of semiconductors and/or hard coatings.

The present invention relates to a process for preparing chlorinated oligosilanes, wherein chlorinated polysilane having an empirical formula of SiCl.sub.1.0-2.8 and/or a mixture comprising the chlorinated polysilane is reacted with elemental chlorine or a chlorine-containing mixture. Additionally claimed are chlorinated oligosilanes prepared by the process and the use thereof for production of semiconductors and/or hard coatings.