Apparatus and method for the condensed phase production of trisilylamine
The present invention is directed to a condensed phase batch process for synthesis of trisilylamine (TSA). An improved synthesis method that incorporates a solvent to help promote a condensed-phase reaction between ammonia gas (or liquid) and liquified monochlorosilane (MCS) in good yields is described. This method facilitates the removal of the byproduct waste with little to no reactor down time, substantial reduction of down-stream solids contamination and high-purity product from first-pass distillation.
1. A process for preparing trisilylamine comprising:
(a) adding a solvent to a reactor vessel;
(b) adding monohalosilane into the solvent to form a solution;
(c) adding anhydrous ammonia into the solution to form a reaction mixture;
(d) forming trisilylamine in the reaction mixture;
(e) separating silylamines from the reaction mixture; and
(f) purifying trisilylamine;
wherein the solvent is anisole.
2. The process of claim 1 further comprising adjusting the solvent temperature prior to adding the monohalosilane into the solvent to form a solution.
3. The process of claim 1 wherein the reactor vessel is maintained at a pressure of about two atmospheres or less.
4. The process of claim 1 wherein the monohalosilane is selected from the group consisting of monofluorosilane, monochlorosilane, monobromosilane and monoiodosilane.
5. The process of claim 1 wherein the monohalosilane is monochlorosilane.
6. The process of claim 2 wherein the solvent temperature is adjusted from about 70° C. to about −78° C. prior to adding monochlorosilane into the solvent.
7. The process of claim 2 wherein the solvent temperature is adjusted from about 50° C. to about −20° C. prior to adding monochlorosilane into the solvent.
8. The process of claim 1 wherein the molar ratio of monohalosilane to anhydrous ammonia is from about 1.05:1 to about 3:1.
9. A process for preparing trisilylamine comprising:
(a) adding a solvent to a reactor vessel;
(b) adding monohalosilane into the solvent to form a solution;
(c) adding anhydrous ammonia into the solution to form a reaction mixture;
(d) forming trisilylamine in the reaction mixture;
(e) separating trisilylamine from the reaction mixture; and
(f) purifying the trisilylamine;
wherein the solvent is anisole, the monohalosilane is monochlorosilane.
10. The process of claim 9 further comprising adjusting the solvent temperature prior to adding the monohalosilane into the solvent to form a solution.
11. The process of claim 10 wherein the solvent temperature is adjusted from about 50° C. to about −20° C. prior to adding monochlorosilane into the solvent.
12. The process of claim 9 wherein the molar ratio of monohalosilane to anhydrous ammonia is from about 1.05:1 to about 3:1.