US3846464A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing cyclic methylvinylsiloxanes
Assignee: General Electric Co
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Filing: 1973-11-27
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Granted: 1974-11-05
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Expires: 1993-11-27
Abstract
Abstract Cyclic sym-tetramethyltetravinyltetrasiloxane is prepared by cracking a methylvinylpolysiloxane hydrolysis product in admixture with an excess of a high boiling hydrocarbon solvent using heat and potassium hydroxide as the catalyst. The process provides high yields without the need for expensive catalysts and solvents and potentially hazardous reaction conditions.
Inventors
- 👤 J Razzano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:36
CPC Classifications
C; C07; C07F; C07F7/00; C07F7/02; C07F7/21
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
59 words
A PROCESS FOR THE PREPARATION OF SYMTETRAMETHYLTETRAVINYLCYCLOTETRASILOXANE COMPRISING THE HEATING OF A MIXTURE OF 1 PART OF (I) A HYDROLYSIS PRODUCT PF 99 TO 95 PARTS OF METHYLVINYKLDICHLOROSILANE AND FROM 1 TO 99 PARTS OF VUNYLTRICHLOROSILANE AND (II) AT LEAST 2 PARTS OF A HIGH BOILI HYDROCARBON SOLVENT IN THE PRESENCE OF AN EFFECTIVE, CATALYTIC AMOUNT OF POTASSIUM HYDROXIDE.
Claim 2
Dependent Claim
59 words
A PROCESS FOR THE PREPARATION OF SYMTETRAMETHYLTETRAVINYLCYCLOTETRASILOXANE COMPRISING THE HEATING OF A MIXTURE OF 1 PART OF (I) A HYDROLYSIS PRODUCT PF 99 TO 95 PARTS OF METHYLVINYKLDICHLOROSILANE AND FROM 1 TO 99 PARTS OF VUNYLTRICHLOROSILANE AND (II) AT LEAST 2 PARTS OF A HIGH BOILI HYDROCARBON SOLVENT IN THE PRESENCE OF AN EFFECTIVE, CATALYTIC AMOUNT OF POTASSIUM HYDROXIDE.
Claim 3
Dependent Claim
17 words
A process as defined in claim 1 wherein said high boiling hydrocarbon solvent is a mineral oil.
Claim 4
Dependent Claim
70 words
A process for the preparation of sym-tetramethyltetravinylcyclotetrasiloxane from the hydrolysis product of methyvinyldichlorosiloxane comprising: A. forming a mixture comprising i. 1 part of the dried hydrolysis product of methylvinyldichlorosilane; ii. at least three parts of a high boiling hydrocarbon solvent; and iii. from 0.5 to 5 percent by weight of potassium hydroxide, based on (i); B. heating the mixture; and C. distilling from the heated mixture a blend of sym-methylvinylcyclopolysiloxanes.
Claim 5
Dependent Claim
70 words
A process for the preparation of sym-tetramethyltetravinylcyclotetrasiloxane from the hydrolysis product of methyvinyldichlorosiloxane comprising: A. forming a mixture comprising i. 1 part of the dried hydrolysis product of methylvinyldichlorosilane; ii. at least three parts of a high boiling hydrocarbon solvent; and iii. from 0.5 to 5 percent by weight of potassium hydroxide, based on (i); B. heating the mixture; and C. distilling from the heated mixture a blend of sym-methylvinylcyclopolysiloxanes.
Claim 6
Dependent Claim
24 words
A process as defined in claim 3 wherein said hydrolysis product (i) is added to the distillation mixture as the cyclic polysiloxanes are removed.
Claim 7
Dependent Claim
18 words
A process as defined in claim 3 wherein the high boiling hydrocarbon solvent is a mineral oil solvent.
Claim 8
Dependent Claim
27 words
A process as defined in claim 3 wherein the amount of high boiling hydrocarbon solvent is from 3 to 5 times the amount of the hydrolysis product.
Claim 9
Dependent Claim
21 words
A process as defined in claim 3 wherein the potassium hydroxide comprises 2 to 4 percent by weight, based on (i).
Claim 10
Dependent Claim
18 words
A process as defined in claim 1 wherein a portion of the hydrolysis product of methylvinyldichlorosilane comprises sym-polymethylvinylcyclopolysiloxanes.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-04 | 1978-05-06 | 1978-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-04 | 1982-05-06 | 1982-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-04 | 1986-05-06 | 1986-11-05 | $7700.00 | Window Closed / Lapsed |