Process and apparatus for preparation of octachlorotrisilane

Patent metadata

Field	Value
Publication number	US-9845248-B2
Application number	US-201414782545-A
Country	US
Kind code	B2
Filing date	Mar 4, 2014
Priority date	Apr 24, 2013
Publication date	Dec 19, 2017
Grant date	Dec 19, 2017

Abstract

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.

First claim

The invention claimed is:

1. A process for preparing octachlorotrisilane, the process comprising
subjecting chlorosilanes comprising at least one monomeric chlorosilane of formula I in the absence of hydrogen to a thermal plasma:
H x SiCl 4−x   (I),

where x is independently selected from 0, 1, 2 and 3.

2. The process according to claim 1 , further comprising
obtaining a mixture of octachlorotrisilane and hexachlorodisilane.

3. The process according to claim 1 , further comprising
isolating ultrahigh-purity octachlorotrisilane.

4. The process according to claim 1 , further comprising
obtaining octachlorotrisilane having a titanium content of less than 1 ppm by weight.

5. The process according to claim 1 , wherein the the chlorosilanes are one or more of an ultrahigh-purity tetrachlorosilane, an ultrahigh-purity trichlorosilane, and an ultrahigh-purity dichlorosilane.

6. The process according to claim 1 , wherein the process is performed in an apparatus comprising a gas discharge reactor, a first column, and a second column.

7. The process according to claim 6 , wherein
the first column is provided with a column inlet for removal of octachlorotrisilane upstream of the gas discharge reactor and the second column is provided with a column inlet for removal of low boilers downstream of the gas discharge reactor and a column outlet,
the column outlet of the second colunm has a dedicated gas divider, and
the gas divider has a dedicated recycle line which supplies the low boilers to the first column or to the gas discharge reactor as a return stream.

8. The process according to claim 7 , wherein the gas divider has a shut-off, a valve, or other regulating unit.

9. The process according to claim 7 , wherein the chlorosilane of the formula I is introduced into the gas discharge reactor or supplied to the first column in a mixture with hexachlorodisilane.

10. The process according to claim 9 , wherein
unconverted mixture of the chlorosilanes of the formula I and hexachlorodisilane leaving the gas discharge reactor via the second column are divided in the apparatus at the gas divider,
a portion of the mixture is recycled as a return stream via the recyle line into the first column and conducted again through the gas discharge reactor, and
high-purity or ultrahigh-purity octachlorotrisilane is obtained at the column outlet of the first column.

11. The process according to claim 10 , wherein a molar ratio of trichlorosilane to tetrachlorosilane in the return stream is from 0.1:20 to 2:20.

12. The process according to claim 6 , wherein a pressure of 300 to 800 mbar abs exists in the gas discharge reactor.

Assignees

• Evonik Degussa Gmbh

Inventors

• Lang Juergen Erwin
• Rauleder Hartwig
• Mueh Ekkehard
• Moussallem Imad

Classifications

• C01B33/03

  by decomposition of silicon halides or halosilanes or reduction thereof with hydrogen as the only reducing agent · CPC title

• B01J19/087

  employing electric or magnetic energy · CPC title

• B01J2219/0875

  Gas · CPC title

• C01B33/10773

  Halogenated silanes obtained by disproportionation and molecular rearrangement of halogenated silanes · CPC title

• C01B33/107 Primary

  Halogenated silanes · CPC title