Patent US4423240A successfully refreshed from Google Patents.
US4423240A
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Methods for preparing cyclopolysiloxane
Assignee: General Electric Co
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Filing: 1982-04-12
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Granted: 1983-12-27
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Expires: 2002-04-12
Abstract
Abstract Cyclic polysiloxanes can be prepared by hydrolysis of dimethyldichlorosilane and water or aqueous hydrochloric acid in the presence of the anionic surfactant, sodium lauryl sulfate, to give good yields of cyclic polysiloxanes and minimal amounts of linear silanols.
Inventors
- 👤 Yaw D. Yeboah
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:44
CPC Classifications
C; C07; C07F; C07F7/00; C07F7/02; C07F7/08; C07F7/0834; C07F7/0838; C07F7/0872; C07F7/0874; C07F7/21; C08; C08G; C08G77/00; C08G77/04; C08G77/045
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
45 words
In a process for preparing cyclic dimethylsiloxanes of the formula: ([CH.sub.3 ].sub.2 SiO).sub.m where m predominantly equals a whole number 3-6, by hydrolysis and condensation of dimethyldichlorosilane, the improvement which comprises conducting the reaction in the presence of an effective amount of sodium lauryl sulfate.
Claim 2
Dependent Claim
45 words
In a process for preparing cyclic dimethylsiloxanes of the formula: ([CH.sub.3 ].sub.2 SiO).sub.m where m predominantly equals a whole number 3-6, by hydrolysis and condensation of dimethyldichlorosilane, the improvement which comprises conducting the reaction in the presence of an effective amount of sodium lauryl sulfate.
Claim 3
Dependent Claim
16 words
The process as in claim 1 wherein the temperature of reaction is from about 10°-65° C.
Claim 4
Dependent Claim
32 words
The process as in claim 1 wherein the sodium lauryl sulfate is present in an amount ranging from about 0.05 to 2%, by weight, based on the weight of the aqueous feed.
Claim 5
Dependent Claim
26 words
The process as in claim 1 wherein the hydrolyzing agent is an aqueous phase containing from 0% HCl to a saturated solution of HCl in water.
Claim 6
Dependent Claim
27 words
The process as in claim 1 wherein the water to dimethyldichlorosilane molar ratio is between 1 to 4 moles of the former per mole of the latter.
References Cited (Backward Citations)
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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) | 1986-12-26 | 1987-06-27 | 1987-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-26 | 1991-06-27 | 1991-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-26 | 1995-06-27 | 1995-12-27 | $7700.00 | Window Closed / Lapsed |