Synthesis of DDR framework-type molecular sieves

Patent metadata

Field	Value
Publication number	US-9868642-B2
Application number	US-201514920037-A
Country	US
Kind code	B2
Filing date	Oct 22, 2015
Priority date	Nov 20, 2014
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

A process for synthesizing a DDR framework-type molecular sieve comprises crystallizing a reaction mixture comprising water, a source of silicon, and a structure directing agent, Q, selected from the group consisting of a methyltropinium salt, a 2,6,N,N-tetramethylpiperidinium salt, a 2,N,N-trimethylpiperidinium salt and mixtures thereof, wherein the reaction mixture has a molar ratio of water to silicon from 5 to 80 and a molar ratio of alkali or alkaline earth metal, M, to silicon less than 0.01.

First claim

What is claimed is:

1. A process for synthesizing a DDR framework-type molecular sieve, the process comprising.
(a) forming a reaction mixture capable of forming the molecular sieve, the mixture comprising water, a source of silicon, and a structure directing agent, Q, selected from the group consisting of a methyltropinium salt, a 2,6,N,N-tetramethylpiperidinium salt, a 2,N,N-trimethylpiperidinium salt and mixtures thereof, wherein the reaction mixture has a molar ratio of water to silicon from 5:1 to 80:1 and a molar ratio of alkali or alkaline earth metal, M, to silicon less than 0.01:1;
(b) heating said reaction mixture under conditions effective to produce crystals of the DDR framework-type molecular sieve; and
(c) recovering crystals of the DDR framework-type molecular sieve produced in (b).

2. The process of claim 1 , wherein the molar ratio of water to silicon in the reaction mixture is from 5:1 to 70:1.

3. The process of claim 1 , wherein the molar ratio of water to silicon in the reaction mixture is from 5:1 to 60:1.

4. The process of claim 1 , wherein the molar ratio of water to structure directing agent, Q, in the reaction mixture is from 20:1 to 150:1.

5. The process of claim 1 , wherein the molar ratio of structure directing agent, Q, to silicon in the reaction mixture is at least 0.1:1.

6. The process of claim 1 , wherein the reaction mixture further comprises a source of boron.

7. The process of claim 6 , wherein the reaction mixture has a molar ratio of silica to boron oxide greater than 0.06:1.

8. The process of claim 1 , wherein the reaction mixture has a silica to alumina molar ratio of greater than 150.

9. The process of claim 1 , wherein the source of silicon comprises colloidal silica.

10. The process of claim 1 , wherein the reaction mixture further comprises seeds of a crystalline material comprising a DDR framework-type molecular sieve.

11. The process of claim 1 , wherein the reaction mixture further comprises up to 10 wt %, based on the total weight of silicon as silica in the reaction mixture, of seeds of a crystalline material comprising a DDR framework-type molecular sieve.

12. The process of claim 1 , wherein the reaction mixture further comprises an amine selected from the group consisting of diethanolamine, triethanolamine, ethylenediamine, diethylenetriamine, and mixtures thereof.

13. The process of claim 12 , wherein the molar ratio of amine to structure directing agent in the reaction mixture is from 0.15:1 to 3:1.

14. The process of claim 1 , wherein the heating is conducted at a temperature from 120° C. to 205° C.

Assignees

• Burton Allen W
• Terefenko Eugene
• Exxonmobil Res & Eng Co

Inventors

• Burton Allen W
• Terefenko Eugene

Classifications

• C01B39/12

  the replacing atoms being {at least} boron atoms · CPC title

• C01B37/02

  Crystalline silica-polymorphs, e.g. silicalites {dealuminated aluminosilicate zeolites} · CPC title

• C01B37/007

  Borosilicates · CPC title

• C01B39/48 Primary

  using at least one organic template directing agent · CPC title