Platinum complexes having benzyl-based diphosphine ligands for the catalysis of the alkoxycarbonylation of ethylenically unsaturated compounds

Abstract

Platinum complexes having benzyl-based diphosphine ligands for the catalysis of the alkoxycarbonylation of ethylenically unsaturated compounds.

Claims

1-7. (canceled)

8. Process comprising the process steps of: a) initially charging an ethylenically unsaturated compound; b) adding a complex comprising Pt and a compound of formula (I) ##STR00010## or adding a compound having formula (I) ##STR00011## where R.sup.1 R.sup.2, R.sup.3, R.sup.4 are each independently selected from —(C.sub.1-C.sub.12)-alkyl, —(C.sub.3-C.sub.12)-cycloalkyl, —(C.sub.3-C.sub.12)-heterocycloalkyl, —(C.sub.6-C.sub.20)-aryl, —(C.sub.6-C.sub.20)-heteroaryl; at least one of the R.sup.1, R.sup.2, R.sup.3, R.sup.4 radicals is a —(C.sub.6-C.sub.20)-heteroaryl radical having at least six ring atoms; and R.sup.1 R.sup.2, R.sup.3, R.sup.4, if they are —(C.sub.1-C.sub.12)-alkyl, —(C.sub.3-C.sub.12)-cycloalkyl, —(C.sub.3-C.sub.12)-heterocycloalkyl, —(C.sub.6-C.sub.20)-aryl or —(C.sub.6-C.sub.20)-heteroaryl, may each independently be substituted by one or more substituents selected from: —(C.sub.1-C.sub.12)-alkyl, —O—(C.sub.1-C.sub.12)-alkyl, —OH, —NH.sub.2, halogen, and a substance comprising Pt; c) adding an alcohol; d) feeding in CO; e) heating the reaction mixture from a) to d), with conversion of the ethylenically unsaturated compound to an ester.

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 alcohol in process step c) is selected from: methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 2-propanol, tent-butanol, 3-pentanol, cyclohexanol, phenol.

11. Process according to claim 8, wherein the alcohol in process step c) is methanol.

12. Process according to claim 8, wherein the substance comprising Pt is selected from: platinum dichloride (PtCl.sub.2), platinum(II) acetylacetonate [Pt(acac).sub.2], platinum(II) acetate [Pt(OAc).sub.2], dichloro(1,5-cyclooctadiene)platinum(II) [Pt(cod).sub.2Cl.sub.2], bis(dibenzylideneacetone)platinum [Pt(dba).sub.2], bis(acetonitrile)dichloroplatinum(II) [Pt(CH.sub.3CN).sub.2Cl.sub.2], (cinnamyl)platinum dichloride [Pt(cinnamyl)Cl.sub.2].

13. Process according to claim 8, wherein the substance comprising Pt is selected from: platinum dichloride (PtCl.sub.2), platinum(II) acetylacetonate [Pt(acac).sub.2], platinum(II) acetate [Pt(OAc).sub.2].

Description

[0040] The invention is to be illustrated in detail hereinafter by a working example.

Conversion of 1-Octene to the Methyl Ester

[0041] ##STR00005##

[0042] Reaction conditions: 1-Octene (1.0 mmol), PtCl.sub.2 (0.01 mmol, 1.0 mol %), ligand: monodentate phosphine ligand (0.04 mmol, 4.0 mol %), bidentate phosphine ligand (0.02 mmol, 2.0 mol %), PTSAH.sub.2O (monohydrate of p-toluenesulfonic acid) (5.0 mol %), MeOH (2.0 ml), pressure (CO): 40 bar, temperature: 120° C., reaction time: 20 h.

[0043] The reaction was conducted with the following ligands:

Monodentate Phosphine:

[0044] ##STR00006## ##STR00007##

Bidentate Phosphine Ligands:

[0045] ##STR00008## ##STR00009##

[0046] The respective yield and n/iso selectivity are stated below the ligand. Selectivities and yields were determined by gas chromatography with mesitylene as internal standard.

[0047] Of the 16 ligands used, 11 did not give any conversion (0%). Only with one ligand (L12=(1)) was it possible to achieve a conversion of more than 60%. As shown by the series experiments, the greatest conversion is achieved with the inventive complex of Pt and (1).

[0048] The cost of Pt is below that of Pd. The object is thus achieved by a complex according to the invention.