Platinum complexes having binaphthyldiphosphine ligands for the catalysis of the hydroxycarbonylation of ethylenically unsaturated compounds

1. Complex comprising Pt and a compound of formula (I)

where

R 1 , R 2 , R 3 , R 4 are each independently selected from —(C 1 -C 12 )-alkyl, —(C 6 -C 20 )-heteroaryl.

2. Complex according to claim 1 ,

wherein at least two of the R 1 , R 2 , R 3 , R 4 radicals are a —(C 6 -C 20 )-heteroaryl radical having at least six ring atoms.

3. Complex according to claim 1 ,

wherein the R 1 and R 3 radicals are each a —(C 6 -C 20 )-heteroaryl radical having at least six ring atoms.

4. Complex according to claim 1 ,

wherein the R 1 and R 3 radicals are each 2-pyridyl.

5. Complex according to claim 1 ,

wherein R 2 and R 4 are —(C 1 -C 12 )-alkyl.

6. Complex according to claim 1 ,

wherein R 2 and R 4 are tert-butyl.

7. Complex according to claim 1 ,

wherein the compound (I) has the structure (1):

8. Process comprising the process steps of:

a) initially charging an ethylenically unsaturated compound;

b) adding a complex according to claim 1 , or

a compound of formula (I)

where

R 1 , R 2 , R 3 , R 4 are each independently selected from —(C 1 -C 12 )-alkyl, —(C 6 -C 20 )-heteroaryl

and

a substance comprising Pt;

c) adding an acid;

d) feeding in CO;

e) heating the reaction mixture from a) to d), with conversion of the ethylenically unsaturated compound to a carboxylic acid.

9. Process according to claim 8 ,

wherein the ethylenically unsaturated compound is selected from: ethene, propene, 1-butene, cis- and/or trans-2-butene, isobutene, 1,3-butadiene, 1-pentene, cis- and/or trans-2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, hexene, tetramethylethylene, heptene, 1-octene, 2-octene, di-n-butene, or mixtures thereof.

10. Process according to claim 8 ,

wherein the acid in process step c) is selected from: acetic acid, perchloric acid, sulfuric acid, phosphoric acid, methylphosphonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, tert-butanesulfonic acid, p-toluenesulfonic acid (PTSA), 2-hydroxypropane-2-sulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, dodecylsulfonic acid, camphorsulfonic acid.

11. Process according to claim 8 ,

wherein the acid in process step c) is acetic acid.

12. Process according to claim 8 ,

wherein the substance comprising Pt is selected from: platinum dichloride (PtCl 2 ), platinum(II) acetylacetonate [Pt(acac) 2 ], platinum(II) acetate [Pt(OAc) 2 ], dichloro(1,5-cyclooctadiene)platinum(II) [Pt(cod) 2 Cl 2 ], bis(dibenzylideneacetone)platinum [Pt(dba) 2 ], bis(acetonitrile)dichloroplatinum(II) [Pt(CH 3 CN) 2 Cl 2 ], (cinnamyl)platinum dichloride [Pt(cinnamyl)Cl 2 ].

13. Process according to claim 8 ,

wherein the substance comprising Pt is selected from: platinum dichloride (PtCl 2 ), platinum(II) acetylacetonate [Pt(acac) 2 ], platinum(II) acetate [Pt(OAc) 2 ].