Patent EP0221780A2 successfully refreshed from Google Patents.
EP0221780A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Porous silica microspheres having silanol-enriched and silanized surfaces
Assignee: Agilent Technologies Inc
•
Filing: 1986-10-31
•
Granted: —
•
Expires: 2006-10-31
Abstract
Abstract A chromatographic material having improved crush resistance and a high level of surface silanol groups comprises porous silica microspheres having an average diameter of about 0.5 to about 35 pm, substantially all of said microspheres having a diameter ranging from about 0.5 to about 1.5 times said average diameter: said microspheres comprising a plurality of substantially uniform-size colloidal particles, having a silica surface, arranged in an interconnected three-dimensional lattice; said colloidal particles occupying less than about 50 volume percent of said microspheres with the remaining volume being occupied by interconnected pores having substantially uniform pore size distribution; said microspheres having a total concentration of silanol groups from about 6 to about 16 µmol/m 2 . The material may be reacted with a silanizing agent to generate a completely silanized surface.
Inventors
- 👤 Joseph Jack Kirkland
- 👤 Jürgen Köhler
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 15:28
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/281; B01J20/286; B01J20/02; B01J20/10; B01J20/103; B01J20/282; B01J20/283; B01J2220/00; B01J2220/50; B01J2220/54
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
101 words
A chromatographic material comprising porous silica microspheres having an average diameter of about 0.5 to about 35 um, substantially all of said microspheres having a diameter ranging from about 0.5 to about 1.5 times said average diameter; said microspheres comprising a plurality of substantially uniform-size colloidal particles, having a silica surface, arranged in an interconnected three-dimensional lattice; said colloidal particles occupying less than about 50 volume percent of said microspheres with the remaining volume being occupied by interconnected pores having substantially uniform pore size distribution; said microspheres having a total concentration of silanol groups from about 6 to about 16 umol/m2.
Claim 2
Dependent Claim
101 words
A chromatographic material comprising porous silica microspheres having an average diameter of about 0.5 to about 35 um, substantially all of said microspheres having a diameter ranging from about 0.5 to about 1.5 times said average diameter; said microspheres comprising a plurality of substantially uniform-size colloidal particles, having a silica surface, arranged in an interconnected three-dimensional lattice; said colloidal particles occupying less than about 50 volume percent of said microspheres with the remaining volume being occupied by interconnected pores having substantially uniform pore size distribution; said microspheres having a total concentration of silanol groups from about 6 to about 16 umol/m2.
Claim 3
Dependent Claim
23 words
A chromatographic material as defined in claim 1 wherein the microspheres have an average diameter of from about 1.0 to about 10 um.
Claim 4
Dependent Claim
28 words
A chromatographic material as defined in claim 1 or claim 2, wherein the total concentration of silanol groups is from about 8 to about 16 µmol/m 2 .
Claim 5
Dependent Claim
33 words
A chromatographic material as defined in any one of claims 1 to 3 wherein substantially all of said microspheres have a diameter ranging from about 0.8 to about 1.2 times said average diameter.
Claim 6
Dependent Claim
95 words
A chromatographic material comprising improved porous silica microspheres having an average diameter of 0.5 to about 35 um, substantially all of said microspheres having a diameter ranging from about 0.5 to about 1.5 times said average diameter; said microspheres consisting essentially of a plurality of substantially uniform-size colloidal particles, having a silica surface, arranged in an interconnected three-dimensional lattice: said colloidal particles occupying less than about 50 volume percent of said microspheres with the remaining volume being occupied by interconnected pores having a substantially uniform pore size distribution; said microspheres having a completely silanized surface.
Claim 7
Dependent Claim
95 words
A chromatographic material comprising improved porous silica microspheres having an average diameter of 0.5 to about 35 um, substantially all of said microspheres having a diameter ranging from about 0.5 to about 1.5 times said average diameter; said microspheres consisting essentially of a plurality of substantially uniform-size colloidal particles, having a silica surface, arranged in an interconnected three-dimensional lattice: said colloidal particles occupying less than about 50 volume percent of said microspheres with the remaining volume being occupied by interconnected pores having a substantially uniform pore size distribution; said microspheres having a completely silanized surface.
Claim 8
Dependent Claim
15 words
a chromatographic material as defined in claim 5 wherein said silanized surface comprises trimethylsilyl groups.
Claim 9
Dependent Claim
85 words
A process for preparing a chromatographic material as defined in any of claims 1 to 4, comprising: contacting heat strengthened thermally-dehydroxylated porous silica microspheres having a surface concentration of silanol groups of less than bout 5.5 µmol/m 2 with water in the presence of HF or at least one basic activator selected from quaternary ammonium hydroxides, ammonium bases, and organic amines at a temperature of from about ambient temperature to about 100° C for sufficient time to generate the desired total concentration of silanol groups.
Claim 10
Dependent Claim
46 words
A process as defined in claim 7 wherein said heat strengthened silica microspheres have been sintered at a temperature sufficiently high to reduce the specific surface area of the particles by at least 10% below the value for the colloidal particles from which they are formed.
Claim 11
Dependent Claim
22 words
A process as defined in claim 7 or 8 wherein said basic activator comprises tetrabutylammonium hydroxide, ammonium hydroxide, ethylenediamine, n-propylamine or n-butylamine.
Claim 12
Dependent Claim
25 words
A process as defined in claim 7 or 8 wherein said HF is employed at a concentration of from about 200 to about 400 ppm.
Claim 13
Dependent Claim
60 words
A process for preparing the chromatographic material as defined in claim 5 or 6 which comprises performing the process defined in any of claims 7 to 10 whereafter the resulting porous silica microspheres are contacted with a silanizing agent at a temperature of from about 25 to about 100 0 C for sufficient time to generate a completely silanized surface.
Claim 14
Dependent Claim
14 words
A chromatographic material-made by the process defined in any of claims 7 to 11.
Claim 15
Independent Claim
34 words
An apparatus for use in chromatographic separation comprising a region through which materials to be separated are passed, said region comprising chromatographic material as defined in any of claims 1 to 6 or 12.
Claim 16
Independent Claim
25 words
A method of separating materials chromatographically wherein the stationary phase comprises a chromatographic material as defined in any of claims 1 to 6 or 12.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.