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US4764631A
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Preparation of cyclopolydiorganosiloxanes via vapor phase rearrangement
Assignee: Dow Silicones Corp
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Filing: 1988-01-15
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Granted: 1988-08-16
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Expires: 2008-01-15
Abstract
Abstract A process for preparing a product cyclopolydiorganosiloxane, (R 2 SiO) c . The process comprises (A) vaporizing a feed cyclopolydiorganosiloxane material, (R 2 SiO) x ; (B) passing the vapors from (A) through a heated bed of a solid catalyst, the catalyst comprising an alkali metal compound; (C) controlling pressure and temperature in the heated catalyst bed to favor formation of (R 2 SiO) c in an equilibrating mixture with other cyclopolydiorganosiloxanes; and (D) recovering an amount of the product cyclopolydiorganosiloxane, (R 2 SiO) c , which is substantially increased from the amount present in the feed cyclopolydiorganosiloxane material.
Inventors
- 👤 Roland L. Halm
- 👤 Sidney A. Hansen
- 👤 Charles E. Neal, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:55
CPC Classifications
C; C08; C08G; C08G77/00; C08G77/04; C08G77/045; C07; C07F; C07F7/00; C07F7/02; C07F7/21
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
60 words
A process for preparing a product cyclopolydiorganosiloxane, (R.sub.2 SiO).sub.c, wherein each R is independently selected from a group consisting of alkyl groups, alkenyl groups, aryl groups, and alkaryl groups; and c has a value of 3, 4, 5, 6, 7, 8, or 9, said process comprising (A) vaporizing a feed material consisting of a cyclopolydiorganosiloxane having the formula, (R.sub.2 SiO).sub.x
Claim 2
Dependent Claim
60 words
A process for preparing a product cyclopolydiorganosiloxane, (R.sub.2 SiO).sub.c, wherein each R is independently selected from a group consisting of alkyl groups, alkenyl groups, aryl groups, and alkaryl groups; and c has a value of 3, 4, 5, 6, 7, 8, or 9, said process comprising (A) vaporizing a feed material consisting of a cyclopolydiorganosiloxane having the formula, (R.sub.2 SiO).sub.x
Claim 3
Dependent Claim
96 words
wherein each R is defined above; and x is 3, 4, 5, 6, 7, 8, or 9, or a mixture of said cyclopolydiorganosiloxanes, (B) passing vapors of the feed material through a heated bed of a solid catalyst, said catalyst comprising an alkali metal compound; (C) controlling pressure and temperature in the heated catalyst bed to favor formation of (R 2 SiO) c in an equilibrating mixture with other cyclopolydiorganosiloxanes; and (D) recovering an amount of the product cyclopolydiorganosiloxane, (R 2 SiO) c , which is substantially increased from the amount present in the feed material.
Claim 4
Dependent Claim
96 words
wherein each R is defined above; and x is 3, 4, 5, 6, 7, 8, or 9, or a mixture of said cyclopolydiorganosiloxanes, (B) passing vapors of the feed material through a heated bed of a solid catalyst, said catalyst comprising an alkali metal compound; (C) controlling pressure and temperature in the heated catalyst bed to favor formation of (R 2 SiO) c in an equilibrating mixture with other cyclopolydiorganosiloxanes; and (D) recovering an amount of the product cyclopolydiorganosiloxane, (R 2 SiO) c , which is substantially increased from the amount present in the feed material.
Claim 5
Dependent Claim
31 words
A process according to claim 1, wherein the alkali metal compound is selected from a group consisting of sodium hydroxide, sodium carbonate, potassium hydroxide, potassium carbonate, cesium hydroxide, and cesium carbonate.
Claim 6
Dependent Claim
18 words
A process according to claim 1, wherein the catalyst is an alkali metal compound on a carbonaceous support.
Claim 7
Dependent Claim
22 words
A process according to claim 3, wherein the carbonaceous support is selected from a group consisting of activated carbon, coke, and charcoal.
Claim 8
Dependent Claim
25 words
A process according to claim 3, wherein the alkali metal compound is present at greater than about one percent of the weight of the catalyst.
Claim 9
Dependent Claim
25 words
A process according to claim 1, wherein temperature in the heated bed of solid catalyst is greater than the dew point of the feed material.
Claim 10
Dependent Claim
27 words
A process according to claim 1, wherein time required for the vapors to pass through the heated bed of solid catalyst is greater than about 0.5 seconds.
Claim 11
Dependent Claim
30 words
A process according to claim 1, wherein total water content of the feed material is in a range from about 50 to 100 parts per million on a weight basis.
Claim 12
Dependent Claim
16 words
A process according to claim 8, wherein additional water is fed with the feed cyclopolydiorganosiloxane material.
Claim 13
Dependent Claim
15 words
A process according to claim 1, wherein (R 2 SiO) c is recovered by distillation.
Claim 14
Dependent Claim
123 words
A process according to claim 1, wherein the feed material is [(CH 3 ) 2 SiO] x or a mixture thereof; wherein the solid catalyst is potassium hydroxide deposited on charcoal, said potassium hydroxide content of the catalyst being greater than about one weight percent; wherein the temperature in the heated bed of solid catalyst is greater than about 300° C.; wherein the pressure in the heated bed of solid catalyst is less than about 10 mm Hg.; wherein the time required for the vapors to pass through the heated bed of solid catalyst is greater than about 0.5 seconds; and wherein an amount of [(CH 3 ) 2 SiO] 3 substantially increased from the amount present in the feed material is recovered.
Claim 15
Dependent Claim
136 words
A process according to claim 11, wherein the total water content of the feed material is in a range from about 50 to 100 parts per million by weight; wherein the potassium hydroxide content of the catalyst is in a range from about 1 to 5 weight percent; wherein the temperature in the heated bed of solid catalyst is in a range of about 300° to 450° C. wherein the pressure in the heated bed of solid catalyst is in a range from about 5 to 10 mm Hg.; wherein the time required for the vapors to pass through the heated bed of solid catalyst is in a range from about 1 to 6 seconds; and wherein [(CH 3 ) 2 SiO] 3 is recovered at a purity greater than about 95 weight percent by distillation.
Claim 16
Dependent Claim
120 words
A process according to claim 1, wherein the feed material is [(CH 3 ) 2 SiO] x or a mixture thereof; wherein the solid catalyst is potassium hydroxide deposited on charcoal, said potassium hydroxide content of the catalyst being greater than about one weight percent; wherein the temperature in the heated bed of solid catalyst is about 200° C.; wherein the pressure in the heated bed of solid catalyst bed is about 100 mm Hg.; wherein the time required for the vapors to pass through the heated bed of solid catalyst is greater than about 0.5 seconds; and wherein an amount of [(CH 3 ) 2 SiO] 4 substantially increased from the amount present in the feed material is recovered.
Claim 17
Dependent Claim
95 words
A process according to claim 13, wherein the total water content of the feed material is in a range from about 50 to 100 parts per million by weight; wherein the potassium hydroxide content of the catalyst is in a range from about 1 to 5 weight percent; wherein the time required for the vapors to pass through the heated bed of solid catalyst is in a range from about 1 to 6 seconds; and wherein [(CH 3 ) 2 SiO] 4 is recovered at a purity greater than about 95 weight percent by distillation.
Claim 18
Dependent Claim
129 words
A process according to claim 1, wherein the feed material is [(CH 3 ) 2 SiO] x or a mixture thereof; wherein the solid catalyst is potassium hydroxide deposited on charcoal said potassium hydroxide content of the catalyst being greater than about one weight percent; wherein the temperature in the heated bed of solid catalyst is greater than about 200° C.; wherein the pressure in the heated bed of solid catalyst is greater than about 400 mm Hg.; wherein the time required for the vapors to pass through the heated bed of solid catalyst is greater than about 0.5 seconds; and wherein amounts of [(CH 3 ) 2 SiO] 5 and [(CH 3 ) 2 SiO] 6 substantially increased from the amounts present in the feed material are recovered.
Claim 19
Dependent Claim
141 words
A process according to claim 15, wherein the total water content of the feed material is in a range from about 50 to 100 parts per million by weight; wherein the potassium hydroxide content of the catalyst is in a range from about 1 to 5 weight percent; wherein the temperature in the heated bed of solid catalyst is in a range from about 200° to 300° C.; wherein the pressure in the heated bed of solid catalyst is in a range from about 500 to 1500 mm Hg.; wherein the time required for the vapors to pass through the bed of solid catalyst is in a range from about 1 to 6 seconds; and wherein [(CH 3 ) 2 SiO] 5 and [(CH 3 ) 2 SiO] 6 are recovered at purities greater than about 95 weight percent by distillation.
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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) | 1991-08-16 | 1992-02-15 | 1992-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-16 | 1996-02-15 | 1996-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-16 | 2000-02-15 | 2000-08-16 | $7700.00 | Window Closed / Lapsed |