Small crystal LTL framework type zeolites

Patent metadata

Field	Value
Publication number	US-9573122-B2
Application number	US-201414505308-A
Country	US
Kind code	B2
Filing date	Oct 2, 2014
Priority date	Aug 29, 2014
Publication date	Feb 21, 2017
Grant date	Feb 21, 2017

Abstract

Small crystal LTL framework type zeolites, characterized as polycrystalline aggregates, each of the aggregates comprising a plurality of spherical or cube-like crystallites and wherein each crystallite has an average crystallite size of from 10 to 50 nm, are disclosed. Such zeolites can be prepared by hydrothermal conversion of FAU framework type zeolites at low H 2 O/SiO 2 mole ratios.

First claim

The invention claimed is:

1. A method for preparing an LTL framework type zeolite, characterized as polycrystalline aggregates, each of the aggregates comprising a plurality of spherical or cube-like crystallites and wherein each crystallite has an average crystallite size of from 10 to 50 nm, the method comprising:
(a) preparing a reaction mixture comprising:
(1) a FAU framework type zeolite;
(2) hydroxide ions;
(3) a source of alkali metal (M); and
(4) water;

wherein the reaction mixture comprises, in terms of mole ratios, the following:

SiO 2 /Al 2 O 3
 5 to 60

M/SiO 2
0.15 to 0.50

OH/SiO 2
0.15 to 0.50

H 2 O/SiO 2
 3 to 12

where M is potassium or a mixture of potassium and one or more other alkali metals; and
(b) subjecting the reaction mixture to crystallization conditions sufficient to form crystals of the LTL framework type zeolite.

2. The method of claim 1 , wherein each of the aggregates has a first, a second, and a third dimension, and each of the first, the second, and the third dimensions is from 100 to 300 nm.

3. The method of claim 1 , wherein the aggregates are essentially spherical in shape.

4. The method of claim 1 , wherein at least 80% of the aggregates have an aspect ratio of from 0.7 to 1.

5. The method of claim 1 , wherein the FAU framework type zeolite is zeolite Y.

6. The method of claim 1 , wherein the reaction mixture comprises, in terms of mole ratios, the following:

SiO 2 /Al 2 O 3
10 to 60

M/SiO 2
0.15 to 0.40

OH/SiO 2
0.15 to 0.40

H 2 O/SiO 2
  5 to 10.

7. The method of claim 1 , wherein the hydrothermal conditions include a temperature of from 135° C. to 200° C.

8. The method of claim 1 , wherein the LTL framework type zeolite is prepared in the absence of LTL framework type seed crystals.

9. An LTL framework type zeolite, characterized as polycrystalline aggregates, each of the aggregates comprising a plurality of spherical or cube-like crystallites and wherein each crystallite has an average crystallite size of from 10 to 50 nm.

10. The zeolite of claim 9 , wherein each crystallite has an average crystallite size of from 15 to 35 nm.

11. The zeolite of claim 9 , wherein each of the aggregates has a first, a second, and a third dimension, and each of the first, the second, and the third dimensions is from 100 to 300 nm.

12. The zeolite of claim 9 , wherein each of the aggregates has a first, a second, and a third dimension, and each of the first, the second, and the third dimensions is from 150 to 250 nm.

13. The zeolite of claim 9 , wherein the aggregates are essentially spherical in shape.

14. The zeolite of claim 9 , wherein at least 80% of the aggregates have an aspect ratio of from 0.7 to 1.

15. The zeolite of claim 9 , wherein at least 95% of the aggregates have an aspect ratio of from 0.7 to 1.

Assignees

• Xie Dan
• Zones Stacey Ian
• Saxton Robert James
• Chevron Usa Inc

Inventors

• Xie Dan
• Zones Stacey Ian
• Saxton Robert James

Classifications

• B01J35/77

  Compounds characterised by their crystallite size · CPC title

• B01J35/45

  Nanoparticles · CPC title

• C01P2004/32

  Spheres · CPC title

• C01P2004/62

  Submicrometer sized, i.e. from 0.1-1 micrometer · CPC title

• C01B39/026

  After-treatment · CPC title