Process for the preparation of doped pentasil-type zeolites using a doped reactant

• US 6,969,692 B2
• Filed: 08/25/2003
• Issued: 11/29/2005
• Est. Priority Date: 08/28/2002
• Status: Active Grant

• Current Assignee: Albemarle Netherlands BV (Albemarle Corporation)
• Original Assignee: Albemarle Netherlands BV (Albemarle Corporation)
• Inventors: Brady, Mike, Stamires, Dennis, O'Connor, Paul, Laheij, Erik Jeroen
• Primary Examiner(s): JOHNSON, CHRISTINA ANN
• Application Number:
  US10/647,632
• Publication Number:
  US 20040121900A1
• Time in Patent Office: 827 Days
• Field of Search: 502/60, 502/64, 502/66, 502/71, 502/77, 423/700, 423/710, 423/711
• US Class Current: 502/66
• CPC Class Codes: B01J 29/04 having base-exchange properties, e.g. crystalline zeolites B01J29/005 takes precedence
• CPC Class Codes: B01J 29/405 containing rare earth elements, titanium, zirconium, hafnium, zinc, cadmium, mercury, gallium, indium, thallium, tin or lead
• CPC Class Codes: C01B 39/06 Preparation of isomorphous zeolites characterised by measures to replace the aluminium or silicon atoms in the lattice framework by atoms of other elements , i.e. by direct or secondary synthesis
• CPC Class Codes: C01B 39/065 Galloaluminosilicates; Group IVB- metalloaluminosilicates; Ferroaluminosilicates

Abstract

A process for the preparation of a metal-doped pentasil-type zeolite comprising the steps of:

• a) preparing an aqueous precursor mixture comprising a silicon source and an aluminum source, at least one of these sources being doped with a rare earth metal or a transition metal of Groups Vb–VIIIb, Ib, or IIb of the Periodic System, and
• b) thermally treating the precursor mixture to form a metal-doped pentasil-type zeolite.

With this process, metal-doped pentasil-type zeolites can be prepared while the risk of precipitation of the dopant as a separate phase is minimized.

Claims

1. A process for the preparation of a metal-doped pentasil-type zeolite, which process comprises the steps of:

a) preparing an aqueous precursor mixture comprising a silicon source and an aluminum source, at least one of these sources being doped with a rare earth metal or a transition metal of Groups Vb–

VIIIb, Ib, or IIb of the Periodic System, and

b) thermally treating the precursor mixture to form a metal-doped pentasil-type zeolite.

2. The process of claim 1 wherein the doped pentasil-type zeolite is doped ZSM-5.

3. The process of claim 1 wherein a metal-doped silicon source is used.

4. The process of claim 3 wherein the metal-doped silicon source is selected from the group consisting of metal-doped sodium (meta)silicate or water glass, metal-doped stabilised silica sols, metal-doped silica gels, metal-doped polysilicic acid, metal-doped tetra ethylortho silicate, metal-doped fumed silicas, metal-doped precipitated silicas, and mixtures thereof.

5. The process of claim 1 wherein a metal-doped aluminum source is used.

6. The process of claim 5 wherein the aluminum source is selected from the group consisting of metal-doped aluminum trihydrate (Al(OH)₃), metal-doped thermally treated aluminum trihydrate, metal-doped (pseudo)boehmite, metal-doped aluminum chlorohydrol, metal-doped aluminum nitrohydrol, and mixtures thereof.

7. The process of claim 1 wherein the aluminum source and/or the silicon source is doped with a metal selected from the group consisting of Ce, La, Mn, Fe, Cu, Ni, Zn, Mo, W, V, Pt, and Pd.

8. The process of claim 1 wherein a shaping step is performed between steps a) and b).