Method for the production of a titanium-containing zeolite

• US 20030035771A1
• Filed: 08/29/2002
• Published: 02/20/2003
• Est. Priority Date: 03/02/2000
• Status: Active Grant

• Current Assignee: Evonik Degussa GmbH
• Original Assignee: Degussa AG (Rag-Stiftung)
• Inventors: Hasenzahl, Steffen
• Granted Patent: US 6,896,859 B2
• Time in Patent Office: Days
• US Class Current: 423/713
• CPC Class Codes: B01J 29/89 Silicates, aluminosilicates or borosilicates of titanium, zirconium or hafnium B01J29/005 takes precedence
• CPC Class Codes: C01B 37/005 Silicates, i.e. so-called metallosilicalites or metallozeosilites
• CPC Class Codes: C07D 301/12 with hydrogen peroxide or inorganic peroxides or peracids
• CPC Class Codes: Y10S 423/22 MFI, e.g. ZSM-5. silicalite, LZ-241

Abstract

The present invention concerns a method for the production of a titanium-containing zeolite by: (a) combining a hydrolyzable silicon compound and a hydrolyzable titanium compound; (b) adding a basic quaternary ammonium compound in an aqueous medium to the mixture from (a) and hydrolysing the reaction mixture at a temperature in the range from 0° C. to 100° C. to form a synthesis sol; then (c) heating the synthesis sol to a temperature in the range from 150° C. to 190° C.; and (d) crystallizing the synthesis sol at this temperature, characterized in that the heating-up time in step (c) is less than 240 min.

Claims

1. Method for the production of a titanium-containing zeolite by

a) combining a hydrolyzable silicon compound and a hydrolyzable titanium compound,

b) adding a basic quaternary ammonium compound in an aqueous medium to the mixture from a) and hydrolysing the reaction mixture at a temperature in the range from 0°

C. to 100°

C. to form a synthesis sol, then

c) heating the synthesis sol to a temperature in the range from 150°

C. to 190°

C. and

d) crystallizing the synthesis sol at this temperature, characterized in that

the heating-up time in step c) is less than 240 min.

2. Method according to claim 1,

characterized in that

the heating-up time is 60 to 180 minutes, preferably 80 to 120 minutes.

3. Method according to any of the preceding claims,

characterized in that

the hydrolysable silicon compound is a tetraalkyl orthosilicate, preferably tetraethyl orthosilicate, and the hydrolysable titanium compound is a tetraalkyl orthotitanate, preferably tetraethyl orthotitanate.

4. Method according to claim 3,

characterized in that

after step b) and before step c) the synthesis sol is heated to a temperature of 75°

C. to 100°

C. for a period of 120 to 200 minutes and the resulting alcohol is distilled off in order to support the hydrolysis of the hydrolysable titanium and silicon compounds and optionally the volume of alcohol removed by distillation is replaced at least in part by the addition of water to the synthesis sol.

5. Method according to any of the preceding claims,

whereby the quaternary ammonium compound is a tetraalkyl ammonium hydroxide, preferably tetra-n-propyl ammonium hydroxide.

6. Method according to any of the preceding claims,

whereby the titanium-containing zeolite is separated off, dried and calcined.

7. Method for the epoxidation of olefins by reacting olefins with aqueous hydrogen peroxide in a solvent miscible with water in the presence of a titanium-containing zeolite as catalyst that is obtainable by the method according to claim 6.

8. Use of a titanium-containing zeolite obtainable by the method according to claim 6 as catalyst for the epoxidation of olefins with hydrogen peroxide.