US4412080A
Expired / Lapsed
US
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Methods for preparing cyclopolysiloxanes
Assignee: General Electric Co
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Filing: 1982-08-16
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Granted: 1983-10-25
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Expires: 2002-08-16
Abstract
Abstract Cyclic methyl polysiloxanes can be prepared by hydrolysis of dimethyldichlorosilane and aqueous hydrochloric acid in the presence of a normal C 6-16 alkyl sulfonic acid to give good yields of cyclic polysiloxanes and minimal amounts of linear silanols.
Inventors
- 👤 Robert E. Williams, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:05
CPC Classifications
C; C07; C07F; C07F7/00; C07F7/02; C07F7/21
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
47 words
A process for preparing cyclic dimethylsiloxanes of the formula: [(CH.sub.3).sub.2 SiO].sub.m where m predominantly equals a whole number from 3-6, which comprises hydrolyzing dimethyldichlorosilane with a normal C 6-16 alkylsulfonic acid with aqueous HCl containing, by weight, from 20% to saturated aqueous HCl depending on the temperature.
Claim 2
Dependent Claim
47 words
A process for preparing cyclic dimethylsiloxanes of the formula: [(CH.sub.3).sub.2 SiO].sub.m where m predominantly equals a whole number from 3-6, which comprises hydrolyzing dimethyldichlorosilane with a normal C 6-16 alkylsulfonic acid with aqueous HCl containing, by weight, from 20% to saturated aqueous HCl depending on the temperature.
Claim 3
Dependent Claim
14 words
The process as in claim 1 wherein the reaction temperature is from 0°-100° C.
Claim 4
Dependent Claim
30 words
The process as in claim 1 wherein the sulfonic acid is present in an amount ranging from 0.1 to 2%, by weight, based on the weight of the aqueous HCl.
Claim 5
Dependent Claim
34 words
The process as in claim 1 wherein the water in the aqueous HCl to the dimethyldichlorosilane is in a molar ratio between 2 to 30 moles of the former per mole of the dimethyldichlorosilane.
Claim 6
Dependent Claim
31 words
The process for making octamethylcylcotetrasiloxane which comprises hydrolyzing dimethyldichlorosilane in the presence of a normal C 6-16 alkyl sulfonic acid, with from 20-36% aqueous HCl at a temperature below 50° C.
Claim 7
Dependent Claim
31 words
The process for making octamethylcylcotetrasiloxane which comprises hydrolyzing dimethyldichlorosilane in the presence of a normal C 6-16 alkyl sulfonic acid, with from 20-36% aqueous HCl at a temperature below 50° C.
Claim 8
Dependent Claim
15 words
The process as in claim 5 wherein the alkyl sulfonic acid is n-octyl sulfonic acid.
Claim 9
Dependent Claim
44 words
The process for making decamethylcyclopentasiloxane which comprises hydrolyzing dimethyldichlorosilane in the presence of a normal C 6-16 alkyl sulfonic acid with aqueous HCl containing by weight 20-36% HCl at a temperature in excess of 50° C. and for a time greater than 0.5 hour.
Claim 10
Dependent Claim
44 words
The process for making decamethylcyclopentasiloxane which comprises hydrolyzing dimethyldichlorosilane in the presence of a normal C 6-16 alkyl sulfonic acid with aqueous HCl containing by weight 20-36% HCl at a temperature in excess of 50° C. and for a time greater than 0.5 hour.
Claim 11
Dependent Claim
19 words
The process as in claim 7 wherein the alkyl sulfonic acid is C 10 H 21 SO 3 H.
References Cited (Backward Citations)
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US3763212A
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US4276425A
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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) | 1986-10-24 | 1987-04-25 | 1987-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-24 | 1991-04-25 | 1991-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-24 | 1995-04-25 | 1995-10-25 | $7700.00 | Window Closed / Lapsed |