Electrolytic process to silicides

Patent metadata

Field	Value
Publication number	US-9469909-B2
Application number	US-201314410776-A
Country	US
Kind code	B2
Filing date	Jun 26, 2013
Priority date	Aug 30, 2012
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

An electrolytic process may be used to generate reactive metal silicides with Group 1 metals of the periodic table and/or Group 2 metals of the periodic table, and/or aluminum. Exemplary reactive metal silicides include magnesium silicide (Mg 2 Si).

First claim

The invention claimed is:

1. A process comprising:
(i) heating a salt comprising (a) a halide of a metal of formula MX a , where M is selected from the group consisting of Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al, and a combination thereof, subscript a is an integer of 1 or more, and each X is a halogen atom, thereby preparing a molten salt;
(ii) introducing to the molten salt, a gas comprising a silane of formula H b SiX (4-b) , where subscript b is an integer from 0 to 4, and passing an electric current through the molten salt, thereby producing an electrolysis product comprising a silicide of the metal.

2. The process of claim 1 , where one of conditions (a) and (b) is met, and
condition (a) is M is Al, K, Li, Mg, Na, or a combination thereof; or
condition (b) is M is Al, Ca, Mg, or a combination thereof.

3. The process of claim 1 , where the salt further comprises at least one of ingredients (b) and (c), where
ingredient (b) is a metal selected from Li, Na, K, Rb, Cs, Fr; Be, Mg, Ca, Sr, Ba, Ra, Al, or a combination thereof, and
ingredient (c) is an ionic liquid.

4. The process of claim 3 , where one of conditions (i) and (ii) is satisfied, and
condition (i) is (b), the metal, is Al, K, Li, Mg, Na, or a combination thereof; or
condition (ii) is (b), the metal, is Al, Ca, Mg, or a combination thereof.

5. The process of claim 1 , where b is 0 to 3.

6. The process of claim 1 , further comprising: drying the salt before step (i).

7. The process of claim 1 , where the gas in step (ii) further comprises H 2 .

8. The process of claim 1 , further comprising (iii) recovering a product comprising a metal silicide from the electrolysis product.

9. The process of claim 1 , where the process steps are performed under an inert gas atmosphere.

10. The process of claim 1 , where the electrolysis product comprises
(A) the metal silicide, and
(B) a second product comprising X 2 .

11. The process of claim 10 , further comprising: (iv) recovering the second product from the electrolysis product and optionally recycling the X 2 to a process for producing HX and/or to carbohalogenation reactions to generate SiX 4 .

12. The process of claim 10 , further comprising (v) reacting a halide of formula HX with the electrolysis product comprising the metal silicide, thereby preparing a reaction product comprising
(1) a product comprising one or more hydridosilanes of formulae SiH 4 , HSiX 3 , H 2 SiX 2 , and/or H 3 SiX; and
(2) a third product comprising MX a .

13. The process of claim 10 , further comprising (v) reacting the electrolysis product, with an aqueous acid, thereby preparing a reaction product comprising:
(1) a fourth product comprising one or more hydridosilanes of formulae SiH 4 , HSiX 3 , H 2 SiX 2 , or H 3 SiX; and/or polysilanes of formulae H c Si d X e , where subscript c is an integer of 1 or more, subscript d is an integer of 2 or more, and subscript e is an integer of 0 or more, and
(2) a fifth product comprising aqueous MX a .

14. The process of claim 13 , further comprising: dehydrating the aqueous MX a .

15. The process of claim 12 , further comprising (vi) recycling the MX a in step (i).

16. The process of claim 1 , where each X is Cl.

17. The process of claim 1 , where each M is Mg.

18. The process of claim 11 , further comprising (v) reacting a halide of formula HX with the electrolysis product comprising the metal silicide, thereby preparing a reaction product comprising
(1) a product comprising one or more hydridosilanes of formulae SiH 4 , HSiX 3 , H 2 SiX 2 , and/or H 3 SiX; and
(2) a third product comprising MX a .

19. The process of claim 11 , further comprising (v) reacting the electrolysis product (or the metal silicide recovered from the electrolysis product), with an aqueous acid, thereby preparing a reaction product comprising:
(1) a fourth product comprising one or more hydridosilanes of formulae SiH 4 , HSiX 3 , H 2 SiX 2 , or H 3 SiX; and/or polysilanes of formulae H c Si d X e , where subscript c is an integer of 1 or more, subscript d is an integer of 2 or more, and subscript e is an integer of 0 or more, and
(2) a fifth product comprising aqueous MX a .

20. The process of claim 14 , further comprising (vi) recycling the MX a in step (i).

Assignees

• Dow Corning

Inventors

• Katsoulis Dimitris
• Larsen Robert
• Morgan Robert

Classifications

• C25B1/18 Primary

  Alkaline earth metal compounds or magnesium compounds · CPC title

• C01B33/06

  Metal silicides (alloys C22) · CPC title

• C25B1/26

  Chlorine; Compounds thereof (by simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine C25B1/34) · CPC title

• C25B1/14

  Alkali metal compounds · CPC title

• C01B33/043

  Monosilane · CPC title