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US4895968A
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Acid equilibration method for organcpolysiloxanes having carbon-silicon-bonded aromatic organic radicals
Assignee: General Electric Co
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Filing: 1988-10-24
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Granted: 1990-01-23
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Expires: 2008-10-24
Abstract
Abstract A method is provided for the acidic equilibration of aromatic organic-substituted siloxanes, such as diphthalic anhydrode tetraorganicsiloxane with poly(aliphatic organicsiloxane) without significant cleavage of carbon-silicon-bonded aromatic organic radicals. A reduction in the generation of aromatic organic compounds, such as phthalic anhydride, can be achieved by effecting equilibration by adding the aromatic organic-substituted siloxane to a preformed mixture of acid-catalyzed poly(aliphatic organicsiloxane).
Inventors
- 👤 Mark A. Buese
- 👤 Sandra A. Swint
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:00
CPC Classifications
C; C07; C07F; C07F7/00; C07F7/02; C07F7/08; C07F7/18; C08; C08G; C08G77/00; C08G77/04; C08G77/06; C08G77/10; C08G77/14
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
95 words
A method for equilibrating poly(aliphatic organicsiloxane) with organicpolysiloxane having aromatic organic radicals attached to silicon by carbon-silicon bonds, whereby the tendency of the aromatic organic radicals attached to silicon by carbon-silicon bonds to cleave is substantially reduced, which comprises: (1) heating with agitation, a mixture comprising poly(aliphatic organicsiloxane) and an effective amount of acidic equilibration catalyst until the equilibration catalyst is uniformly dispersed throughout the resulting mixture and (2) adding the organicpolysiloxane having aromatic organic radicals attached to silicon by carbon-silicon bonds to (1) and heating the resulting mixture with agitation until equilibration is effected.
Claim 2
Independent Claim
95 words
A method for equilibrating poly(aliphatic organicsiloxane) with organicpolysiloxane having aromatic organic radicals attached to silicon by carbon-silicon bonds, whereby the tendency of the aromatic organic radicals attached to silicon by carbon-silicon bonds to cleave is substantially reduced, which comprises: (1) heating with agitation, a mixture comprising poly(aliphatic organicsiloxane) and an effective amount of acidic equilibration catalyst until the equilibration catalyst is uniformly dispersed throughout the resulting mixture and (2) adding the organicpolysiloxane having aromatic organic radicals attached to silicon by carbon-silicon bonds to (1) and heating the resulting mixture with agitation until equilibration is effected.
Claim 3
Dependent Claim
23 words
A method in accordance with claim 1, where the organicpolysiloxane having aromatic organic radicals attached to silicon by carbon-silicon bonds is 4,4'-(tetramethyldisiloxane-1,3-diyl)diphthalic anhydride.
Claim 4
Dependent Claim
13 words
A method in accordance with claim 1, where the poly(aliphatic organicsiloxane) is hexamethyldisiloxane.
Claim 5
Dependent Claim
13 words
A method in accordance with claim 1, where the poly(aliphatic organicsiloxane) is octamethylcyclotetrasiloxane.
Claim 6
Dependent Claim
15 words
A method in accordance with claim 1, where the acidic equilibration catalyst is trifluoromethanesulfonic acid.
Claim 7
Dependent Claim
15 words
A method in accordance with claim 1, where the acidic equilibration catalyst is methanesulfonic acid.
Claim 8
Dependent Claim
15 words
A method in accordance with claim 1, where the equilibration catalyst is removed by distillation.
Claim 9
Dependent Claim
17 words
A method in accordance with claim 1, where the equilibration mixture is quenched with a metal oxide.
Claim 10
Dependent Claim
14 words
A method in accordance with claim 6 where the quenching agent is magnesium oxide.
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) | 1993-01-22 | 1993-07-24 | 1994-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-22 | 1997-07-24 | 1998-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-22 | 2001-07-24 | 2002-01-23 | $7700.00 | Window Closed / Lapsed |