Method for the production of a titanium-containing zeolite

• US 20030103894A1
• Filed: 09/03/2002
• Published: 06/05/2003
• Est. Priority Date: 03/02/2000
• Status: Active Grant

• Current Assignee: Evonik Degussa GmbH
• Original Assignee: Degussa AG (Rag-Stiftung)
• Inventors: Heyne, Klaus, Kneitel, Dieter, Hasenzahl, Steffon
• Granted Patent: US 6,841,144 B2
• Time in Patent Office: Days
• US Class Current: 423/705
• 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

Abstract

The present invention concerns a method for the production of a titanium-containing zeolite whereby a synthesis gel is formed by combining and hydrolysing a hydrolysable silicon compound, a hydrolysable titanium compound and a basic quaternary ammonium compound in an aqueous medium, in quantities such that relative to the starting compounds the molar ratio of Si/Ti is greater than or equal to 30 and that of N/Si is 0.12 to less than 0.20, and the synthesis gel is then crystallised at a temperature of 150° C. to 220 ° C. for a period of less than 3 days, and a titanium-containing zeolite obtainable by this method.

Claims

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

whereby a synthesis gel is formed by combining and hydrolysing a hydrolysable silicon compound, a hydrolysable titanium compound and a basic quaternary ammonium compound in an aqueous medium, in quantities such that relative to the starting compounds the molar ratio of Si/Ti is greater than or equal to 30 and that of N/Si is 0.12 to less than 0.20, and the synthesis gel is then crystallised at a temperature of 150°

C. to 220°

C. for a period of less than 3 days.

2. Method according to claim 1,

whereby the molar ratio of N/Si is 0.12 to less than 0.17.

3. Method according to any of the preceding claims,

whereby the molar ratio of H₂O/Si relative to the starting compounds is 10 to 20.

4. Method according to claim 3,

whereby the molar ratio of H₂O/Si is 12 to 17.

5. Method according to any of the preceding claims,

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

6. Method according to claim 5,

whereby the hydrolysis of the hydrolysable titanium and silicon compounds is supported by distilling off the resulting alcohols and optionally the volume of alcohol removed by distillation is replaced at least in part by the addition of water to the reaction mixture.

7. Method according to any of the preceding claims,

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

8. Method according to any of the preceding claims,

whereby the pH value of the crystal suspension from the crystallisation stage is adjusted to a value of 7 to 10, preferably 7 to 8.5.

9. Method according to any of the preceding claims,

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

10. Titanium-containing zeolite obtainable by a method according to any of the preceding claims with a primary crystallite size of 0.2 to 2.0 μ

m.

11. 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 according to claim 10 or that is obtainable by the method according to claim 9.

12. Use of a titanium-containing zeolite obtainable by the method according to claim 10 or that is obtainable by the method according to claim 9 as catalyst for the epoxidation of olefins with hydrogen peroxide.