Zeolites with mww framework formed of silicon and zinc or iron, and related methods

Patent metadata

Field	Value
Publication number	US-2016376159-A1
Application number	US-201515125135-A
Country	US
Kind code	A1
Filing date	Mar 10, 2015
Priority date	Mar 10, 2014
Publication date	Dec 29, 2016
Grant date	—

Abstract

A Zn—Si or Fe—Si zeolite having an MWW framework may be formed by treating a gel solution with a hydrothermal treatment. The gel solution includes water, a silicon source, a zinc or iron source, and an MWW-templating agent. The hydrothermal treatment may include dissolving the source materials in the gel solution, and heating the gel solution with the dissolved sources to induce hydrothermal crystallization in the gel solution. The zeolite can be substantially free of aluminum, and can be used in a catalyst, or in a separation or purification device.

First claim

1 . A method comprising:
treating a gel solution by a hydrothermal treatment, to form a Zn—Si or Fe—Si zeolite having an MWW framework, wherein said gel solution comprises water, a silicon source, a zinc or iron source, and an MWW-templating agent, wherein a molar ratio of said silicon source to said zinc or iron source in said gel solution is from 7:1 to 20:1; or wherein said gel solution comprises about 20 wt % of said silicon source and about 3 to about 4 wt % of said zinc or iron source, based on a total weight of said gel solution, and wherein said MWW framework is substantially free of aluminum.

2 . The method of claim 1 , wherein said gel solution is maintained at a first temperature to dissolve said silicon source and said zinc or iron source in said gel solution; and said hydrothermal treatment comprises heating the gel solution with the dissolved silicon source and zinc or iron source at a second temperature above the first temperature, to induce hydrothermal crystallization in said gel solution, thus forming a crystalline Zn—Si or Fe—Si zeolite having said MWW framework.

3 . The method of claim 2 , wherein said first temperature is in the range from room temperature to about 70° C.; and said second temperature is in the range from about 140° C. to about 160° C.

4 . The method of claim 2 , wherein said gel solution is heated at said first temperature for a period of up to about 24 hours, and at said second temperature for a period of 1 to 6 weeks.

5 . The method of claim 1 , wherein said MWW-templating agent comprises a hexamethyleneimine.

6 . The method of claim 1 , wherein said silicon source is selected from colloidal silica, fumed silica, silicon oxides, silicates, and mixtures thereof; and wherein said zinc or iron source is selected from zinc nitrates, zinc halides, zinc sulfates, zinc carbonates, zinc alkoxides, and mixtures thereof.

7 . The method of claim 1 , wherein said gel solution comprises a base.

8 . The method of claim 7 , wherein said base comprises sodium hydroxide.

9 . The method of claim 1 , wherein said gel solution has a pH value of above 7 before said hydrothermal treatment.

10 . The method of claim 1 , wherein said gel solution comprises seeds having an MWW framework.

11 . The method of claim 1 , wherein said Zn—Si or Fe—Si zeolite is a Zn—Si zeolite, and said zinc or iron source is a zinc source.

12 . A zeolite prepared according to a method comprising:
treating a gel solution by a hydrothermal treatment, to form a Zn—Si or Fe—Si zeolite having an MWW framework, wherein said gel solution comprises water, a silicon source, a zinc or iron source, and an MWW-templating agent, wherein a molar ratio of said silicon source to said zinc or iron source in said gel solution is from 7:1 to 20:1; or wherein said gel solution comprises about 20 wt % of said silicon source and about 3 to about 4 wt % of said zinc or iron source, based on a total weight of said gel solution, and wherein said MWW framework is substantially free of aluminum.

13 . A Zn—Si zeolite having an MWW framework substantially free of aluminum.

14 . The zeolite of claim 12 , characterized by an x-ray diffraction pattern comprising the following peaks:

d-value (Å)
2-θ (degree)
Relative Intensity

12.4
7.2
High

11.1
8.0
High

8.85
10.0
Medium

6.17
14.3
Medium

3.91
22.7
Medium

3.42
26.1
Medium

15 . A Fe—Si zeolite having an MWW framework substantially free of aluminum.

16 . The zeolite of claim 12 , characterized by an x-ray diffraction pattern comprising the following peaks:

d-value (Å)
2-θ (degree)
Relative Intensity

11.2
7.9
High

10.1
8.8
Medium

6.87
12.9
Low

5.85
15.1
Low

4.00
22.2
Medium

3.35
26.6
Low

17 . A catalyst comprising a zeolite prepared according to a method comprising:
treating a gel solution by a hydrothermal treatment, to form a Zn—Si or Fe—Si zeolite having an MWW framework, wherein said gel solution comprises water, a silicon source, a zinc or iron source, and an MWW-templating agent, wherein a molar ratio of said silicon source to said zinc or iron source in said gel solution is from 7:1 to 20:1; or wherein said gel solution comprises about 20 wt % of said silicon source and about 3 to about 4 wt % of said zinc or iron source, based on a total weight of said gel solution, and wherein said MWW framework is substantially free of aluminum.

18 . The catalyst of claim 17 for use in catalyzing an activation, oxidehydrogenation, or dehydrogenation reaction.

19 . A separation or purification device comprising a zeolite prepared according to a method comprising:
treating a gel solution by a hydrothermal treatment, to form a Zn—Si or Fe—Si zeolite havin

Assignees

• Agency Science Tech & Res

Inventors

• Liu Yan
• Borgna Armando

Classifications

• C01P2002/82

  by IR- or Raman-data · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title

• C07C45/002

  by dehydrogenation · CPC title

• C01B39/48 Primary

  using at least one organic template directing agent · CPC title

• C07C5/48

  with oxygen as an acceptor · CPC title