US4299731A
Expired / Lapsed
US
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Large pore volume olefin polymerization catalysts
Assignee: Phillips Petroleum Co
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Filing: 1980-02-06
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Granted: 1981-11-10
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Expires: 2000-02-06
Abstract
Abstract Large pore volume (≧1.4 cc/g) silica is obtained by slowly drying an acidic (pH≦3.5) silica hydrogel. The gel is useful in connection with chromium as an ethylene polymerization catalyst.
Inventors
- 👤 Max P. McDaniel
- 👤 John J. Meister
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:01
CPC Classifications
C; C08; C08F; C08F10/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
119 words
A process to produce an olefin polymerization catalyst comprising: (a) contacting an aqueous alkali metal silicate comprising solution with an acid to produce an alkali-containing hydrogel, (b) removing alkali from said alkali-containing hydrogel by washing with water to obtain a purified silica-containing hydrogel, (c) admixing the so obtained purified silica-containing hydrogel with acid to obtain an acidified silica-containing hydrogel having a pH of 3.5 or less, (d) maintaining said acidified silica-containing hydrogel at a temperature near the boiling point of water at the drying pressure until essentially all water is evaporated (e) prior to, during or after said drying utilizing a chromium source to obtain a chromium-containing gel, (f) recovering a chromium-containing xerogel as the product of the process.
Claim 2
Dependent Claim
119 words
A process to produce an olefin polymerization catalyst comprising: (a) contacting an aqueous alkali metal silicate comprising solution with an acid to produce an alkali-containing hydrogel, (b) removing alkali from said alkali-containing hydrogel by washing with water to obtain a purified silica-containing hydrogel, (c) admixing the so obtained purified silica-containing hydrogel with acid to obtain an acidified silica-containing hydrogel having a pH of 3.5 or less, (d) maintaining said acidified silica-containing hydrogel at a temperature near the boiling point of water at the drying pressure until essentially all water is evaporated (e) prior to, during or after said drying utilizing a chromium source to obtain a chromium-containing gel, (f) recovering a chromium-containing xerogel as the product of the process.
Claim 3
Dependent Claim
60 words
A process in accordance with claim 1 comprising: (a) reacting alkali metal silicates and a strong acid to produce an alkali ions-containing hydrogel, (b) washing said alkali ions-containing hydrogel to remove essentially all of the alkali ions to produce a purified hydrogel, (c) mixing said purified hydrogel and an acid to produce an acidic hydrogel, (d) drying said acidic hydrogel.
Claim 4
Dependent Claim
23 words
A process in accordance with claim 2 comprising aging said purified hydrogel prior to the mixing of said purified hydrogel with said acid.
Claim 5
Dependent Claim
13 words
A process in accordance with claim 1 comprising slowly drying said silica-containing hydrogel.
Claim 6
Dependent Claim
25 words
A process in accordance with claim 4 comprising dissolving said chromium compound in said acid and mixing the solution so obtained and said purified hydrogel.
Claim 7
Dependent Claim
35 words
A process in accordance with claim 1 comprising mixing said large pore volume xerogel and a solution of a chromium compound in an inert organic solvent and removing said solvent to obtain said chromium-containing xerogel.
Claim 8
Dependent Claim
15 words
A process in accordance with claim 1 wherein said silica-containing hydrogel consists essentially of silica.
Claim 9
Dependent Claim
28 words
A supported chromium polymerization catalyst produced by the process of claim 1 the support of which comprises silica xerogel having a pore volume of above about 1.4 cc/g.
Claim 10
Dependent Claim
25 words
A process in accordance with claim 1 wherein said step (b) is carried out under a radiant heat source or in a drying vacuum oven.
Claim 11
Dependent Claim
15 words
Process of claim 1 wherein said acid used in step (c) is an organic acid.
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) | 1984-11-09 | 1985-05-11 | 1985-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-09 | 1989-05-11 | 1989-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-09 | 1993-05-11 | 1993-11-10 | $7700.00 | Window Closed / Lapsed |