US4919804A
Expired / Lapsed
US
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Ultrasound driven synthesis of reversed and normal phase stationary phases for liquid chromatography
Assignee: University of Florida
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Filing: 1989-05-01
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Granted: 1990-04-24
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Expires: 2009-05-01
Abstract
Abstract In a method for producing a reversed phase bonded metal oxide by reacting the metal oxide with a reactive silane, the improvement comprising conducting the reaction in the presence of ultrasonic waves.
Inventors
- 👤 John G. Dorsey
- 👤 Karen B. Sentell
- 👤 Karen W. Barnes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:52
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/281; B01J20/286; B01J20/287; B01D; B01D15/00; B01D15/08; B01D15/26; B01D15/32; B01D15/325; B01J20/30; B01J20/32; B01J20/3202; B01J20/3204; B01J20/3231; B01J20/3242; B01J20/3244; B01J20/3246
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
87 words
In a method for the production of a reversed phase bonded metal oxide particularly adapted for use as a packing in high performance liquid chromatography, said method comprising reacting said metal oxide, in which at least some of the oxide groups have been converted to hydroxyl groups, with a substituted or unsubstituted alkyl silane reactive with said hydroxyl groups to produce a silyated derivative of said metal oxide, the improvement comprising conducting said reaction in the presence of ultrasonic waves at a temperature below about 20° C.
Claim 2
Dependent Claim
87 words
In a method for the production of a reversed phase bonded metal oxide particularly adapted for use as a packing in high performance liquid chromatography, said method comprising reacting said metal oxide, in which at least some of the oxide groups have been converted to hydroxyl groups, with a substituted or unsubstituted alkyl silane reactive with said hydroxyl groups to produce a silyated derivative of said metal oxide, the improvement comprising conducting said reaction in the presence of ultrasonic waves at a temperature below about 20° C.
Claim 3
Dependent Claim
44 words
In a method according to claim 1, the additional improvement comprising conducting said reaction in the presence of an amount of 4-dimethylaminopyridine sufficient to react with any acidic by-product of said reaction and to act in forming a reactive intermediate at the silica-solution interface.
Claim 4
Dependent Claim
22 words
The method of claim 1 wherein said metal oxide is selected from the group consisting of silica, alumina, zirconia, titania, iron oxide.
Claim 5
Dependent Claim
11 words
The method of claim 1 wherein said metal oxide is silica.
Claim 6
Dependent Claim
12 words
The method of claim 1 wherein said reactive silane is a chlorosilane.
Claim 7
Dependent Claim
10 words
The method of claim 5 wherein said chlorosilane is dimethyloctadecylchlorosilane.
Claim 8
Dependent Claim
10 words
The method of claim 1 wherein said chlorosilane is trimethylchlorosilane.
Claim 9
Dependent Claim
37 words
The method of claim 1 wherein said ultrasonic waves have frequencies in the range of from about 20 kHz to about 10 MHz and acoustic wavelengths in the range of from about 7.6 to about 0.015 cm.
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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) | 1993-04-23 | 1993-10-23 | 1994-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-23 | 1997-10-23 | 1998-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-23 | 2001-10-23 | 2002-04-24 | $7700.00 | Window Closed / Lapsed |