Process for preparing crystalline microporous and mesoporous metal silicates, products obtainable by said process and their use

• US 6,710,193 B2
• Filed: 08/17/2001
• Issued: 03/23/2004
• Est. Priority Date: 06/19/1996
• Status: Expired due to Term

• Current Assignee: Evonik Degussa GmbH
• Original Assignee: Degussa AG (Rag-Stiftung)
• Inventors: Scholz, Mario, Mangold, Helmut, Hasenzahl, Steffen, Thiele, Georg, Roland, Eckehart
• Primary Examiner(s): Trinh, Ba K.
• Application Number:
  US09/931,025
• Publication Number:
  US 20010055562A1
• Time in Patent Office: 949 Days
• Field of Search: 549/529, 549/531
• US Class Current: 549/529
• CPC Class Codes: B01J 29/04 having base-exchange properties, e.g. crystalline zeolites B01J29/005 takes precedence
• CPC Class Codes: B01J 29/86 Borosilicates; Aluminoborosilicates B01J29/005 takes precedence
• CPC Class Codes: B01J 29/89 Silicates, aluminosilicates or borosilicates of titanium, zirconium or hafnium B01J29/005 takes precedence
• CPC Class Codes: C01B 37/00 Compounds having molecular sieve properties but not having base-exchange properties
• CPC Class Codes: C01B 37/005 Silicates, i.e. so-called metallosilicalites or metallozeosilites
• CPC Class Codes: C01B 39/065 Galloaluminosilicates; Group IVB- metalloaluminosilicates; Ferroaluminosilicates
• CPC Class Codes: C01B 39/12 the replacing atoms being at least boron atoms
• 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
• CPC Class Codes: Y10S 423/27 Beta, e.g. NU-2
• CPC Class Codes: Y10S 423/29 MEL, e.g. ZSM-11

Abstract

Microporous and mesoporous metal silicates are prepared by the hydrothermal reaction of a silicon and metal source in the presence of a template. The choice of raw materials influences the purity and hence the catalytic activity of the products. A pyrogenic mixed oxide is used as the silicon and metal source. Prepared products have the composition (SiO₂)_1-x(A_mO_n)_x, where A is Ti, Al, B, V or Zr and x is 0.005 to 0.1. Shaped objects of the microporous and mesoporous metal silicates are obtained directly by using a shaped object of the pyrogenic mixed oxide. The products obtained are used as oxidation catalysts.

Claims

1. A method for the catalytic oxidation of a substance comprising:

oxidizing said substance, in the presence of an Al-free metal silicate catalyst, with hydrogen peroxide or an organic hydro-peroxide;

wherein the catalyst is selected from the group consisting of microporous and mesoporous metal silicates, obtained by the hydrothermal reaction of a silicon and metal source in the presence of a template,

wherein a pyrogenic metal-silicon mixed oxide is the silicon and metal source,

wherein the microporous and mesoporous metal silicates are represented by the composition (SiO₂)_1-x(TiO₂)_x in which x is a number from 0.0001 to 0.25.

2. The method as claimed in claim 1, wherein said substance is an olefin.

3. The method according to claim 1, wherein the substance is propene and oxidized with hydrogen peroxide to give the corresponding epoxide.

5. The method according to claim 1, wherein the catalyst is binder-free.

4. A method for the catalytic epoxidation of a propene, with hydrogen peroxide as the oxidant, comprising carrying out the epoxidation in the presence of a catalyst which is a crystalline microporous titanium silicate of the composition (SiO₂)_1-x(TiO₂)_x in which x is a number from 0.0001 to 0.2,

wherein the catalyst has been obtained by reacting a pyrogenic silicon-titanium mixed oxide with a tetraalkylammonium hydroxide template in a hydrothermal reaction at a temperature from 100 to 220°

C.

6. The method according to claim 4, wherein the pyrogenic silicon-titanium mixed oxide is shaped prior to the hydrothermal reaction and the catalyst is obtained with essentially the same shape as the pyrogenic silicon-titanium mixed oxide.

7. The method according to claim 6, wherein the progenic silicon-titanium mixed oxide is shaped by a spray-drying process.