Seeded synthesis of aluminosilicate molecular sieves

Patent metadata

Field	Value
Publication number	US-9643852-B2
Application number	US-201314437853-A
Country	US
Kind code	B2
Filing date	Oct 29, 2013
Priority date	Dec 10, 2012
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A process for producing an aluminosilicate molecular sieve comprises crystallizing a reaction mixture comprising water, a source of silica and seeds of a silicoaluminophosphate and/or an aluminophosphate molecular sieve. The resultant aluminosilicate molecular sieve product can advantageously be substantially free of framework phosphorus.

First claim

The invention claimed is:

1. A process for producing an aluminosilicate molecular sieve, wherein the process comprises:
(a) crystallizing a reaction mixture comprising water, a source of silica and seeds of a silicoaluminophosphate and/or an aluminophosphate molecular sieve having a framework type selected from the group consisting of ERI, LEV, AFX, CHA, AEI, and mixtures and intergrowths thereof and being; and
(b) recovering an aluminosilicate molecular sieve substantially free of framework phosphorus.

2. The process of claim 1 , wherein said reaction mixture comprises at least 500 wppm of said seeds.

3. The process of claim 1 , wherein said reaction mixture is substantially free of phosphorus, apart from the phosphorus contained by said seeds.

4. The process of claim 1 , wherein said reaction mixture also comprises a source of fluoride ions.

5. The process of claim 1 , wherein said reaction mixture has a pH no more than 9.

6. The process of claim 1 , wherein said reaction mixture further comprises an organic directing agent effective to direct the synthesis of said aluminosilicate molecular sieve product.

7. The process of claim 1 , wherein said seeds comprise of a silicoaluminophosphate and/or an aluminophosphate molecular sieve have double 6-membered rings as a structural building unit.

8. The process of claim 2 , wherein said reaction mixture comprises from about 1000 wppm to about 50000 wppm of said seeds.

9. The process of claim 2 , wherein said synthesis mixture comprises from about 2000 wppm to about 25000 wppm of said seeds.

10. The process of claim 5 , wherein said reaction mixture has a pH from about 5 to about 9.

Assignees

• Exxonmobil Res & Eng Co

Inventors

• Cao Guang
• Shah Matu J

Classifications

• B01J29/7015

  CHA-type, e.g. Chabazite, LZ-218 · CPC title

• B01J29/85

  Silicoaluminophosphates [SAPO compounds] · CPC title

• C01B39/02

  Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof · CPC title

• C01B39/48

  using at least one organic template directing agent · CPC title

• B01J29/70

  of types characterised by their specific structure not provided for in groups B01J29/08 - B01J29/65 · CPC title