Metal-loaded zeolite catalysts for the halogen-free conversion of dimethyl ether to methyl acetate
A catalyst for the carbonylation of dimethyl ether to methyl acetate. The catalyst comprises a zeolite, such as a mordenite zeolite, at least one Group IB metal, such as copper, and/or at least one Group VIII metal, such as iron, and at least one Group IIB metal, such as zinc. Such a catalyst with combined metals provides enhanced catalytic activity, improved stability, and improved selectivity to methyl acetate, and does not require a halogen promoter, as compared to a metal-free or copper only zeolite.
1. A method of treating a catalyst comprising:
(i) a zeolite selected from the group consisting of mordenite zeolites, zeolite Beta, ferrierite, zeolite Y, ZSM-5, ZSM-23, ZSM-35, and ZSM-57; (ii) zinc; and (iii) copper, said method consisting essentially of contacting said catalyst with a gas comprising oxygen and an inert gas.
2. The method of claim 1 wherein said zeolite is a mordenite zeolite.
3. The method of claim 1 wherein said zeolite is ferrierite.
4. The method of claim 1 wherein said zeolite is ZSM-23.
5. The method of claim 1 wherein said copper and said zinc are present in said catalyst at a molar ratio of said copper to said zinc of about 0.25.
6. The method of claim 1 wherein said catalyst is free of halogens and halogen-containing compounds.
7. The method of claim 1 , wherein said catalyst further comprises:
(iv) palladium.
8. The method of claim 2 wherein said mordenite zeolite has a Si/AI ratio of from about 5:1 to about 90:1.
9. The method of claim 8 wherein said mordenite zeolite has a Si/AI ratio of from about 5:1 to about 50:1.
10. The method of claim 1 wherein said inert gas is helium.
11. The method of claim 1 wherein said catalyst is heated to a temperature of from about 20° C. to about 800° C.
12. The method of claim 11 wherein said catalyst is heated to a temperature of from about 20° C. to about 550° C.
13. The method of claim 1 wherein said oxygen is present in said gas in an amount of from about 1 vol. % to about 20 vol. %.
14. The method of claim 13 wherein said oxygen is present in said gas in an amount of from about 5 vol. % to about 15 vol. %.
15. The method of claim 14 wherein said oxygen is present in said gas in an amount of about 10 vol. %.
16. The method of claim 10 wherein said helium is present in said gas in an amount of from about 80 vol. % to about 99 vol. %.
17. The method of claim 16 wherein said helium is present in said gas in an amount of from about 85 vol. % to about 95 vol. %.
18. The method of claim 17 wherein said helium is present in said gas in an amount of about 90 wt. %.