Process for the production of lactams

1. A homogenous process for the hydrogenation of dicarboxylic acids and/or derivatives thereof with an amine in the presence of a catalyst comprising:

(a) ruthenium or osmium; and

(b) an organic phosphine;

and wherein the hydrogenation is carried out in the presence of water.

2. A homogenous process according to claim 1 wherein the water is present in at least 1% by weight.

3. A homogenous process according to claim 1 wherein the dicarboxylic acid and/or derivative thereof is selected from one or more of dicarboxylic acids, polycarboxylic acids, anhydrides, monoesters or diester of dicarboxylic acids, monoamides or diamides of dicarboxylic acids, salts, such as amine salts, of dicarboxylic acids or mixtures.

4. A homogenous process according to claim 1 wherein the dicarboxylic acid and/or derivative thereof is a C 4 to C 12 dicarboxylic acid.

5. A homogenous process according to claim 1 wherein the dicarboxylic acid and/or derivative thereof is saturated or unsaturated.

6. A homogenous process according to claim 1 wherein the dicarboxylic acid and/or derivative thereof is selected from maleic acid, fumaric acid, succinic acid, maleic anhydride, adipic acid, and succinic anhydride.

7. A homogenous process according to claim 1 wherein the amine is NR 1 R 2 R 3 where R 1 , R 2 and R 3 are each hydrogen or alkyl and at least one of R 1 , R 2 and R 3 is alkyl.

8. A homogenous process according to claim 7 wherein the alkyl group is a C 1 to C 6 alkyl group.

9. A homogenous process according to claim 8 wherein the alkyl group is methyl, ethyl or propyl.

10. A homogenous process according to claim 1 wherein the amine is mixed with the dicarboxylic acid and/or derivatives thereof prior to undergoing the process.

11. A homogenous process according to claim 1 wherein the dicarboxylic acid and/or derivative thereof is converted to a corresponding amide by reaction with the amine prior to commencement of the hydrogenation.

12. A homogenous process according to claim 1 wherein the water is present as the solvent for the reaction.

13. A homogenous process according to claim 1 wherein one or both of the reactants or the product of the reaction are the solvent.

14. A homogenous process according to claim 1 wherein a solvent is used and water is present as an additive in the solvent.

15. A homogenous process according to claim 14 wherein the solvent is selected from tetraethyleneglycol dimethyl ether, N-methyl pyrrolidone, diethyl ether, ethyleneglycol dimethylether, dioxane, 2-propanol, 2-butanol, secondary alcohols, tertiary alcohols, lactams and N-methyl caprolactam.

16. A homogenous process according to claim 1 wherein the water is produced in situ as a by-product of the hydrogenation reaction.

17. A homogenous process according to claim 1 wherein the catalyst comprises ruthenium and the ruthenium is provided as a ruthenium compound.

18. A homogenous process according to claim 17 wherein the ruthenium compound is a compound selected from nitrates, sulphates, carboxylates, beta diketones, or carbonyls.

19. A homogenous process according to claim 1 wherein the ruthenium is present in an amount of from 0.005 to 1 mol, as ruthenium per liter of reaction solution.

20. A homogenous process according to claim 1 wherein the phosphine is a tridentate phosphine.

21. A homogenous process according to claim 1 wherein the phosphine is selected from trialkylphosphines, dialkylphosphines, monoalkylphosphines, triarylphosphines, diarylphosphines, monoarylphosphines, diarylmonoalkyl phosphines and dialkylmonoaryl phosphines.

22. A homogenous process according to claim 21 wherein the phosphine is selected from tris-1,1,1-(diphenylphosphinomethyl) methane,

tris-1,1,1-(diphenylphosphinomethyl)ethane,

tris-1,1,1-(diphenylphosphinomethyl)propane,

tris-1,1,1-(diphenylphosphinomethyl)butane,

tris-1,1,1-(diphenylphosphinomethyl)2, 2-dimethylpropane,

tris-1,3,5-(diphenylphosphinomethyl)cyclohexane,

tris-1,1,1-(dicyclohexylphosphinomethyl)ethane,

tris-1,1,1-(dimethylphosphinomethyl)ethane,

tris-1,1,1-(diethylphosphinomethyl)ethane,

1,5,9-triethyl-1,5,9-triphosphacyclododecane,

1,5,9-triphenyl-1,5,9-triphosphacyclododecane,

bis(2-diphenylphosphinoethyl)phenylphosphine,

bis-1,2-(diphenyl phosphino)ethane,

bis-1,3-(diphenyl phosphino)propane,

bis-1,4-(diphenyl phosphino)butane,

bis-1,2-(dimethyl phosphino)ethane,

bis-1,3-(diethyl phosphino)propane,

bis-1,4-(dicyclohexyl phosphino)butane,

tricyclohexylphosphine, trioctylphosphine,

trimethyl phosphine, tripyridyl phosphine and

triphenylphosphine.

23. A homogenous process according to claim 21

wherein the phosphine is selected from

tris-1,1,1-(diarylphosphinomethyl)alkane and

tris-1,1,1-(dialkylphosphinomethyl)alkane.

24. A homogenous process according to claim 1 wherein the catalyst is preformed.

25. A homogenous process according to claim 1 wherein the phosphine compound is present in an amount of from 0.0001 to 5 mol per liter of reaction solution.

26. A homogenous process according to claim 1 wherein the hydrogenation is carried out at temperatures from about 190° C. to about 300° C.

27. A homogenous process according to claim 1 wherein the reaction pressure is from about 500 psig to about 2000 psig.

28. A homogenous process according to claim 1 wherein the ratio of the amine to the dicarboxylic acid or derivative thereof is from about 0.5:1 to about 100:1.

29. A hornogenous process according to claim 1 wherein the ratio of the amine to the dicarboxylic acid or derivative thereof is from about 0.9:1 to about 2.0:1.

30. A homogenous process according to claim 1 wherein the product is a 2-pyrrolidone or an N-alkylated version thereof and the dicarboxylic acid or derivative thereof is maleic acid, maleic anhydride, succinic acid or succinic anhydride.

31. A homogenous process according to claim 1 wherein the product is caprolactam and the dicarboxylic acid or derivative thereof is adipic acid.

32. A homogenous process according to claim 1 wherein the catalyst is regenerated in the presence of the water and hydrogen.