Carbonylation process for the production of methyl acetate
A process for the production of methyl acetate by reacting dimethyl ether with carbon monoxide into a carbonylation reactor containing a mordenite catalyst in the presence of added methyl acetate and/or acetic acid.
1. A process for the production of methyl acetate, which process comprises carbonylating dimethyl ether with carbon monoxide in one or more carbonylation reaction zones in the presence of a mordenite catalyst to produce methyl acetate product wherein at least one of acetic acid and additional methyl acetate is added to at least one of said reaction zone(s).
2. A process according to claim 1 wherein the process is carried out in the presence of hydrogen.
3. A process according to claim 1 wherein the molar ratio of the additional methyl acetate to dimethyl ether is in the range 1:100 to 5:1.
4. A process according to claim 3 wherein the molar ratio of the additional methyl acetate to dimethyl ether is in the range 1:10 to 3:1.
5. A process according to claim 1 wherein the additional methyl acetate is added to a reaction zone in an amount in the range 0.05 mol % to 5 mol % based on the total gaseous feeds, including recycles.
6. A process according to claim 5 wherein the additional methyl acetate is added to a reaction zone in an amount in the range 0.5 mol % to 5 mol % based on the total gaseous feeds, including recycles.
7. A process according to claim 1 wherein the additional methyl acetate is added to a reaction zone as fresh and/or recycle methyl acetate and/or as product methyl acetate.
8. A process according to claim 1 wherein the additional methyl acetate is introduced to the reaction zone on start-up of the carbonylation process.
9. A process according to claim 1 wherein acetic acid is added to a reaction zone in an amount in the range (greater than 0) mol % to 1 mol % based on the total gaseous feeds, including recycles.
10. A process according to claim 9 wherein acetic acid is added to a reaction zone in an amount in the range 0.1 mol % to 0.8 mol % based on the total gaseous feeds (including recycles).
11. A process according to claim 1 wherein the mordenite catalyst is selected from H-mordenite, a copper mordenite and a silver mordenite.
12. A process according to claim 1 wherein the process is carried out in 2 to 30 reaction zones connected in series.
13. A process according to claim 12 wherein dimethyl ether is introduced into a reaction zone as fresh and/or recycle dimethyl ether.
14. A process according to claim 13 wherein dimethyl ether is introduced to a reaction zone as fresh dimethyl ether together with at least one of fresh and/or recycle methyl acetate and acetic acid.
15. A process according to claim 1 wherein methyl acetate product is hydrolysed to acetic acid.
16. A process according to claim 1 wherein the carbon monoxide is fed into a reaction zone as a mixture with hydrogen.
17. A process according to claim 16 wherein the carbon monoxide and hydrogen are present in the mixture in a molar ratio of 1:3 to 15:1.