Patent US2959761A successfully refreshed from Google Patents.
US4382071A
Expired / Lapsed
US
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Process of preparing silicon tetrafluoride by using hydrogen fluoride gas
Assignee: Central Glass Co Ltd
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Filing: 1981-07-01
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Granted: 1983-05-03
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Expires: 2001-07-01
Abstract
Abstract A process of preparing silicon tetrafluoride by introducing hydrogen fluoride gas into a dispersion of powdery silicon oxide material, which needs not to be pure SiO 2 , in sulfuric acid not lower than 65% in the concentration of H 2 SO 4 . The reaction takes place even at room temperature. By using amorphous silicon oxide material, the rate of reaction can be enhanced with better yield. Preferably, the concentration of H 2 SO 4 in the liquid phase of the reaction system is maintained above 80% to obtain SiF 4 containing little (SiF 3 ) 2 O.
Inventors
- 👤 Toyozo Otsuka
- 👤 Naomichi Kitsugi
- 👤 Teruo Fujinaga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:23
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/08; C01B33/107; C01B33/10705
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
92 words
A process of preparing silicon tetrafluoride, comprising the step of introducing hydrogen fluoride gas into a slurry obtained by dispersing a silicon oxide material in finely divided form in sulfuric acid wherein the principle component of said silicon oxide material is amorphous silicon oxide such that the concentration of H 2 SO 4 in the liquid phase of the reaction system never becomes lower than 65% before completion of reaction between hydrogen fluoride and silicon oxide wherein the reaction is carried out at a temperature between room temperature and about 55° C.
Claim 2
Dependent Claim
92 words
A process of preparing silicon tetrafluoride, comprising the step of introducing hydrogen fluoride gas into a slurry obtained by dispersing a silicon oxide material in finely divided form in sulfuric acid wherein the principle component of said silicon oxide material is amorphous silicon oxide such that the concentration of H 2 SO 4 in the liquid phase of the reaction system never becomes lower than 65% before completion of reaction between hydrogen fluoride and silicon oxide wherein the reaction is carried out at a temperature between room temperature and about 55° C.
Claim 3
Dependent Claim
15 words
A process according to claim 1, wherein said silicon oxide material is a natural mineral.
Claim 4
Dependent Claim
24 words
A process according to claim 2, wherein said silicon oxide material is selected from the group consisting of activated clay, opal and diatomaceous earth.
Claim 5
Dependent Claim
15 words
A process according to claim 1, wherein said silicon oxide material is a synthetic material.
Claim 6
Dependent Claim
22 words
A process according to claim 4, wherein said silicon oxide formed as a by-product in the preparation of cryolite from sodium hexafluorosilicate.
Claim 7
Dependent Claim
36 words
A process according to claim 1, wherein the weight ratio of H 2 SO 4 to SiO 2 in said slurry before the introduction of hydrogen fluoride gas is in the range from 3:1 to 10:1.
Claim 8
Dependent Claim
31 words
A process according to claim 1, wherein the concentration of H 2 SO 4 in the liquid phase of the reaction system is maintained above 80% until completion of the reaction.
Claim 9
Dependent Claim
31 words
A process according to claim 1, wherein the concentration of H 2 SO 4 in the liquid phase of the reaction system is maintained above 85% until completion of the reaction.
Claim 10
Dependent Claim
26 words
A process according to claim 1, wherein the introduction of hydrogen fluoride gas into said slurry is commenced while said slurry is maintained at room temperature.
References Cited (Backward Citations)
US2833628A
Cited
US2861872A
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GB1080662A
Cited
US3645678A
Cited
US3674431A
Cited
US4206189A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-05-02 | 1986-11-01 | 1987-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-02 | 1990-11-01 | 1991-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-02 | 1994-11-01 | 1995-05-03 | $7700.00 | Window Closed / Lapsed |