PROCESS FOR THE DIRECT CONVERSION OF ALKENES TO CARBOXYLIC ACIDS

Abstract

Process for the direct conversion of alkenes to carboxylic acids.

Claims

1. Process comprising the process steps of: a) addition of an alkene; b) addition of a complex, comprising a compound according to structure (1) and also Pd, or a compound according to structure (1) and a substance comprising Pd ##STR00019## c) feeding in CO; d) heating the reaction mixture such that the alkene is converted to a carboxylic acid, wherein the alkene is directly converted to the carboxylic acid.

2. Process according to claim 1, wherein the substance in process step b) is selected from: PdCl.sub.2, PdBr.sub.2, Pd(acac).sub.2, Pd(dba).sub.2 (dba=dibenzylideneacetone), PdCl.sub.2(CH.sub.3CN).sub.2.

3. Process according to claim 1, wherein the process comprises the additional process step e): e) addition of acetic acid.

4. Process according to claim 1, wherein the process comprises additional process step f): f) addition of water.

5. Process according to claim 1, wherein the process comprises the additional process step g): g) addition of p-toluenesulfonic acid.

6. Process according to claim 1, wherein the reaction mixture is heated to a temperature in the range from 80 C. to 160 C. in process step d).

7. Process according to claim 1, wherein the CO is fed in in process step c) such that the reaction proceeds under a CO pressure in the range from 20 bar to 60 bar,

Description

[0024] The invention is more particularly elucidated hereinbelow with reference to working examples.

[0025] Variation of the Ligand

##STR00002## ##STR00003##

[0026] A 4 ml vial was charged with [Pd(acac).sub.2] (3.05 mg, 0.25 mol %), ligand (X) (1.0 mol %), para-toluenesulfonic acid (28.5 mg, 3.75 mol %) and an oven-dried stirrer bar. The vial was then sealed with septa (PTFE-coated styrene-butadiene rubber) and a phenol resin cap. The vial was evacuated and refilled with argon three times. H.sub.2O (0.5 ml), acetic acid (1.5 ml) and diisobutene (DIBN) (4.0 mmol) were added to the vial with a syringe. The vial was placed in an alloy plate, which was transferred to an autoclave (300 ml) of the 4560 series from Parr Instruments under argon atmosphere. After flushing the autoclave three times with CO, the pressure of CO was increased to 40 bar at room temperature. The reaction was conducted at 120 C. for 20 h. On conclusion of the reaction, the autoclave was cooled down to room temperature and cautiously decompressed. Isooctane (100 l) was then added as internal standard. Conversion was measured by GC analysis.

[0027] The above-described experiment was carried out with variation of the ligand (X), with X=1 to 8.

[0028] The results are compiled in the following table 1;

TABLE-US-00001 TABLE 1 Ligand Yield % (1)* >99 (2) 7 (3) 39 (4) 26 (5) 16 (6) 8 (7) 13 (8) 29 * inventive process

[0029] Variation of the Alkene

##STR00004##

[0030] A 4 ml vial was charged with [Pd(acac).sub.2] (3.07 mg, 0.25 mol %), ligand (1) (20.64 mg, 1.0 mol %), p-toluenesulfonic acid (28.5 mg, 3.75 mol %) and an oven-dried stirrer bar. The vial was then sealed with septa (PTFE-coated styrene-butadiene rubber) and a phenol resin cap. The vial was then connected to the atmosphere with a needle. The vial was evacuated and refilled with argon three times. H.sub.2O (0.5 ml), acetic acid (1.5 ml) and alkene (4.0 mmol) were added to the vial with a syringe. The vial was placed in an alloy plate, which was transferred to an autoclave (300 ml) of the 4560 series from Parr Instruments under argon atmosphere. After flushing the autoclave three times with CO, the pressure of CO was increased to 40 bar at room temperature. The reaction was conducted at 120 C. for 20 h. On conclusion of the reaction, the autoclave was cooled down to room temperature and cautiously decompressed. Isooctane (100 l) was then added as internal standard. Conversion was measured by GC analysis.

[0031] The experiment described above was repeated with variation of the alkene.

[0032] The results are compiled in the following table 2:

TABLE-US-00002 TABLE 2 Alkene Acid Yield [00005] [00006] 99% [00007] [00008] 98%, n/iso mixture [00009] [00010] 97%, iso mixture [00011] [00012] 99% [00013] [00014] 80% [00015] [00016] 95%, n/iso mixture [00017] [00018] 94%, n/iso mixture

[0033] As the experimental results show, the object is achieved by a process according to the invention.