Process for the removal of catalytic metals and promoter metals from carbonylation process streams

1. A process for the selective removal of Iridium carbonylation catalyst metal and/or at least one promoter selected from the group consisting of ruthenium, osmium and rhenium from a liquid composition comprising a carbonylation product, iridium carbonylation catalyst metal and/or said promoter metal, corrosion metals and optionally alkali or alkaline earth metals which process comprises contacting said liquid composition with a chelating resin to remove at least a portion of the iridium carbonylation catalyst metal and/or at least one promoter metal contained in the liquid composition and wherein the chelating resin comprises at least one thiourea functional group.

2. A process according to claim 1 wherein the liquid composition comprises alkali or alkaline earth metals.

3. A process according to claim 2 wherein the alkali metal is selected from the group consisting of lithium, sodium and potassium.

4. A process according to claim 1 wherein the chelating resin is of formula:

wherein P represents a chemical backbone.

5. A process according to claim 4 wherein the chemical backbone, P, is a polymer.

6. A process according to claim 5 wherein the polymer is selected from the group consisting of polystyrene, polyacrylate, polymethacrylate, polyethylene and polypropylene.

7. A process according to claim 5 or claim 6 wherein the polymer is a crosslinked polymer.

8. A process according to claim 7 wherein the crosslinked polymer is a crosslinked polystyrene.

9. A process according to claim 8 wherein the crosslinked polystyrene is a divinylbenzene polystyrene.

10. A process according to claim 4 wherein the chemical backbone, P, is selected from the group consisting of silica, alumina, titania, ceria, zirconia, clays and zeolites.

11. A process according to claim 4 wherein the chemical backbone, P, has inorganic and organic moieties.

12. A process according to claim 1 wherein the chelating resin is a macroporous resin or a gel resin.

13. A process according to claim 1 wherein the liquid reaction composition further comprises rhodium carbonylation catalyst metal.

14. A process according to claim 1 wherein the process is operated as a batch, semi-continuous or continuous process.

15. A process according to claim 1 wherein the liquid composition is contacted with the chelating resin at a temperature in the range 0 to 100° C.

16. A process according to claim 1 wherein the liquid hourly space velocity of the liquid composition is in the range 1 to 20 h −1 .

17. A process according to claim 1 wherein the liquid composition is treated in-situ or offline.

18. A process according to claim 1 wherein the liquid composition is a process stream obtained from a carbonylation process to produce a carbonylation product which is a carboxylic acid.

19. A process according to claim 18 wherein the carboxylic acid is acetic acid.

20. A process according to claim 1 wherein the liquid composition further comprises one or more components selected from the group consisting of unconverted carbonylatable reactant, a solvent, water and iodide ions.

21. A process according to claim 1 wherein the liquid composition is a process stream obtained from the carbonylation of an alcohol and/or reactive derivative thereof in the presence of an iridium carbonylation catalyst, an alkyl halide co-catalyst, a catalyst promoter selected from ruthenium, osmium and rhenium and optionally a finite concentration of water.

22. A process according to claim 21 wherein the alcohol is methanol, the alkyl halide is methyl iodide, and the carbonylation is conducted with a finite concentration of water.

23. A process according to claim 1 wherein the liquid composition is to be treated is obtained from a distillation column stream.

24. A process according to claim 23 wherein the distillation column stream is selected from the group consisting of a stream from the base of a heavy ends column, a stream from the base of a combined light ends and drying column and a stream from a drying column.

25. A process according to claim 1 wherein the liquid composition is obtained from a gas phase carbonylation process.

26. A process according to claim 1 wherein the corrosion metal is selected from the group consisting of iron, nickel, chromium, manganese, zinc, molybdenum and mixtures thereof.