Production of trisilylamine from monochlorosilane and ammonia by use of inert solvent

Patent metadata

Field	Value
Publication number	US-9617155-B2
Application number	US-201414212341-A
Country	US
Kind code	B2
Filing date	Mar 14, 2014
Priority date	Dec 16, 2011
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

The present invention relates to a specific process for producing trisilylamine from monochlorosilane and ammonia in the liquid phase. The invention further relates to a plant wherein such a process can be carried out with advantage.

First claim

The invention claimed is:

1. A process for preparing trisilylamine, comprising:
(i) adding a liquid solution comprising monochlorosilane and a solvent inert to monochlorosilane to a reactor,
wherein said liquid solvent is toluene;
wherein a volume ratio of solvent-to-monochlorosilane is in the range from 30:1 to 1:1;

(ii) adding ammonia dissolved in said solvent to the liquid solution to form a liquid reaction mixture,
wherein step (ii) is performed after step (i); and
wherein the monochlorosilane is present in a molar stoichiometric excess to the ammonia;

(iii) forming trisilylamine in the reaction mixture,
wherein the trisilylamine is formed in the reaction mixture at a temperature of −60 to +40° C, wherein the reaction is carried out at a pressure of 0.5 to 15 bar;

(iv) separating the trisilylamine from the reaction mixture by distillation in a distillation column to produce purified trisilylamine;
wherein the reactor is filled with the reaction mixture recycled from the distillation column.

2. The process of claim 1 , wherein the trisilylamine is formed in the reaction mixture at a temperature of −20 to +60° C.

3. The process of claim 1 , wherein the trisilylamine is formed in the reaction mixture at a temperature of −20 to +40° C.

4. The process of claim 1 , further comprising stirring in steps (i), (ii) and (iii).

5. A process for production of trisilylamine (TSA) in the liquid
phase, comprising:
initially charging monochlorosilane (A or A′) to a reactor ( 1 ) in the liquid form of a solution in a solvent (H), wherein the solvent is inert with regard to monochlorosilane, ammonia as well as TSA and has a higher boiling point than TSA has, wherein said liquid solvent is toluene, wherein a volume ratio of solvent-to-monochlorosilane is in the range from 30:1 to 1:1; and
passing ammonia (B) into the reactor in the form of a solution in the solvent (H), wherein the monochlorosilane is present in a molar stoichiometric excess to the ammonia,
performing the reaction in reactor ( 1 ), wherein the TSA is formed in the reaction mixture at a temperature of −60to +40° C., wherein the reaction is carried out at a pressure of 0.5 to 15 bar;
subsequently passing the resultant product mixture from reactor ( 1 ) into and through a filter unit ( 2 ) and removing solid ammonium chloride (C) from the product mixture, and
passing the filtrate from the filter unit ( 2 ) into the distillation column ( 3 ),
excess monochlorosilane (A′) being distilled in distillation column ( 3 ) overhead, condensed and fed to reactor ( 1 ) in liquid form under admixture of the solvent, and also
removing gaseous substances (D) from the distillation column ( 3 ) overhead, and
conveying the bottoms (E) into the distillation column ( 4 ),
the product trisilylamine (G) being distilled in the distillation column ( 4 ) overhead and condensed, and
conveying the bottoms (F) into the distillation column ( 5 ),
the solvent (H) being distilled in distillation column ( 5 ) overhead, condensed and returned to the reactor feedstreams (A), (A′), (B) as a solvent, and
exporting higher boilers via the bottoms (I).

Assignees

• Hoppe Carl-Friedrich
• Rauleder Hartwig
• Goetz Christian
• Evonik Degussa Gmbh

Inventors

• Hoppe Carl-Friedrich
• Rauleder Hartwig
• Goetz Christian

Classifications

• C01B21/087 Primary

  containing one or more hydrogen atoms · CPC title

• C01C1/164

  Ammonium chloride · CPC title