Process for alkoxycarbonylation of olefins using synthesis gas

Abstract

Process for alkoxycarbonylation of olefins using synthesis gas.

Claims

1. Process comprising the process steps of: a) initially charging an olefin; b) adding a ligand of formula (I): ##STR00006## where R.sup.1 and R.sup.3 are each a (C.sub.3-C.sub.20)-heteroaryl radical, R.sup.2 and R.sup.4 are each (C.sub.1-C.sub.12)-alkyl; c) adding a compound comprising Pd; d) adding an alcohol; e) feeding in CO and H.sub.2, where the pressure with which H.sub.2 is fed in is at least 0.6 MPa (6 bar); f) heating the reaction mixture from steps a) to e), to convert the olefin to an ester.

2. Process according to claim 1, wherein CO is fed in with a pressure in the range from 1 MPa (10 bar) to 3 MPa (30 bar).

3. Process according to claim 1, wherein CO is fed in with a pressure in the range from 1.5 MPa (15 bar) to 2.5 MPa (25 bar).

4. Process according to claim 1, wherein H.sub.2 is fed in with a pressure in the range from 0.6 MPa (6 bar) to 2.9 MPa (29 bar).

5. Process according to claim 1, wherein H.sub.2 is fed in with a pressure in the range from 0.9 MPa (9 bar) to 2.1 MPa (21 bar).

6. Process according to claim 1, wherein the ratio of the pressures with which CO and H.sub.2 are fed in is in the range from 1:0.3 to 1:1.4.

7. Process according to claim 1, where R.sup.1, R.sup.3 are each selected from furyl, thienyl, pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, pyrazolyl, furazanyl, tetrazolyl, pyridyl, pyridazinyl, pyrimidyl, pyrazinyl, benzofuranyl, indolyl, isoindolyl, benzimidazolyl, quinolyl, isoquinolyl.

8. Process according to claim 1, where R.sup.2 and R.sup.4 are .sup.terBu.

9. Process according to claim 1, wherein the ligand in process step b) has the formula (1): ##STR00007##

10. Process according to claim 1, wherein the compound in process step c) comprising Pd is selected from palladium dichloride, palladium(II) acetylacetonate, palladium(II) acetate, dichloro(1,5-cyclooctadiene)palladium(II), bis(dibenzylideneacetone)palladium, bis(acetonitrile)dichloropalladium(II), (cinnamyl)palladium dichloride.

11. Process according to claim 1, wherein the compound in process step c) comprising Pd is Pd(acac).sub.2.

12. Process according to claim 1, wherein the alcohol in process step d) is selected from methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 2-propanol, tert-butanol, 3-pentanol, cyclohexanol, phenol, or mixtures thereof.

13. Process according to claim 1, wherein the alcohol in process step d) is methanol.

14. Process according to claim 1, wherein the process comprises the additional process step d) of: d) adding an acid selected from: aluminium triflate, sulfuric acid, methylsulfonic acid (MSA), para-toluenesulfonic acid (p-TSA).

15. Process according to claim 14, wherein the acid:ligand ratio is in the range from 1 mol:1 mol to 15 mol:1 mol.

Description

Experiment 1

[0038] ##STR00004## [0039] Pd (acac).sub.2: 0.04 mol % [0040] (1): 0.12 mol % [0041] Al(OTf).sub.3: 0.6 mol %

[0042] The experiment was conducted once with synthesis gas and, as a comparative experiment, with pure CO. The synthesis gas here was a mixture of CO and H.sub.2. In both experiments, CO was fed in with a pressure of 20 bar. In the experiment with synthesis gas, the H.sub.2 was likewise fed in at 20 bar, which established a total pressure of 40 bar.

[0043] Yield of ester: [0044] CO: 47% [0045] CO+H.sub.2:67%

Experiment 2 (Variation of H.SUB.2 .Pressure)

[0046] ##STR00005## [0047] Pd (acac).sub.2: 0.04 mol % [0048] (1): 0.12 mol % [0049] Al(OTf).sub.3: 0.6 mol %

[0050] The series of experiments was conducted with a constant CO pressure of 20 bar. The H.sub.2 pressure was varied according to the table below.

TABLE-US-00001 p(H.sub.2) [bar] Yield [%] 0 47 5 44 10 63 20 67 30 41 40 41

[0051] As shown by the experiments conducted, the yield was increased by the use of synthesis gas.