Continuous process for the carbonylation of ethylene

1. A continuous process for the carbonylation of ethylene in a liquid phase using carbon monoxide in the presence of a co-reactant having a mobile hydrogen atom and a suitable catalyst system comprising the steps of:

(i) forming a liquid phase comprising the co-reactant having a mobile hydrogen atom and the suitable catalyst system;

the catalyst system obtainable by combining:

(a) a metal of Group 8, 9 or 10 or a suitable compound thereof;

(b) a ligand of general formula (I)

wherein

the groups X 3 and X 4 independently represent univalent radicals of up to 30 atoms or X 3 and X 4 together form a bivalent radical of up to 40 atoms and X 5 has up to 400 atoms;

Q 1 represents phosphorus, arsenic or antimony; and

c) optionally, a source of anions;

(ii) forming a gaseous phase in contact with the liquid phase by providing at least an ethylene gas input feed stream and a carbon monoxide gas input feed stream wherein the ethylene:CO molar ratio entering the liquid phase from the input feed streams is greater than 2:1; and

(iii) reacting ethylene with carbon monoxide in the presence of the co-reactant, and of the suitable catalyst system in the liquid phase;

wherein the ethylene:CO gas molar ratio in the gaseous phase is between 20:1 and 1000:1.

2. The process according to claim 1 , wherein the catalyst is replenished as the reaction proceeds.

3. The process according to claim 1 , wherein the catalyst concentration is generally maintained throughout the continuous reaction so that the rate of addition matches the rate of catalyst decay.

4. The process according to claim 1 , wherein the ethylene and carbon monoxide input feed streams are combined into a single input feed stream prior to contact with the liquid phase and therefore the ethylene:CO molar ratio in the single combined input feed stream is greater than 2:1.

5. The process according to claim 1 , wherein the ethylene:CO gas molar ratio in the gaseous phase of the reactor is between 40:1 and 200:1.

6. The process according to claim 1 , wherein the ethylene:CO gas molar ratio in the reactor is either between 30:1 and 49:1 or 51:1 and 150:1.

7. The process according to claim 1 , wherein the ethylene:CO molar ratio in the gaseous input feed stream(s) of the reactor, including any recycled ethylene and CO, is between 2:1 and 20:1.

8. The process according to claim 1 , wherein the molar ratio of ethylene:CO in the liquid phase is greater than 10:1.

9. A continuous process for the carbonylation of ethylene in a liquid phase using carbon monoxide in the presence of a co-reactant having a mobile hydrogen atom and a suitable catalyst system comprising the steps of:

(i) forming a liquid phase comprising the co-reactant having a mobile hydrogen atom and the suitable catalyst system;

the catalyst system obtainable by combining:

(a) a metal of Group 8, 9 or 10 or a suitable compound thereof;

(b) a ligand of general formula (I)

wherein

the groups X 3 and X 4 independently represent univalent radicals of up to 30 atoms or X 3 and X 4 together form a bivalent radical of up to 40 atoms and X 5 has up to 400 atoms;

Q 1 represents phosphorus, arsenic or antimony; and

c) optionally, a source of anions;

(ii) forming a gaseous phase in contact with the liquid phase by providing at least an ethylene gas input feed stream and a carbon monoxide gas input feed stream to the liquid phase; and

(iii) reacting ethylene with carbon monoxide in the presence of the co-reactant, and of the suitable catalyst system in the liquid phase;

wherein the molar ratio of ethylene:CO in the liquid phase is greater than 10:1.

10. The process according to claim 1 , wherein the ethylene:CO molar ratio entering the liquid phase from the input feed streams is greater than 2:1.

11. The process according to claim 1 , wherein preferably, the liquid phase is well mixed during the reaction.

12. The process according to claim 1 , wherein the liquid phase is mixed using a dual impeller mixer which mixes in two opposed directions in the reactor so that forward flow and back flow are achieved simultaneously.

13. The process according to claim 1 , wherein the phosphine, arsine or stibine ligand is a bidentate ligand, wherein X 5 represents

wherein H is a bivalent organic bridging group with 1-6 atoms in the bridge;

and the groups X 1 , X 2 , X 3 and X 4 independently represent univalent radicals of up to 30 atoms, optionally having at least one tertiary carbon atom via which the group is joined to the Q 1 or Q 2 atom, or X 1 and X 2 and/or X 3 and X 4 together form a bivalent radical of up to 40 atoms, optionally having at least two tertiary carbon atoms via which the radical is joined to the Q 1 and/or Q 2 atom.

14. A process according to claim 1 , wherein the ethylene:CO gas molar ratio in the reactor is between 51:1 and 150:1.