PROCESS FOR PREPARING AN UNSATURATED CARBOXYLIC ACID SALT

Abstract

Catalytic process for preparing an α,β-ethylenically unsaturated carboxylic acid salt, comprising reacting an alkene and carbon dioxide in the presence of a carboxylation catalyst and releasing the α,β-ethylenically unsaturated carboxylic acid salt with a base, the carboxylation catalyst being a transition metal complex, which comprises a structurally constrained bidentate P,X ligand, wherein X is selected from the group consisting of P, N, O, and carbene, the P and X atom are separated by 2 to 4 bridging atoms, and wherein the bridging atoms are part of at least one 5- to 7-membered cyclic substructure. A further catalytic processes for preparing α-βethylenically unsaturated carboxylic acid derivatives from CO.sub.2 and an alkene is provided.

Claims

1: A catalytic process for preparing an α,β-ethylenically unsaturated carboxylic acid salt, the process comprising reacting an alkene and carbon dioxide in the presence of a carboxylation catalyst and releasing the α,β-ethylenically unsaturated carboxylic acid salt with a base, wherein: the carboxylation catalyst is a transition metal complex comprising a structurally constrained bidentate P,X ligand: X is selected from the group consisting of P, N, O, and a carbene; the P and X atoms of the P,X ligand are separated by 2 to 4 bridging atoms; and the bridging atoms are contained in at least one 5- to 7-membered cyclic substructure.

2: The catalytic process according to claim 1, wherein the structurally constrained bidentate ligand is a P,X ligand is a P,P ligand in which: each bridging atom is directly linked to a P atom, together with the P atom to which it is linked, and the bridging atoms are contained in a 5 to 7-membered cyclic substructure; or two neighboring bridging stomas are contained in a 5- to 7-membered cyclic substructure.

3: The catalytic process according to claim 1, wherein the structurally constrained bidentate P,X ligand is selected from the group consisting of: a ligand of formula (IIa) ##STR00017## wherein R.sup.6 is independently selected from the group consisting of CHR.sup.7.sub.2, CR.sup.7.sub.3, and a C.sub.3-C.sub.8-cycloalkyl, R.sup.7 is independently a linear C.sub.1-C.sub.4-alkyl, A.sup.1 together with carbon atoms to which it is bound and an interjacent phosphorous atom forms a 5- to 7-membered cyclic substructure, and R.sup.8 is independently selected from the group consisting of hydrogen, a C.sub.1-C.sub.12-alkyl, a C.sub.3-C.sub.12-cycloalkyl, C.sub.3-C.sub.12-heterocycloalkyl, a C.sub.6-C.sub.14-aryl, a C.sub.6-C.sub.14-heteroaryl, C.sub.1-C.sub.12-alkoxy, a C.sub.3-C.sub.12-cycloalkoxy, a C.sub.3-C.sub.12-heterocycloalkoxy, a C.sub.6-C.sub.14-aryloxy, and a C.sub.6-C.sub.14-heteroaryloxy; a ligand of formula (IIb) ##STR00018## wherein R.sup.10 is independently selected from the group consisting of a C.sub.1-C.sub.8-alkyl and a C.sub.3-C.sub.8-cycloalkyl, R.sup.11 is independently selected from the group consisting of CHR.sup.10.sub.2, CR.sup.10.sub.3, and a C.sub.3-C.sub.8-cycloalkyl, X is independently selected from the group consisting of C—H, C—CH.sub.3, and N, and A.sup.2 together with moieties X to which it is bound and interjacent carbon atoms forms a 5- to 7-membered cyclic substructure; and a ligand of formula (IIc) ##STR00019## wherein R.sup.13 and R.sup.14 are independently a C.sub.3-C.sub.8-cycloalkyl, and R.sup.15 is H, O—C.sub.1-C.sub.6-alkyl, or both R.sup.15 together constitute a —CH═CH— bridge.

4: The catalytic process according to claim 3, wherein: the structurally constrained bidentate P,X ligand is a ligand of formula (IIa); and R.sup.6 is CR.sup.7.sub.3.

5: The catalytic process according to claim 3, wherein: the structurally constrained bidentate P,X hand is a ligand of formula (IIa); and A.sup.1 is selected from the group consisting of ethylene, ethenylene, 1,2-phenylene, 1,2-naphthylene, 2,3-naphthylene, and formula: ##STR00020##

6: The catalytic process according to claim 3, wherein: the structurally constrained bidentate P,X ligand is a ligand of formula (IIb); and each R.sup.10 is independently selected from the group consisting of a C.sub.1-C.sub.6-alkyl and a C.sub.3-C.sub.7-cycloalkyl; and R.sup.11 is CR.sup.10.sub.3.

7: The catalytic process according to claim 3, wherein: the structurally constrained bidentate P,X ligand is a ligand of formula (IIb); and A.sup.2 is a —CH═CH— bridge.

8: The catalytic process according to claim 3, wherein: the structurally constrained bidentate P,X ligand is a ligand of formula (IIc); and R.sup.15 is H or OCH.sub.3.

9: The catalytic process according to claim 3, wherein: the structurally constrained bidentate P,X ligand is a ligand of formula (IIb); and X is CH.

10: The catalytic process according to claim 1, wherein the structurally constrained bidentate P,X ligand is selected from the group consisting of ##STR00021## wherein Cy represents cyclohexyl.

11: The catalytic process according to claim 1, wherein the transition metal complex is a nickel complex.

12: The catalytic process according to claim 1, wherein: the alkene is ether; and the α,β-ethylenically unsaturated carboxylic acid is acrylic acid.

13: The catalytic process according to claim 1, wherein the alkene and the carbon dioxide are reacted in the presence of a reducing agent.

14: The catalytic process according to claim 1, wherein the reacting occurs in the presence of a reaction medium comprising an aprotic organic solvent.

15: The catalytic process according to claim 14, wherein the aprotic organic solvent is selected from the group consisting of a cyclic alkyl ether having 4 to 8 carbon atoms, a dialkyl ether having 2 to 12 carbon atoms, a cycloalkyl alkyl ether having 4 to 12 carbon atoms, an aryl alkyl ether having 7 to 16 carbon atoms, a biaryl having 12 to 16 carbon atoms, a diaryl oxide having 12 to 16 carbon atoms, a C.sub.1-C.sub.8-alkyl ester of a C.sub.6-C.sub.10-aryl monocarboxylic acid, a di-C.sub.1-C.sub.8-alkyl ester of a C.sub.6-C.sub.10-aryl dicarboxylic acid, a dialkyl carbonate having 3 to 13 carbon atoms, a diether consisting of a dioxyalkylene residue having 2 to 8 carbon atoms and two C.sub.1-C.sub.8-alkyl residues, a benzenes wherein 1 to 4 hydrogen atoms are substituted by 1 to 4 C.sub.1-C.sub.4-alkyl residues, a halogenated benzene, an alkane having 5 to 18 carbon atoms, and mixtures thereof.

16: The catalytic process according to claim 1, wherein the base is an aryloxide.

17: The catalytic process according to claim 16, wherein the aryloxide is selected from the group consisting of sodium 2-fluorophenolate, sodium 3-fluorophenolate, sodium 2-chlorophenolate, and sodium 3-chlorophenolate.

18: The catalytic process according to claim 16, wherein the aryloxide is selected from the group consisting of sodium 2,6-dimethyl phenolate, sodium 2,6-diisopropyl phenolate, sodium 2-methyl-6-tert-butyl phenolate, sodium 2,6-di-tert-butyl phenoxide, sodium 2,6-dimethyl phenolate, sodium 2,6-dimethyl-4-tert-butyl phenolate, sodium 2,4,6-trimethyl phenolate, sodium 2,6-di-tert-butyl-4-methyl phenolate, sodium 2,6-di-tert-butyl-4-see-butyl phenolate, and 2,4,6-tri-tert-butyl phenolate.

19: The catalytic process according to claim 1, wherein: the reacting occurs in the presence of a reaction medium; the α,β-ethylenically unsaturated carboxylic acid salt is removed from the reaction medium; the removal of the α,β-ethylenically unsaturated carboxylic acid salt from the reaction medium comprises a liquid-liquid phase separation into a first liquid phase in which the α,β-ethylenically unsaturated carboxylic acid salt is enriched, and a second liquid phase in which the carboxylation catalyst, the base and a conjugate acid of the base are enriched; and the first and second liquid phases are obtained by contacting the reaction medium with a polar solvent.

20: The catalytic process according to claim 16, further comprising regenerating the aryloxide by adding an alkaline material.

Description

EXAMPLES 100 TO 103

[0233] The amount of base and conjugate acid being transferred from crude reaction products into aqueous phases was tested. The amount of aprotic organic solvent (THF), base and conjugate acid comprised by the crude reaction products are shown in Table 8.

TABLE-US-00008 TABLE 8 amount of conjugate amount of acid of the Ex. base THF base base 100 101 [00015] 30 mL 30 mL 18.6 mmol <0.1 mmol   1.4 mmol >9.9 mmol 102 103 [00016] 30 mL 30 mL 19.4 mmol  4.6 mmol 0.6 mmol 5.4 mmol

[0234] Each crude reaction product was transferred from the autoclave into a glass bottle having a volume of 100 mL. The autoclave was washed with D.sub.2O (15 mL) and internal standard (NMe.sub.4I, 25.1 mg, 0.125 mmol, or 2,2,3,3-d.sub.4-3-(trimethylsilyl)propionic acid, 28.7 mg, 0.167 mmol, both in 5 mL D.sub.2O) was added. The autoclave was washed with D.sub.2O (5 mL). All D.sub.2O used for washing the autoclave was combined with the reaction medium. Diethyl ether (40 mL) was added to the combined phases and 2 mL of the aqueous phase were centrifuged in order to improve phase separation. The water phase was filtered and then evaporated. The solid residue was dissolved in D.sub.2O and .sup.1H NMR spectra were recorded of the D.sub.2O solution thus obtained in order to determine the amount of base (aryloxide) and its conjugate acid (arylhydroxide) transferred into the aqueous phase. While large peaks were observed for the alkene protons of the acrylate, there were no or only very small peaks originating from aliphatic protons (i.e. from the methyl protons of the tert-butyl groups comprised by the aryloxide). This shows, that no or only very little aryloxide and arylhydroxide was transferred into the aqueous phase.