US4529707A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Detection of boron impurities in chlorosilanes
Assignee: General Electric Co
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Filing: 1982-09-21
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Granted: 1985-07-16
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Expires: 2002-09-21
Abstract
Abstract A method for preparing a chlorosilane sample to enable colorimetric detection of the presence of minute amounts of boron impurities is provided. Detection of boron impurities below five parts per billion is contemplated.
Inventors
- 👤 Harold R. Cowles
- 👤 William D. Kray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:40
CPC Classifications
G; G01; G01N; G01N31/00; G01N31/22; Y; Y10; Y10T; Y10T436/00; Y10T436/19; Y10T436/25; Y10T436/25375; Y10T436/255
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
142 words
A method for quantitative spectrophotometric analysis of boron impurities in a sample of chlorosilane comprising: (1) treating the chlorosilane sample with sufficient chlorine to ensure full chlorination of the boron impurities; (2) introducing a stoichiometrically large amount of a siloxane selected from the group consisting of cyclotrisiloxane, cyclotetrasiloxane, alkyl, aryl, halogenated alkyl and halogenated aryl substituted cyclotrisiloxanes and cyclotetrasiloxanes, polydimethylsiloxane fluids, and dimethyl-methylhydrogensiloxane copolymers to the sample to ensure reaction with substantially all the boron impurities to form borosiloxane compounds; (3) removing the chlorosilane in an inert, anhydrous atmosphere leaving a solid residue comprising siloxane and the borosiloxane compounds; (4) developing the solid residue for spectrophotometric analysis by adding a reagent which forms a colored complex with boron suitable for spectrophotometric analysis and is not inhibited by the presence of said siloxane; and (5) spectrophotometrically determining the boron content of said residue.
Claim 2
Independent Claim
142 words
A method for quantitative spectrophotometric analysis of boron impurities in a sample of chlorosilane comprising: (1) treating the chlorosilane sample with sufficient chlorine to ensure full chlorination of the boron impurities; (2) introducing a stoichiometrically large amount of a siloxane selected from the group consisting of cyclotrisiloxane, cyclotetrasiloxane, alkyl, aryl, halogenated alkyl and halogenated aryl substituted cyclotrisiloxanes and cyclotetrasiloxanes, polydimethylsiloxane fluids, and dimethyl-methylhydrogensiloxane copolymers to the sample to ensure reaction with substantially all the boron impurities to form borosiloxane compounds; (3) removing the chlorosilane in an inert, anhydrous atmosphere leaving a solid residue comprising siloxane and the borosiloxane compounds; (4) developing the solid residue for spectrophotometric analysis by adding a reagent which forms a colored complex with boron suitable for spectrophotometric analysis and is not inhibited by the presence of said siloxane; and (5) spectrophotometrically determining the boron content of said residue.
Claim 3
Dependent Claim
12 words
A method as defined in claim 1, wherein said chlorosilane is trichlorosilane.
Claim 4
Dependent Claim
13 words
A method as defined in claim 2, wherein said siloxane is a cyclotrisiloxane.
Claim 5
Dependent Claim
12 words
A method as defined in claim 3, wherein said cyclotrisiloxane is hexamethylcyclotrisiloxane.
Claim 6
Dependent Claim
19 words
A method as defined in claim 1, wherein said removal step (3) is an evaporation by dry nitrogen purge.
Claim 7
Dependent Claim
18 words
A method as defined in claim 1, wherein the spectrophotometric determination of step (5) is a colorimetric determination.
Claim 8
Dependent Claim
16 words
A method as defined in claim 6, wherein said reagent comprises quinalizarin and concentrated sulfuric acid.
Claim 9
Dependent Claim
25 words
A method as defined in claim 7, wherein said reagent comprises 1 part by weight quinalizarin dissolved in approximately 368 parts by weight sulfuric acid.
References Cited (Backward Citations)
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| 3.5 Years (Year 4) | 1988-07-15 | 1989-01-14 | 1989-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-15 | 1993-01-14 | 1993-07-16 | $3760.00 | Window Closed / Lapsed |
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