US4053565A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silica xerogels
Assignee: National Petro-Chemicals Corp
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Filing: 1974-01-28
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Granted: 1977-10-11
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Expires: 1994-01-28
Abstract
Abstract Silica xerogels having pore volumes greater than about 2.0 cc/g., the major portion of which volumes are provided by pores having pore diameters ranging from 300 to 600 A, and surface areas ranging from 200 to 500 m 2 /g. Xerogels having such cumulative pore volume, pore diameter distribution, and surface area characteristics are useful as supports for stereospecific catalysts for particle form olefin polymerization reactions effecting the production of low molecular weight, high melt index polyolefins.
Inventors
- 👤 Jerome H. Krekeler
- 👤 William Kirch
- 👤 Henri A. Aboutboul
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:08
CPC Classifications
C; C08; C08F; C08F10/00; C08F10/02; B; B01; B01J; B01J21/00; B01J21/06; B01J21/08; B01J35/00; B01J35/60; C01; C01B; C01B33/00; C01B33/113; B01J35/61; B01J35/615; B01J35/63; B01J35/638; B01J35/64; B01J35/647; B01J35/651; B01J35/66; B01J35/67
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
142 words
A silica xerogel having the following characteristics: a. a nitrogen pore volume greater than 1.96 cc/g. and up to 2.90 cc/g., said pore volume being equal to the volume of the pores in said gel having pore diameters of up to 600 A and being determined as that volume of nitrogen adsorbed by and condensed in the pores of said gel per gram of the dry gel at the normal boiling point of liquid nitrogen and at a relative pressure P/Po equal to 0.967 wherein P is the pressure of the nitrogen vapor over the gel and Po is the vapor pressure of liquid nitrogen; b. the major portion of said nitrogen pore volume being provided by pores having pore diameters within the range of from 300-600 A; and c. a surface area within the range of from 200-500 m 2 /g.
Claim 2
Dependent Claim
142 words
A silica xerogel having the following characteristics: a. a nitrogen pore volume greater than 1.96 cc/g. and up to 2.90 cc/g., said pore volume being equal to the volume of the pores in said gel having pore diameters of up to 600 A and being determined as that volume of nitrogen adsorbed by and condensed in the pores of said gel per gram of the dry gel at the normal boiling point of liquid nitrogen and at a relative pressure P/Po equal to 0.967 wherein P is the pressure of the nitrogen vapor over the gel and Po is the vapor pressure of liquid nitrogen; b. the major portion of said nitrogen pore volume being provided by pores having pore diameters within the range of from 300-600 A; and c. a surface area within the range of from 200-500 m 2 /g.
Claim 3
Dependent Claim
22 words
The silica xerogel of claim 1, wherein the nitrogen pore volume is within the range of from 2.35 cc/g. to 2.90 cc/g.
References Cited (Backward Citations)
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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) | 1980-10-10 | 1981-04-11 | 1981-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-10 | 1985-04-11 | 1985-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-10 | 1989-04-11 | 1989-10-11 | $7700.00 | Window Closed / Lapsed |