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US4620023A
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Method for preparing hexamethylcyclotrisiloxane and uses for the same
Assignee: Consortium fuer Elektrochemische Industrie GmbH
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Filing: 1983-08-17
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Granted: 1986-10-28
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Expires: 2003-08-17
Abstract
Abstract Hexamethylcyclotrisiloxane is prepared by heating linear, branched, or cross-linked organopolysiloxanes containing at least 50 mol percent of dimethylsiloxane units to at least 350° C. in the absence of substances which attack the siloxane group during heating and simultaneously distilling off the cyclic dimethylpolysiloxanes thus formed. The hexamethylcyclotrisiloxane thus prepared is an excellent carrier for fragrant materials, especially where the carrier is present in admixture with other carrier substances such as tetramethylcyclobutanedione.
Inventors
- 👤 Franz-Heinrich Kreuzer
- 👤 Helmut Gebauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:31
CPC Classifications
C; C07; C07F; C07F7/00; C07F7/02; C07F7/08; C07F7/0834; C07F7/0838; C07F7/0872; C07F7/0874; A; A61; A61L; A61L9/00; A61L9/01; A61L9/015; A61L9/04; A61L9/044; C07F7/21
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
57 words
An improved method for preparing hexamethylcyclotrisiloxane by heating linear, branched, or cross-linked organopolysiloxanes having at least 50 mol percent of dimethylpolysiloxane units to at least 320° C. and simultaneously distilling off the cyclic dimethylpolysiloxanes formed during heating, the improvement which comprises heating the organopolysiloxanes in the absence of acidic and basic compounds which attack the siloxanes group.
Claim 2
Dependent Claim
57 words
An improved method for preparing hexamethylcyclotrisiloxane by heating linear, branched, or cross-linked organopolysiloxanes having at least 50 mol percent of dimethylpolysiloxane units to at least 320° C. and simultaneously distilling off the cyclic dimethylpolysiloxanes formed during heating, the improvement which comprises heating the organopolysiloxanes in the absence of acidic and basic compounds which attack the siloxanes group.
Claim 3
Dependent Claim
35 words
The improved method of claim 1, in which the organopolysiloxane is heated to at least 350° C. in a vessel made of iron or steel, copper, nickel, or chronium or alkali-free alloys of these metals.
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) | 1989-10-27 | 1990-04-28 | 1990-10-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-10-27 | 1994-04-28 | 1994-10-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-10-27 | 1998-04-28 | 1998-10-28 | $7700.00 | Window Closed / Lapsed |