PROCESSES FOR PREPARING A CATALYST

• US 20100009843A1
• Filed: 09/21/2009
• Published: 01/14/2010
• Est. Priority Date: 09/21/2007
• Status: Abandoned Application

• Current Assignee: SunEdison, Inc.
• Original Assignee: SunEdison, Inc.
• Inventors: Revankar, Vithal, Ibrahim, Jameel
• Application Number:
  US12/563,565
• Publication Number:
  US 20100009843A1
• Time in Patent Office: Days
• US Class Current: 502/241
• CPC Class Codes: B01J 21/066 Zirconium or hafnium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 23/8892 Manganese
• CPC Class Codes: B01J 23/94 of catalysts comprising metals, oxides or hydroxides of the iron group metals or copper
• CPC Class Codes: B01J 37/349 making use of flames, plasmas or lasers
• CPC Class Codes: C01B 33/10784 by adsorption
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02P 20/584 Recycling of catalysts

Abstract

Processes for purifying silicon tetrafluoride source gas by subjecting the source gas to one or more purification processes including: contacting the silicon tetrafluoride source gas with an ion exchange resin to remove acidic contaminants, contacting the silicon tetrafluoride source gas with a catalyst to remove carbon monoxide, by removal of carbon dioxide by use of an absorption liquid, and by removal of inert compounds by cryogenic distillation; catalysts suitable for removal of carbon monoxide from silicon tetrafluoride source gas and processes for producing such catalysts.

Claims

1. A process for preparing a catalyst comprising an inert substrate and a catalytic metal oxide being at or near the surface of the inert substrate, the process comprising:

impregnating catalytic metal on the surface of or throughout the bulk of an inert substrate; and

heating the metal-impregnated inert substrate to a temperature of at least about 250°

C. to form a catalytic metal oxide at or near the surface of the inert substrate.

2. A process as set forth in claim 1 wherein the metal-impregnated inert substrate is heated to a temperature of from about 250°

C. to about 1000°

C.

3. A process as set forth in claim 1 wherein the inert substrate comprises an inert metal oxide and is prepared by reacting a first metal halide comprising an inert metal with hydrogen in an oxygen and hydrogen flame to produce a inert substrate powder.

4. A process as set forth in claim 3 wherein the catalytic metal is impregnated throughout the inert substrate by reacting a second metal halide comprising the catalytic metal with hydrogen in an oxygen and hydrogen flame concurrently with the reaction between the first metal halide and hydrogen.

5. A process as set forth in claim 1 wherein the catalytic metal is impregnated onto the inert substrate by precipitating catalytic metal from a metal salt solution onto the inert substrate.

6. A process as set forth in claim 1 wherein the catalytic metal oxide comprises a metal selected from the group consisting of copper, manganese, chromium, cobalt, thallium, molybdenum, silver and mixtures thereof.

7. A process as set forth in claim 6 wherein the catalytic metal oxide comprises a metal selected from the group consisting of copper, manganese or mixtures thereof.

8. A process as set forth in claim 1 wherein the inert substrate is selected from the group consisting of zirconia, alumina silicate, silica, alumina, yttria and mixtures thereof.

9. A process as set forth in claim 8 wherein the inert substrate is selected from the group consisting of zirconia, alumina silicate or mixtures thereof.

10. A process as set forth in claim 1 wherein the inert substrate comprises a metal oxide stabilizer comprising a metal selected from the group consisting of lanthanides, actinides, magnesium, yttrium, calcium, and mixtures thereof.

11. A process as set forth in claim 10 wherein the inert substrate comprises less than about 0.1% by weight stabilizer.

12. A process as set forth in claim 1 wherein the inert substrate comprises less than about 0.1% by weight yttrium oxide as a stabilizer.

13. A process as set forth in claim 1 wherein the catalyst comprises at least about 95% inert substrate by weight, less than about 3% catalytic metal by weight and less than about 0.5% stabilizer by weight.

14. A process as set forth in claim 1 wherein the catalyst comprises from about 0.001% to about 1.0% by weight catalytic metal.

15. A process as set forth in claim 1 wherein the catalyst comprises about 95% to about 99.999% by weight inert substrate.

16. A process as set forth in claim 1 wherein the substrate has a surface area from about 1 m²/g to about 1000 m²/g.

17. A process as set forth in claim 1 wherein the substrate has a bulk porosity of from about 30% to about 80%.