Carbonylation catalyst and process
View Patent ↗A catalyst and process for the production of methyl acetate by contacting dimethyl ether and carbon monoxide in the presence of a catalyst which is a zeolite of micropore volume of 0.01 ml/g or less.
1. A catalyst for the carbonylation of dimethyl ether with carbon monoxide to produce methyl acetate wherein the catalyst comprises an dried but uncalcined crystalline microporous aluminosilicate zeolite of micropore volume of 0.01 ml/g or less and which zeolite
is selected from zeolites of framework type MOR, FER, CHA, OFF, MFS and GME;
is in an ion-exchanged ammonium or hydrogen form; and
contains at least one channel which is defined by an 8-member ring,
wherein an organic structure directing agent selected from salts and bases of quaternary ammonium compounds is used to prepare the zeolite, which is not subsequently removed from or not substantially removed from the zeolite as synthesized.
2. The catalyst according to claim 1 wherein the 8-member ring is interconnected with at least one channel defined by a ring with 10 or 12 members.
3. The catalyst according to claim 1 wherein the zeolite has the framework type MOR and is a mordenite.
4. The catalyst according to claim 3 wherein the mordenite is in an ammonium form.
5. The catalyst according to claim 3 wherein the mordenite has the framework elements, silicon, aluminium and at least one of gallium, boron and iron.
6. The catalyst according to claim 5 wherein the framework elements are silicon, aluminium and gallium.
7. The catalyst according to claim 1 wherein the zeolite micropore volume is from 0.00 ml/g to 0.01 ml/g.
8. The catalyst according to claim 1 wherein the zeolite contains 4% or greater by weight of carbon.
9. The catalyst according to claim 8 wherein the zeolite contains 4% to 5% by weight of carbon.
10. The catalyst according to claim 1 wherein the zeolite is composited with a binder material.
11. The catalyst according to claim 1 wherein the zeolite is prepared from a synthesis mixture comprising a source of silica, a source of alumina, a source of alkali or alkaline earth metal, water and the organic structure directing agent.
12. The catalyst according to claim 1 wherein the zeolite is prepared by a process which comprises the steps:
(i) preparing the zeolite from a synthesis mixture which contains the organic structure directing agent;
(ii) treating the as-synthesised zeolite with an aqueous solution of ammonium ions;
(iii) drying the ammonium treated zeolite; and
wherein the organic structure directing agent is not removed or not substantially removed from the zeolite.
13. The catalyst according to claim 1 wherein the quaternary ammonium compound is a tetraalkyl ammonium compound.
14. The catalyst according to claim 13 wherein the tetraalkyl ammonium compound is a tetraalkylammonium salt.
15. The catalyst according to claim 14 wherein the tetraalkyl ammonium salt is tetraalkylammonium bromide.
16. The catalyst according to claim 11 wherein the synthesis mixture further comprises a source of gallium oxide.
17. The catalyst according to claim 1 , wherein the zeolite has the framework type MOR and is a mordenite, the organic structure directing agent is a tetraalkyl ammonium salt or base, and the zeolite contains 4% or greater by weight of carbon.