US4855469A
Expired / Lapsed
US
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Preparation of cycloorganotrisilazanes
Assignee: Dow Silicones Corp
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Filing: 1988-11-09
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Granted: 1989-08-08
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Expires: 2008-11-09
Abstract
Abstract What is disclosed is a process for the rearrangement of cylcoorganopolysilazanes to cycloorganotrisilazanes using quaternary ammonium halides as a catalyst. The quaternary ammonium halide has the formula R i 4 NX where at least one R i is a group containing greater than 11 carbon atoms and X is a halogen atom. The rearrangement process is ran either as a batch or a continuous distillation procedure.
Inventors
- 👤 Gnaneshwar R. Baile
- 👤 John E. Herman
- 👤 Geoffrey M. Wyshak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:53
CPC Classifications
C; C07; C07F; C07F7/00; C07F7/02; C07F7/21
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
121 words
A process for the preparation of a cycloorganotrisilazane having the formula, (R.sub.2 SiNH).sub.3, from a cycloorganopolysilazane having the formula, (R.sub.2 SiNH).sub.y, or mixtures thereof, wherein each R is independently selected from a group consisting of hydrogen, alkyl, alkenyl, aryl, and alkaryl, and y has a value of 4 or greater, said process comprising heating the cycloorganopolysilazane in the presence of a catalyst to from the cycloorganotrisilazane, said catalyst being selected from a group consisting of quaternary ammonium halides, having the formula, R.sup.i.sub.4 NX, wherein each R i is independently selected from a group consisting of alkyl, alkenyl, aryl, and alkaryl, and at least one R i is a group containing greater than 11 carbon atoms; and X is a halogen atom.
Claim 2
Dependent Claim
121 words
A process for the preparation of a cycloorganotrisilazane having the formula, (R.sub.2 SiNH).sub.3, from a cycloorganopolysilazane having the formula, (R.sub.2 SiNH).sub.y, or mixtures thereof, wherein each R is independently selected from a group consisting of hydrogen, alkyl, alkenyl, aryl, and alkaryl, and y has a value of 4 or greater, said process comprising heating the cycloorganopolysilazane in the presence of a catalyst to from the cycloorganotrisilazane, said catalyst being selected from a group consisting of quaternary ammonium halides, having the formula, R.sup.i.sub.4 NX, wherein each R i is independently selected from a group consisting of alkyl, alkenyl, aryl, and alkaryl, and at least one R i is a group containing greater than 11 carbon atoms; and X is a halogen atom.
Claim 3
Dependent Claim
25 words
A process according to claim 1, wherein the cycloorganopolysilazane is heated in the presence of the catalyst at a temperature greater than about 90° C.
Claim 4
Dependent Claim
13 words
A process according to claim 2, further comprising separating and isolating the cycloorganotrisilazane.
Claim 5
Dependent Claim
16 words
A process according to claim 3, wherein separating and isolating the cycloorganotrisilazane is effected by distillation.
Claim 6
Dependent Claim
18 words
A process according to claim 4, wherein distillation of the cycloorganotrisilazane is effected as the cycloorganotrisilazane is forming.
Claim 7
Dependent Claim
36 words
A process according to claim 5, wherein the distillation of the cycloorganotrisilazane is conducted at a temperature of at least 100° C. to about 160° C. and a pressure of less than about 80 mm Hg.
Claim 8
Dependent Claim
35 words
A process according to claim 6, wherein the distillation of the cycloorganotrisilazane is conducted at a temperature of at least 115° C. to about 150° C. and a pressure of less than 40 mm Hg.
Claim 9
Dependent Claim
19 words
A process according to claim 7, wherein the catalyst is stable to a temperature of at least 150° C.
Claim 10
Dependent Claim
12 words
A process according to claim 8, wherein the catalyst is hexadecyltrimethylammonium bromide.
Claim 11
Dependent Claim
12 words
A process according to claim 7, wherein the catalyst is octadecyldimethylbenzylammonium chloride.
Claim 12
Dependent Claim
16 words
A process according to claim 7, wherein the cycloorganotrisilazane is cyclohexamethyltrisilazane and the cycloorganopolysilazane is cyclodimethylpolysilalzane.
Claim 13
Dependent Claim
16 words
A process according to claim 2, wherein the cycloorganotrisilazane is cyclohexamethyltrisilazane and the cycloorganopolysilazane is cyclodimethylpolysilazane.
Claim 14
Dependent Claim
12 words
A process according to claim 12, wherein the catalyst is hexadecyltrimethylammonium bromide.
Claim 15
Dependent Claim
12 words
A process according to claim 12, wherein the catalyst is octadecyldimethylbenzylammonium chloride.
Claim 16
Dependent Claim
21 words
A process according to claim 12, wherein the catalyst is stable at a temperature greater than or equal to 90° C.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-07 | 1993-02-06 | 1993-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-07 | 1997-02-06 | 1997-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-07 | 2001-02-06 | 2001-08-08 | $7700.00 | Window Closed / Lapsed |