Supported metal catalyst, preparation and applications for directly making hydrogen peroxide

• US 6,958,138 B1
• Filed: 06/07/2000
• Issued: 10/25/2005
• Est. Priority Date: 07/16/1999
• Status: Expired due to Fees

• Current Assignee: Arkema France (Arkema)
• Original Assignee: Arkema
• Inventors: Devic, Michel
• Primary Examiner(s): Langel, Wayne A.
• Application Number:
  US10/018,868
• Time in Patent Office: 1,966 Days
• Field of Search: 423/584, 423/588, 502/325, 502/339, 502/302, 502/344
• US Class Current: 423/584
• CPC Class Codes: B01J 19/1881 externally, i.e. the mixture leaving the vessel and subsequently re-entering it
• CPC Class Codes: B01J 2208/00176 outside the reactor
• CPC Class Codes: B01J 2208/00212 Plates; Jackets; Cylinders
• CPC Class Codes: B01J 2219/185 vertical
• CPC Class Codes: B01J 23/38 of noble metals
• CPC Class Codes: B01J 23/40 of the platinum group metals
• CPC Class Codes: B01J 27/13 Platinum group metals
• CPC Class Codes: B01J 35/60 characterised by their surface properties or porosity
• CPC Class Codes: B01J 35/615 100-500 m2/g
• CPC Class Codes: B01J 35/635 0.5-1.0 ml/g
• CPC Class Codes: B01J 37/0201 Impregnation
• CPC Class Codes: B01J 37/22 Halogenating
• CPC Class Codes: B01J 8/006 by filtration
• CPC Class Codes: B01J 8/222 in the presence of a rotating device only
• CPC Class Codes: B01J 8/228 externally, i.e. the particles leaving the vessel and subsequently re-entering it
• CPC Class Codes: C01B 15/029 Preparation from hydrogen and oxygen

Abstract

The invention concerns a supported metal catalyst based on at least one metal selected in the group M consisting of palladium, platinum, ruthenium, rhodium, iridium, holmium, osmium and gold, used for directly making hydrogen peroxide from hydrogen and oxygen. The invention also concerns a method for making said catalyst comprising successively an impregnating step with a solution based on one or several salt(s) of at least one metal of group M on a support, and a reduction step characterised in that at the end of the reduction step, the catalyst is treated with an aqueous acid solution comprising bromine and bromide ions. The catalyst is characterised by metal or crystallised metal aggregates with size ranging between 0.1 and 20 microns and preferably between 0.1 and 10 microns. The supported bimetal catalyst is preferred, for example Pd—Pt, Au—Pt, Pd—Ho and Pd—Au.

Claims

1. A process for preparing a supported metal catalyst, comprising:

(a) impregnating a support with a solution of a salt of a metal selected from the group consisting of palladium, platinum, ruthenium, rhodium, iridium, osmium, holmium and gold;

(b) subjecting the impregnated support to a reduction process; and

(c) treating the impregnated support obtained in step (b) with an aqueous acid solution containing bromine and bromide ion.

2. The process of claim 1, wherein the concentration of bromide ions in the aqueous acid solution is between about 20 mg/l and about 200 mg/l.

3. The process of claim 1, wherein the concentration of bromide ions in the aqueous acid solution is between about 20 mg/l and about 100 mg/l.

4. The process of claim 1, wherein the concentration of bromine in the aqueous acid solution is between about 2 mg/l and about 20 mg/l.

5. The process of claim 1, wherein the concentration of bromine in the aqueous acid solution is between about 2 mg/l and about 10 mg/l.

6. The process of claim 1, wherein the pH of the aqueous acid solution is between about 1 and about 3.

7. The process of claim 1, wherein step(c) is conducted at a temperature between about 10°

C. and about 80°

C.

8. The process of claim 7, wherein the temperature is between about 40°

C. and about 60°

C.

9. The process of claim 1, wherein, the impregnated support obtained in step (c) is separated from the aqueous acid solution and dried at a temperature between about 100°

C. and about 140°

C.

10. The process of claim 9, wherein, a slurry is obtained in step (a), which is filtered, drained and then dried before step (b).

11. The process of claim 10, wherein the drying is carried out under conditions conducive to slow crystallization.

12. The process of claim 1, wherein the metal-salt solution comprises two kinds of metal salts so that a supported bimetallic catalyst is obtained.

13. The process of claim 12, wherein the two kinds of metal salts are a majority metal salt and a minority metal salt, and the bimetallic catalyst comprises about 0.001% to about 0.1% by weight minority metal based on the weight of the bimetallic catalyst.

14. The process of claim 12, wherein the metal-salt solution contains salts of palladium and gold.

15. The process of claim 12, wherein the minority metal is platinum.

16. The process of claim 1, wherein the support is a silica having a BET specific surface area.

17. The process of claim 15, wherein the BET specific surface is greater than 200 m²/g.

18. A supported metal catalyst, which comprises a support and a metal selected from the group consisting of palladium, platinum, ruthenium, rhodium, iridium, osmium, holmium and gold, wherein the metal is disposed on the support in a form of cluster of crystals, and wherein the size of the cluster is between about 0.1 μ

m and about 20 μ

m.

19. The catalyst of claim 18, wherein the size of the cluster is between about 0.1 μ

m and about 10 μ

m.

20. The catalyst of claim 18, wherein the supported metal catalyst contains about 0.1% to about 10% by weight based on the weight of the catalyst.

21. The catalyst of claim 18, which is a supported bimetallic catalyst comprising two kinds of metals.

22. A The catalyst of claim 21, wherein the two kinds of metals are a majority metal and a minority metal, and said catalyst contains about 0.001% to about 0.1% minority metal by weight based on the weight of the catalyst.

23. The catalyst of claim 21, wherein the metals are palladium and gold.

24. The catalyst of claim 21, wherein the minority metal is platinum.

25. The catalyst of claim 18, wherein the support is a silica having a BET specific surface area.

26. The catalyst of claim 25, wherein the BET specific surface is greater than 200 m²/g.

27. A process for manufacturing hydrogen peroxide, wherein conducting a direct reaction between hydrogen and oxygen using the supported metal catalyst of claim 18.