Patent US2825453A successfully refreshed from Google Patents.
Patent US4866556A successfully refreshed from Google Patents.
Patent US4412081A successfully refreshed from Google Patents.
US4412081A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Methods for preparing decamethyl cyclopentasiloxane
Assignee: General Electric Co
•
Filing: 1982-08-27
•
Granted: 1983-10-25
•
Expires: 2002-08-27
Abstract
Abstract Decamethyl cyclopentasiloxane can be prepared in good yields by treatment of octamethylcyclotetrasiloxane with aqueous hydrochloric acid and a normal C 6-16 alkyl sulfonic acid.
Inventors
- 👤 Robert E. Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:24
CPC Classifications
C; C07; C07F; C07F7/00; C07F7/02; C07F7/21
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
55 words
A process for preparing a cyclic pentamer siloxane of the general formula [(CH.sub.3).sub.2 SiO].sub.5 from octamethyl cyclotetrasiloxane by heating the latter with a normal C 6-16 alkyl sulfonic acid having the formula n-C.sub.x H.sub.(2x+1) SO.sub.3 H where x=6 to 16, inclusive, in the presence of aqueous HCl at a temperature in excess of 50° C.
Claim 2
Dependent Claim
55 words
A process for preparing a cyclic pentamer siloxane of the general formula [(CH.sub.3).sub.2 SiO].sub.5 from octamethyl cyclotetrasiloxane by heating the latter with a normal C 6-16 alkyl sulfonic acid having the formula n-C.sub.x H.sub.(2x+1) SO.sub.3 H where x=6 to 16, inclusive, in the presence of aqueous HCl at a temperature in excess of 50° C.
Claim 3
Dependent Claim
14 words
The process as in claim 1 wherein the reaction temperature is between 50°-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
15 words
The process as in claim 1 wherein the alkyl sulfonic acid is n-decyl sulfonic acid.
Claim 6
Dependent Claim
19 words
The process as in claim 1 wherein the time of reaction is from about 30 minutes to 3 hours.
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) | 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 |