Process for Pd-catalyzed hydroxycarbonylation of diisobutene: sulfuric acid/ligand ratio

Abstract

Process for Pd-catalyzed hydroxycarbonylation of diisobutene:sulfuric acid/ligand ratio.

Claims

1. A process for preparing compound P1 comprising: a) adding diisobutene to form a reaction mixture, b) adding a compound comprising Pd to the reaction mixture, wherein the Pd is capable of forming a complex, c) adding ligand L1 to the reaction mixture: ##STR00004## d) adding acetic acid to the reaction mixture, e) adding sulfuric acid to the reaction mixture, wherein the sulfuric acid is in an amount which is at least an amount between 3.5 and 5 mol of sulfuric acid per mole of ligand L1, f) feeding into the reaction mixture CO, g) heating the reaction mixture such that the diisobutene is converted to the compound P1: ##STR00005##

2. The process according to claim 1, wherein the compound in process step b) PdCl.sub.2, PdBr.sub.2, Pd(acac).sub.2, Pd(dba).sub.2 (dba=dibenzylideneacetone), or PdCl.sub.2(CH.sub.3CN).sub.2.

3. The process according to claim 1, wherein the sulfuric acid is added in an amount which is in the range from 3.5 mol to 4.5 mol of sulfuric acid per mole of ligand L1.

4. The 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 g).

5. The process according to claim 1, wherein the CO is fed in process step f) such that the reaction proceeds under a CO pressure in the range from 10 bar to 40 bar.

Description

(1) The invention is more particularly elucidated hereinbelow with reference to working examples.

(2) ##STR00003##

(3) A 4 ml vial was charged with [Pd(acac).sub.2] (1.75 mg, 0.25 mol %), L1 (11.83 mg, 1.0 mol %), H.sub.2SO.sub.4 (3.1 mg, 1.4 mol %) and a stirrer bar that had been dried in an oven. 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 (0.29 ml), acetic acid (0.85 ml) and diisobutene (DIBN) (2.3 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 CO pressure was increased to 15 bar at room temperature, and subsequently increased to a pressure of 25 bar with N.sub.2. The reaction was conducted at 120C for 3 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.

(4) The above-described experiment was repeated while varying the H.sub.2SO.sub.4/L1 ratio. All other parameters were maintained.

(5) The results are compiled in the following table.

(6) TABLE-US-00001 H.sub.2SO.sub.4/L1 (mmol/mmol) Conversion Entry H.sub.2SO.sub.4 (mol %) (%) 1 1.4/1-1.4 69 2 3.0/1-3.0 83 3* 3.75/1-3.75 90 4* 4.0/1-4.0 92 *inventive process

(7) As the experimental results show, the object is achieved by the inventive process.