Pentasil-type zeolite and production method therefor

Patent metadata

Field	Value
Publication number	US-11752487-B2
Application number	US-201917287333-A
Country	US
Kind code	B2
Filing date	Oct 18, 2019
Priority date	Oct 25, 2018
Publication date	Sep 12, 2023
Grant date	Sep 12, 2023

Abstract

Provided are a pentasil-type zeolite that is less likely to adsorb water compared to conventional zeolites and has excellent strength when used as a molded body, and a method for producing the pentasil-type zeolite.
A pentasil-type zeolite having a water adsorption amount of 4.0 g/100 g-zeolite or less under the conditions of 25° C. and a relative humidity of 90% and having a major axis diameter of primary particles of from 0.2 μm to 4.0 μm, and a method for producing the pentasil-type zeolite.

First claim

The invention claimed is:

1. A pentasil-type zeolite having a water adsorption amount of 4.0 g/100 g-zeolite or less under the conditions of 25° C. and a relative humidity of 90% and having a major axis diameter of primary particles of from 0.2 μm to 4.0 μm.

2. The pentasil-type zeolite according to claim 1 , wherein the pentasil-type zeolite has an aspect ratio of primary particles of from 1.0 to 3.0.

3. The pentasil-type zeolite according to claim 1 , wherein the pentasil-type zeolite has a ratio SiO 2 /Al 2 O 3 (molar ratio) of 200 or higher.

4. The pentasil-type zeolite according to claim 1 , wherein the pentasil-type zeolite has a BET specific surface area of 300 m 2 /g or larger.

5. The pentasil-type zeolite according to claim 1 , wherein the pentasil-type zeolite has a content of Na 2 O of 1.00 percent by weight or less.

6. A method for producing the pentasil-type zeolite according to claim 1 , comprising:
crystallizing a mixture including a silicon source, an amine as a structure-directing agent, and an alkali source, the mixture including no fluorine source, to form a zeolite;
bringing the zeolite into contact with an alkali solution at pH 10 to 14; and
calcining the zeolite at a temperature of 500° C. to 1000° C. under a flow of water vapor.

7. The method for producing the pentasil-type zeolite according to claim 6 , wherein the amine is n-propylamine, dipropylamine, or tripropylamine.

8. The method for producing the pentasil-type zeolite according to claim 6 , wherein the crystallization temperature is 160° C. or lower.

9. The method for producing the pentasil-type zeolite according to claim 6 , wherein the mixture has the following molar composition:

Structure-directing agent/SiO 2
from 0.04 to 0.5

OH − /SiO 2
 from 0.08 to 0.2.

Assignees

• Tosoh Corp

Inventors

• Yamada Hidenori
• Okaniwa Hiroshi
• Yoshida Satoshi

Classifications

• B01J35/40

  characterised by dimensions, e.g. grain size (in a colloidal state B01J35/23; crystallite size B01J35/77) · CPC title

• B01J29/40 Primary

  of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively · CPC title

• B01J20/186 Primary

  Chemical treatments in view of modifying the properties of the sieve, e.g. increasing the stability or the activity, also decreasing the activity · CPC title

• B01J37/30

  Ion-exchange · CPC title

• B01J37/082

  Decomposition and pyrolysis · CPC title