Method for producing siloxanes from alkali salts of silanols

Patent metadata

Field	Value
Publication number	US-10017526-B2
Application number	US-201515322775-A
Country	US
Kind code	B2
Filing date	Jun 29, 2015
Priority date	Jul 1, 2014
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

Cyclic siloxanes are prepared economically by reaction of an alkali metal siliconate having a mol ratio of alkali metal cation to silicon of less than one or their hydrolysis/condensation products or mixture thereof, with a halosilane.

First claim

The invention claimed is:

1. A process for preparing cyclic siloxanes of the formula (1)
[RSi(OSiR 1 R 2 R 3 )O] n   (1),

comprising:
reacting alkali metal salts of silanols of the formula (2),
R—Si(OH) 3-m (OM) m   (2),

wherein m is 0, 1, 2, or 3, and over all species of the alkali metal salts of silanols of the formula (2), m is on average 0.1 to <1,
their hydrolysis/condensation products, or alkali metal salts of silanols of the formula (2) together with their hydrolysis/condensation products, wherein the molar ratio of cation M to silicon is <1,
with halosilanes of the formula (3)
R 1 R 2 R 3 Si-Hal  (3)

where
n is 3, 4, 5, 6, 7 or 8,
R is an organic radical bonded via carbon to silicon,
M is an alkali metal cation,
Hal is a halogen radical, and
R 1 , R 2 , and R 3 are hydrogen, C 1-10 alkoxy radicals, C 1-20 aryloxy radicals or monovalent hydrocarbon radicals having 1 to 18 carbon atoms which are unsubstituted or substituted by halogen atoms or alkoxy groups,
and thereby producing cyclic siloxanes of the formula (1).

2. The process of claim 1 , wherein R is a monovalent, Si—C-bonded hydrocarbon radical having 1 to 30 carbon atoms, which is unsubstituted or substituted by halogen atoms, C 1-6 alkyl or C 1-6 alkoxy groups or silyl groups, and in which one or more mutually nonadjacent —CH 2 — units are optionally replaced by —O— or —S—.

3. The process of claim 1 , wherein M comprises sodium, potassium, or a mixture thereof.

4. The process of claim 2 , wherein M comprises sodium, potassium, or a mixture thereof.

5. The process of claim 1 , wherein the molar ratio M:Si in formula (2) is from 0.4 to 0.85.

6. The process of claim 2 , wherein the molar ratio M:Si in formula (2) is from 0.4 to 0.85.

7. The process of claim 3 , wherein the molar ratio M:Si in formula (2) is from 0.4 to 0.85.

8. The process of claim 1 , wherein the halosilanes of formula (3) are chlorosilanes.

9. The process of claim 2 , wherein the halosilanes of formula (3) are chlorosilanes.

10. The process of claim 3 , wherein the halosilanes of formula (3) are chlorosilanes.

11. The process of claim 5 , wherein the halosilanes of formula (3) are chlorosilanes.

12. The process of claim 1 , wherein reacting is carried out at 0° C. to 120° C.

13. The process of claim 2 , wherein reacting is carried out at 0° C. to 120° C.

14. The process of claim 3 , wherein reacting is carried out at 0° C. to 120° C.

15. The process of claim 5 , wherein reacting is carried out at 0° C. to 120° C.

16. The process of claim 8 , wherein reacting is carried out at 0° C. to 120° C.

17. The process of claim 1 , wherein reacting is carried out without auxiliary base.

18. The process of claim 2 , wherein reacting is carried out without auxiliary base.

19. The process of claim 3 , wherein reacting is carried out without auxiliary base.

20. The process of claim 5 , wherein reacting is carried out without auxiliary base.

21. The process of claim 1 , wherein n is 4.

Assignees

• Wacker Chemie Ag

Inventors

• Stepp Michael
• Koller Herbert

Classifications

• C07F7/21 Primary

  Cyclic compounds having at least one ring containing silicon, but no carbon in the ring · CPC title

• C07F7/0872

  Preparation and treatment thereof · CPC title