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

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).