High-silica AFX framework type zeolites

Patent metadata

Field	Value
Publication number	US-9908108-B2
Application number	US-201715498792-A
Country	US
Kind code	B2
Filing date	Apr 27, 2017
Priority date	Jun 7, 2016
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

An AFX framework type zeolite having a SiO 2 /Al 2 O 3 molar ratio of greater than 50 is disclosed. The high-silica AFX framework type zeolite is synthesized from a reaction mixture having high silica and low hydroxide concentrations in the presence of an organic structure directing agent comprising 1,3-bis(1-adamantyl)imidazolium cations.

First claim

The invention claimed is:

1. An AFX framework type zeolite having, it its calcined form, a composition comprising the molar relationship:
Al 2 O 3 :( n )SiO 2
wherein n has a value of greater than 50 to 100.

2. The AFX framework type zeolite of claim 1 , wherein n has a value of greater than 50 to 80.

3. The AFX framework type zeolite of claim 1 , wherein n has a value of 52 to 70.

4. A process for converting a feedstock comprising an organic compound to a conversion product which comprises the step of contacting the feedstock with a catalyst, at organic compound conversion conditions, the catalyst comprising an active form of the AFX framework type zeolite of claim 1 .

5. A process for selectively reducing nitrogen oxides (NO x ), the process comprising contacting a gas stream containing NO x with a catalyst comprising the zeolite of claim 1 .

6. An AFX framework type zeolite having, in it as-synthesized and anhydrous form, a composition, in terms of molar ratios, as follows:

SiO2/Al 2 O 3
>50 to 100 

Q/SiO 2
>0 to 0.1

M/SiO 2
>0 to 0.1

wherein Q comprises 1,3-bis(1-adamantyl)imidazolium cations and M is a metal selected from Groups 1 and 2 of the Periodic Table.

7. The AFX framework type zeolite of claim 6 , wherein the SiO 2 /Al 2 O 3 molar ratio is in a range of greater than 50 to 80.

8. The AFX framework type zeolite of claim 6 , wherein the SiO 2 /Al 2 O 3 molar ratio is in a range of from 52 to 70.

9. A method of synthesizing the AFX framework type zeolite of claim 6 , the method comprising:
(a) providing a reaction mixture comprising:
(1) a source of aluminum comprising a FAU framework type zeolite;
(2) a separate source of silicon;
(3) a source of at least one metal (M) selected from Groups 1 and 2 of the Periodic Table;
(4) a source of 1,3-bis(1-adamantyl)imidazolium cations (Q);
(5) hydroxide ions; and
(6) water; and

(b) subjecting the reaction mixture to crystallization conditions sufficient to form crystals of the AFX framework type zeolite,
wherein the reaction mixture has a composition, in terms of molar ratios, as follows:

SiO 2 /Al 2 O 3
>50 to 100

M/SiO 2
0.05 to 0.25

Q/SiO 2
0.10 to 0.30

OH/SiO 2
0.15 to 0.55

H 2 O/SiO 2
 15 to 60.

10. The method of claim 9 , wherein the crystallization conditions include a temperature of from 125° C. to 200° C.

Assignees

• Chevron Usa Inc

Inventors

• Davis Tracy Margaret

Classifications

• B01D2255/2092

  Aluminium · CPC title

• B01J37/10

  in the presence of water, e.g. steam · CPC title

• C07C1/20

  starting from organic compounds containing only oxygen atoms as heteroatoms · CPC title

• B01D53/9418

  for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas · CPC title

• C07C2529/70

  of types characterised by their specific structure not provided for in groups C07C2529/08 - C07C2529/65 · CPC title