Porous silica having high pore volume and methods of making and using same

Patent metadata

Field	Value
Publication number	US-9943826-B2
Application number	US-201414497796-A
Country	US
Kind code	B2
Filing date	Sep 26, 2014
Priority date	Sep 26, 2013
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

Silica particles, and methods of making and using silica particles are disclosed herein. In some embodiments, the silica particles are hollow, include an outer shell portion having a mesoporous structure, and have a pore volume of at least 4 cm 3 /g. In some embodiments, the silica particles include an outer shell portion having a mesoporous structure forming a cavity, the silica particles have an average pore diameter of 3 to 100 nm, and at least a portion of the silica particles include one or more core nanoparticles within the cavity. Silica particles as disclosed herein can be useful in a wide variety of applications such as selective separations (e.g., gas separations or purifications) based on structure.

First claim

What is claimed is:

1. Hollow silica particles comprising an outer shell portion having a mesoporous structure, wherein the hollow silica particles have a pore volume of at least 4 cm 3 /g, wherein the pore volume is determined by nitrogen physisorption at partial pressures of P/P o of 0.99.

2. The hollow silica particles of claim 1 , wherein the hollow silica particles have an average pore diameter of 3 to 100 nm as determined by Barrett-Joyner-Halenda/Kruk-Jaroniec-Sayari (BJH/KJS) nitrogen physisorption measurements, transmission electron microscopy (TEM), and small angle x-ray scattering (SAXS).

3. The hollow silica particles of claim 1 , wherein the hollow silica particles have an average particle diameter of 20 to 10,000 nm as determined by transmission electron microscopy (TEM), and a polydispersity index of 0.005 to 0.200 as determined by dynamic light scattering (DLS).

4. The hollow silica particles of claim 1 , wherein the hollow silica particles have an outer shell portion with an average thickness of 3 to 100 nm.

5. The hollow silica particles of claim 1 , wherein the hollow silica particles have a surface area of at least 1200 m 2 /g as measured by BET theory.

6. The hollow silica particles of claim 1 , wherein the hollow silica particles exhibit a small angle x-ray scattering pattern in which one or more peaks are observed at a diffraction angle corresponding to a range of d=2 to 100 nm.

7. The hollow silica particles of claim 1 , wherein a ratio of the thickness of the outer shell portion of the hollow silica particles to the average particle diameter is 0.0003 to 0.8.

8. A method for producing silica particles comprising an outer shell portion having a mesoporous structure, the method comprising:
preparing an aqueous mixture of components comprising at least one quaternary ammonium salt, at least one hydrophobic organic compound, at least one tertiary amine, and an aqueous medium;
agitating the aqueous mixture;
combining at least one silica source capable of forming a silanol compound by hydrolysis thereof with the agitated aqueous mixture under conditions effective to form hollow silica particles according to claim 1 ;
and removing excess components.

9. The method of claim 8 wherein the method further includes adding nanoparticles before or during agitation, and the method produces silica particles including an outer shell portion having a mesoporous structure forming a cavity, and wherein at least a portion of the silica particles include one or more core nanoparticles within the cavity.

10. The method of claim 8 , wherein the at least one quaternary ammonium salt is selected from the group consisting of a compound represented by the formula (1) and a compound represented by the formula (2):
[R 1 (CH 3 ) 3 N] + X −   (1)

[R 1 R 2 (CH 3 ) 2 N] + X −   (2),

wherein R 1 and R 2 are each independently a linear or branched alkyl group having 4 to 22 carbon atoms; and X is a monovalent anion.

11. The method of claim 8 , wherein the at least one tertiary amine is selected from the group consisting of a compound represented by the formula (3) and a compound represented by the formula (4):
R 1 (CH 3 ) 2 N  (3)

R 1 R 2 (CH 3 )N  (4),

wherein R 1 and R 2 are each independently a linear or branched alkyl group having 4 to 22 carbon atoms.

12. The method of claim 8 , wherein the at least one hydrophobic organic compound is selected from the group consisting of hydrocarbon compounds, ester compounds, fatty acids having 6 to 22 carbon atoms, and alcohols having 6 to 22 carbon atoms.

13. The method of claim 12 , wherein the at least one hydrophobic organic compound is a hydrocarbon compound selected from the group consisting of decane, squarane, squalene, perhydrosqualene, trimethyl benzene, triisopropyl benzene, isomers of xylene, toluene, benzene, a liquid paraffin, or a liquid petroleum jelly, and combinations thereof.

14. The method of claim 8 , wherein the aqueous medium comprises aqueous ammonium hydroxide.

15. The method of claim 8 , wherein the at least one silica source is selected from the group consisting of compounds represented by the following formulas (4), (5), (6), and (7):
R 3 SiY 3   (4);

R 3 2 SiY 2   (5);

R 3 3 SiY  (6); and

Y 3 Si—R 4 —SiY 3   (7),

wherein R 3 groups are each independently an organic group having a carbon atom directly bonded to a silicon atom; R 4 is a hydrocarbon group having 1 to 4 carbon atoms or a phenylene group; and Y is a monovalent hydrolyzable group that can be hydrolyzed into a hydroxyl group.

16. A method of using hollow silica particles comprising one or more of:
providing hollow silica particles according to claim 1 to support a catalyst;
providing hollow silica particles according to claim 1 as an adsorbent;
providing hollow silica particles according to claim 1 to separate a plurality of materials;
providing hollow silica particles according to claim 1 to deliver at least one drug; and
providing hollow silica particles according to claim 1 to adsorb environmental contaminants.

17. A method for high contrast biological/biomedical imaging comprising:
providing hollow silica particles according to claim 1 ; and
chemically modifying the hollow silica particles to enhance the contrast.

18. The method of claim 8 , wherein agitating comprises sonicating.

19. The method of claim 18 , wherein sonicating comprises sonicating at a temperature of 5 to 95° C.

20. The method of claim 8 , wherein agitating comprises stirring.

21. The method of claim 8 , wherein agitating comprising stirring and sonicating.

Assignees

• Univ Minnesota

Inventors

• Haynes Christy Lynn
• Egger Samuel Michael
• Datt Ashish

Classifications

• B01J21/08

  Silica · CPC title

• B01D53/02

  by adsorption, e.g. preparative gas chromatography {(solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01)} · CPC title

• B01J37/0018

  Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat) · CPC title

• B01J37/0072

  Preparation of particles, e.g. dispersion of droplets in an oil bath · CPC title

• B01J20/28021 Primary

  Hollow particles, e.g. hollow spheres, microspheres or cenospheres · CPC title