SiO2-layered double hydroxide microspheres and methods of making them

Patent metadata

Field	Value
Publication number	US-10773246-B2
Application number	US-201615541655-A
Country	US
Kind code	B2
Filing date	Jan 6, 2016
Priority date	Jan 6, 2015
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

A method of making silica-layered double hydroxide microspheres having the formula I: (i) wherein, M z+ and M′ y+ are two different charged metal cations; z=1 or 2; y=3 or 4; 0<x<0.9; b is 0 to 10; c is 0 to 10; P>0, q>0, X n− is an anion; with n>0 a=z(1−x)+xy−2; and the AMO-solvent is an 100% aqueous miscible organic solvent; comprises the steps: (a) contacting silica microspheres and a metal ion containing solution containing metal ions M z+ and M′ y+ in the presence of a base and an anion solution; (b) collecting the product; and (c) optionally treating the product with AMO-solvent and recovering the solvent treated material to obtain the silica-layered double hydroxide microspheres. Preferably, M in the formula I is Li, Mg, Ni or Ca. Preferably, M′ in formula I is Al. The invention further provides silica-layered double hydroxide microspheres having the formula I. The silica-layered double hydroxide microspheres may be used as catalysts and/or catalyst supports.

(SiO 2 ) p @{[M z+ (1-x) M′ y+ x (OH) 2 ] a+ (X n− ) a/n .b H 2 O. c (AMO-solvent)} q   (I)

First claim

The invention claimed is:

1. A method of making silica-layered double hydroxide microspheres, each having a silica microsphere core and a layered double hydroxide coating on the surface of the silica microsphere core, the silica-layered double hydroxide microspheres having the formula I
(SiO 2 ) p @{[M z+ (1-x) M  y+ x (OH) 2 ] a+ (X n− ) a/n .b H 2 O. c (AMO-solvent)} q   (I)

wherein,
M z+ and M′ y+ are two different charged metal cations;
z=1 or 2;
y=3 or 4;
0<x<0.9;
b is 0 to 10;
c is 0 to 10;
p>0,
q>0,
X n− is an anion; with n>0
a=z(1−x)+xy−2; and
the AMO-solvent is an 100% aqueous miscible organic solvent;
which method comprises the steps:
(a) contacting:
(i) silica microspheres,
(ii) a metal ion containing solution containing metal ions M z+ and M′ y+ , and
(iii) an anion solution
in the presence of a base to grow a layered double hydroxide coating on the surface of the silica microspheres;
(b) collecting the product; and
(c) optionally treating the product with AMO-solvent and recovering the solvent treated material to obtain the silica-layered double hydroxide microspheres;
wherein the pH of the reaction solution formed in step (a) is controlled within a range from 8 to 12;
and wherein the silica-layered double hydroxide microspheres have a thickness of layered double hydroxide of larger than 110 nm.

2. The method according to claim 1 , wherein M′ is one or more trivalent metal cations.

3. The method according to claim 1 , wherein M is one or more divalent metal cations.

4. The method according to claim 1 , wherein X n− is selected from CO 3 2− , OH − , F − , Cl − , Br − , I − , SO 4 2− , NO 3 − and PO 4 3− , or a mixture thereof.

5. The method according to claim 1 , wherein M is Mg, M′ is Al and X n− is CO 3 2− .

6. The method according to claim 1 , wherein the pH is controlled within a range from 9 to 10.

7. The method according to claim 1 , wherein the product collected in step (b) is dispersed in the AMO-solvent and wherein c in the formula I has a value which is greater than zero and up to 10.

8. The method according to claim 7 , wherein the dispersion of the product in the AMO-solvent is maintained for 2 or more hours and then the treated material is separated from the solvent.

9. The method according to claim 1 , wherein the AMO-solvent is acetone, ethanol or methanol or a mixture thereof.

10. The method according to claim 1 , wherein the temperature of the metal ion containing solution in step (a) is within a range of from 20 to 150° C.

11. The method according to claim 10 , wherein the temperature is from 20 to 80° C.

12. The method of claim 1 , wherein the silica-layered double hydroxide microspheres have specific surface area as determined by N 2 BET of at least 177 m 2 /g.

13. The method of claim 1 , wherein the silica-layered double hydroxide microspheres have at least one structure from hollow-shell, yolk-shell and solid core-shell structures.

14. The method of claim 1 , wherein step (a) comprises:
dispersing the silica microspheres in an aqueous solution containing a salt of the anion, thereby forming a dispersion; and
adding the metal ion containing solution containing metal ions M z+ and M′ y+ to the dispersion, with stirring.

Assignees

• Scg Chemicals Co Ltd

Inventors

• O'Hare Dermot
• Chen Chunping

Classifications

• C09C1/405

  containing combined silica, e.g. mica · CPC title

• B01J27/236 Primary

  Hydroxy carbonates · CPC title

• C01B33/18 Primary

  Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof (preparation of aerogels by dehydrating gels C01B33/158; treatment to enhance the pigmenting or filling properties C09C) · CPC title

• B01J35/397

  Egg shell like · CPC title

• B01J35/53

  with a core-shell structure · CPC title