US4911903A
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Spherical SIO2 particles
Assignee: Merck Patent GmbH
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Filing: 1988-07-12
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Granted: 1990-03-27
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Expires: 2008-07-12
Abstract
Abstract Highly monodispersed nonporous spherical SiO 2 particles are prepared having mean particle diameters between 0.05 and 10 μm with a standard deviation of not more than 5% and a method for the preparation of such particles. The particles can be produced by a two step process wherein first a sol of primary particles is prepared by hydrolytic polycondensation of tetraalkoxysilanes in an aqueous/alcoholic ammoniacal medium. The SiO 2 particles are then converted to the desired particle size by a continuous measured addition of tetraalkoxysilane or organotrialkoxysilane controlled by the extent of the reaction. The SiO 2 particles produced by this process are particularly useful as sorption material in chromatography.
Inventors
- 👤 Klaus Unger
- 👤 Herbert Giesche
- 👤 Joachim Kinkel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:50
CPC Classifications
B; B01; B01D; B01D15/00; B01D15/08; B01D15/26; B01D15/32; B01D15/325; B01J; B01J20/00; B01J20/02; B01J20/10; B01J20/103; B01J20/28; B01J20/28002; B01J20/28004; B01J20/28014; B01J20/28016; B01J20/28019; B01J20/28054; B01J20/28057; B01J20/28059; B01J20/281; B01J20/286; B01J20/287; B01J20/30; B01J20/3092; B01J20/32; B01J20/3202; B01J20/3204; B01J20/3214; B01J20/3217; B01J20/3231; B01J20/3242; B01J20/3244; B01J20/3246; B01J20/3257; B01J20/3259; B01J20/3261; B82; B82Y; B82Y30/00; C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/16; C01B33/163; C01B33/18; B01J2220/00; B01J2220/50; B01J2220/54; B01J2220/58; C01P; C01P2004/00; C01P2004/30; C01P2004/32; C01P2004/51; C01P2004/52; C01P2004/60; C01P2004/61; C01P2004/62; C01P2004/64; C01P2006/00; C01P2006/12
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
43 words
Substantially spherical SiO 2 particles having a mean particle diameter of between 0.05 and 10 μm with a standard deviation of not more than 5%, said particles being substantially nonporous, and said particles having a BET surface area of 1.1-64 m 2 /g.
Claim 2
Dependent Claim
43 words
Substantially spherical SiO 2 particles having a mean particle diameter of between 0.05 and 10 μm with a standard deviation of not more than 5%, said particles being substantially nonporous, and said particles having a BET surface area of 1.1-64 m 2 /g.
Claim 3
Dependent Claim
123 words
Substantially spherical SiO 2 particles having a mean particle diameter of between 0.05 and 10 μm, with a standard deviation of not more than 5%, said particles being substantially nonporous and having a BET surface area of 1.1-64 m 2 /g, wherein said particles are prepared by the process of continuously adding to a sol of primary particles formed by hydrolytic polycondensation of a tetraalkoxysilane in an aqueous/alcoholic ammoniacal hydrolysis mixture, an amount of a tetraalkoxysilane sufficient to lower the porosity of the particles in the sol, said continuous addition being effected at a rate whereby substantially no additional particles are formed and wherein the amount of silane added to the sol is controlled to directly control a resulting increase in particle size.
Claim 4
Dependent Claim
123 words
Substantially spherical SiO 2 particles having a mean particle diameter of between 0.05 and 10 μm, with a standard deviation of not more than 5%, said particles being substantially nonporous and having a BET surface area of 1.1-64 m 2 /g, wherein said particles are prepared by the process of continuously adding to a sol of primary particles formed by hydrolytic polycondensation of a tetraalkoxysilane in an aqueous/alcoholic ammoniacal hydrolysis mixture, an amount of a tetraalkoxysilane sufficient to lower the porosity of the particles in the sol, said continuous addition being effected at a rate whereby substantially no additional particles are formed and wherein the amount of silane added to the sol is controlled to directly control a resulting increase in particle size.
Claim 5
Dependent Claim
28 words
Substantially spherical SiO 2 particles according to claim 1, wherein said BET surface area of the particles formed is about 1 to 1.5 times their theoretical surface area.
Claim 6
Dependent Claim
28 words
Substantially spherical SiO 2 particles according to claim 2, wherein said BET surface area of the particles formed is about 1 to 1.5 times their theoretical surface area.
References Cited (Backward Citations)
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