Process for carbonylating dimethyl ether
A process for the production of methyl acetate by carbonylating dimethyl ether with carbon monoxide at a temperature of 250 to 350° C. in the presence of a zeolite catalyst and hydrogen such that the molar ratio of hydrogen to carbon monoxide is at least 1, and one or more compounds containing a hydroxyl functional group and in the absence of any added methyl acetate.
1. A process for the production of methyl acetate by carbonylation of dimethyl ether which process comprises contacting in a reactor dimethyl ether with carbon monoxide in the presence of a zeolite catalyst, hydrogen, and at least one compound containing a hydroxyl functional group at a temperature of from 250 to 350° C. and at a molar ratio of hydrogen to carbon monoxide of at least 1,
wherein the process comprises introducing into the reactor the at least one compound containing a hydroxyl functional group, and the process is carried out in the absence of added methyl acetate;
wherein the at least one compound containing a hydroxyl functional group is one or more hydroxyl compound(s) selected from water, C 1 -C 4 aliphatic alcohols, and C 1 -C 4 aliphatic carboxylic acids; and
wherein the zeolite is a templated zeolite.
2. A process according to claim 1 wherein the hydroxyl compound(s) is introduced into the reactor in a total amount of up to 1 mol % based on a total gaseous feed to the process including the hydroxyl compound(s), dimethyl ether, carbon monoxide, and hydrogen.
3. A process according to claim 2 wherein the total amount of hydroxyl compound(s) is from 0.01 to 0.5 mol % based on the total gaseous feed to the process.
4. A process according to claim 1 , wherein the one or more hydroxyl compound(s) is selected from C 1 -C 4 aliphatic alcohols and C 1 -C 4 aliphatic carboxylic acids.
5. A process according to claim 4 wherein the hydroxyl compound is a C 1 -C 4 aliphatic alcohol.
6. A process according to claim 4 wherein the hydroxyl compound is a C 1 -C 4 aliphatic carboxylic acid.
7. A process according to claim 1 wherein the hydroxyl compound(s) is selected from one or more of acetic acid, methanol and water.
8. A process according to claim 1 , wherein the molar ratio of hydrogen to carbon monoxide is in the range 1.5 to 4:1.
9. A process according to claim 1 , wherein the catalyst is a zeolite having at least one channel which is defined by an 8-membered ring.
10. A process according to claim 9 wherein the zeolite has a framework type selected from the group consisting of MOR, FER, OFF, CHA, GME, MFS, EON and ETR.
11. A process according to claim 10 wherein the zeolite has the framework type MOR and is mordenite.
12. A process according to claim 1 , wherein the process is carried out at a temperature of from 275 to 325° C.
13. A process according to claim 1 , wherein methyl acetate product is hydrolysed to acetic acid.
14. A method of maintaining or reducing the deactivation rate of a catalyst in a process for the production of methyl acetate by carbonylation of dimethyl ether which process comprises contacting in a reactor dimethyl ether with carbon monoxide in the presence of a zeolite catalyst, hydrogen, and at least one compound containing a hydroxyl functional group at a temperature of from 250 to 350° C. and at a molar ratio of hydrogen to carbon monoxide of at least 1,
wherein the process comprises introducing into the reactor the at least one compound containing a hydroxyl functional group and the process is carried out in the absence of added methyl acetate;
wherein the at least one compound containing a hydroxyl functional group is one or more hydroxyl compound(s) selected from water, C 1 -C 4 aliphatic alcohols, and C 1 -C 4 aliphatic carboxylic acids; and
wherein the zeolite is a templated zeolite.
15. A process according to claim 1 , wherein
the molar ratio of hydrogen to carbon monoxide is in the range 1 to 12:1;
the total amount of hydroxyl compound(s) is from 0.01 to 0.5 mol % based on the total gaseous feed to the process; and
the amount of dimethyl ether is from 1.0 to 20 mol % based on the total gaseous feed to the process.
16. A process according to claim 1 , wherein
the molar ratio of hydrogen to carbon monoxide is in the range 1 to 8:1;
the total amount of hydroxyl compound(s) is from 0.01 to 0.5 mol % based on the total gaseous feed to the process; and
the amount of dimethyl ether is from 1.5 to 15 mol % based on the total gaseous feed to the process.
17. A process according to claim 1 , wherein
the molar ratio of hydrogen to carbon monoxide is in the range 1.5 to 4:1;
the total amount of hydroxyl compound(s) is from 0.01 to 0.5 mol % based on the total gaseous feed to the process; and
the amount of dimethyl ether is from 1.5 to 15 mol % based on the total gaseous feed to the process.
18. A process according to claim 1 , wherein
the molar ratio of hydrogen to carbon monoxide is in the range 1.5 to 4:1;
the hydroxyl compound is acetic acid, present in an amount from 0.01 to 0.5 mol % based on the total gaseous feed to the process; and
the zeolite has a framework type selected from the group consisting of MOR, FER, OFF, CHA, GME, MFS, EON and ETR.
19. A process according to claim 1 , wherein
the molar ratio of hydrogen to carbon monoxide is in the range 1.5 to 4:1;
the hydroxyl compound is methanol, present in an amount from 0.01 to 0.5 mol % based on the total gaseous feed to the process; and
the zeolite has a framework type selected from the group consisting of MOR, FER, OFF, CHA, GME, MFS, EON and ETR.
20. A process according to claim 1 , wherein
the molar ratio of hydrogen to carbon monoxide is in the range 1.5 to 4:1;
the hydroxyl compound is water, present in an amount from 0.01 to 0.5 mol % based on the total gaseous feed to the process; and
the zeolite has a framework type selected from the group consisting of MOR, FER, OFF, CHA, GME, MFS, EON and ETR.