Diphosphites with a dicyclohexylphosphino radical

Abstract

Diphosphites with a dicyclohexylphosphino radical and use thereof in hydroformylation.

Claims

1. Compound of formula (I): ##STR00008## where R.sup.1, R.sup.2, R.sup.3, R.sup.4 are selected from: (C.sub.1-C.sub.12)-alkyl, O(C.sub.1-C.sub.12)-alkyl.

2. Compound according to claim 1, wherein R.sup.1 is selected from: OCH.sub.3, -.sup.tertBu.

3. Compound according to claim 1, wherein R.sup.1 is -.sup.tertBu.

4. Compound according to claim 1, wherein R.sup.2 is selected from: OCH.sub.3, -.sup.tertBu.

5. Compound according to claim 1, wherein R.sup.2 is -.sup.tertBu.

6. Compound according to claim 1, wherein R.sup.2 is OCH.sub.3.

7. Compound according to claim 1, wherein R.sup.3 is selected from: OCH.sub.3, -.sup.tertBu.

8. Compound according to claim 1, wherein R.sup.3 is -.sup.tertBu.

9. Compound according to claim 1, wherein R.sup.4 is selected from: OCH.sub.3, -.sup.tertBu.

10. Compound according to claim 1, wherein R.sup.4 is -.sup.tertBu.

11. Compound according to claim 1, wherein R.sup.4 is OCH.sub.3.

12. Compound according to claim 1, wherein the compound has the structure (1) or (2): ##STR00009##

13. Process comprising the process steps of: a) initially charging an olefin; b) adding a compound according to claim 1; c) adding a Rh compound; d) feeding in H.sub.2 and CO; e) heating the reaction mixture from a) to d), to convert the olefin to an aldehyde.

14. Process according to claim 13, wherein the Rh compound is selected from: Rh(acac)(CO).sub.2, [(acac)Rh(COD)] (Umicore, acac=acetylacetonate anion; COD=1,5-cyclooctadiene), Rh.sub.4CO.sub.12.

15. Process according to claim 13, wherein the Rh compound is Rh(acac)(COD).

Description

[0034] The invention shall be elucidated in more detail hereinbelow with reference to working examples.

Synthese (1): 4,8-Di-tert-butyl-6-((3,3-di-tert-butyl-2-((dicyclohexylphosphanyl)oxy)-5,5-dimethoxy-[1,1-biphenyl]-2-yl)oxy)-2,10-dimethoxydibenzo[d,f][1,3,2]dioxaphosphepine

[0035] ##STR00005##

[0036] To a solution of 3,3-di-tert-butyl-2-((4,8-di-tert-butyl-2,10-dimethoxydibenzo[d,f][1,3,2]dioxaphosphepin-6-yl)oxy)-5,5-dimethoxy-[1,1-biphenyl]-2-ol (0.6749 g; 0.906 mmol) in THF (9 ml) is added dropwise at ?20? C. a 0.533M solution of n-butyllithium (1.7 ml; 0.906 mmol) in hexane. The mixture is stirred for 20 min at this temperature, allowed to warm to 0? C. and a solution of chlorodicyclohexylphosphine (0.2214 g; 0.9513 mmol) in THF (4 ml) is added. The mixture is allowed to warm to room temperature, stirred overnight and the solvent removed in vacuo. The residue is taken up in toluene (9 ml), the resulting mixture is filtered, the filtrate concentrated in vacuo and dried at 50? C./0.1 mbar for 2 h. The residue obtained is crystallized from hot acetonitrile (8 ml). Filtration and vacuum drying gives 0.630 g (0.670 mmol, 74%).

[0037] Elemental analysis (calculated for C.sub.56H.sub.78O.sub.8P.sub.2=941.18 g/mol): C=71.35 (71.47); H=8.40 (8.35); P=6.42 (6.58)%.

[0038] ESI-TOF HRMS: m/z=941.5244; [M++H], calculated m/z=941.5250.

Synthese (2): 2,4,8,10-Tetra-tert-butyl-6-((3,3,5,5-tetra-tert-butyl-2-((dicyclohexylphosphanyl)oxy)-[1,1-biphenyl]-2-yl)oxy)dibenzo[d,f][1,3,2]dioxaphosphepine

[0039] ##STR00006##

[0040] To a solution of 3,3,5,5-tetra-tert-butyl-2-((2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphepin-6-yl)oxy)-[1,1-biphenyl]-2-ol (0.4897 g; 0.5766 mmol) in THF (5 ml) is added dropwise at ?20? C. a 0.533M solution of n-butyllithium (1.14 ml; 0.6054 mmol) in hexane. The mixture is stirred for 20 min at this temperature, allowed to warm to 0? C. and a solution of chlorodicyclohexylphosphine (0.1436 g; 0.6170 mmol) in THF (3 ml) is added. The mixture is allowed to warm to room temperature, stirred overnight and the solvent removed in vacuo. The residue is taken up in toluene (9 ml), the resulting mixture is filtered, the filtrate concentrated in vacuo and dried at 50? C./0.1 mbar for 2 h. The residue is dissolved in THF (3.5 ml). The solid precipitated after addition of acetonitrile (ca. 5 ml) is filtered, washed with a little acetonitrile and dried. Yield: 0.272 g (0.260 mmol, 45%).

[0041] Elemental analysis (calculated for C.sub.68H.sub.102O.sub.4P.sub.2=1045.50 g/mol): C=78.23 (78.12); H=9.74 (9.83); P=5.71 (5.93)%.

[0042] ESI-TOF HRMS: m/z=1045.7322; [M++H], calculated m/z=1045.7332.

Synthese (3): ((3,3,5,5-Tetra-tert-butyl-[1,1-biphenyl]-2,2-diyl)bis(oxy)bis (dicyclohexylphosphane)

[0043] ##STR00007##

[0044] To a solution of 3,3,5,5-tetra-tert-butyl-[1,1-biphenyl]-2,2-diol (0.6832 g; 1.6638 mmol) in THF (12 ml) is added dropwise at ?20? ? C. a 0.533M solution of n-butyllithium (6.56 ml; 3.494 mmol) in hexane. The mixture is stirred for 20 min at this temperature, allowed to warm to 0? C. and a solution of chlorodicyclohexylphosphine (0.8287 g; 3.5606 mmol) in THF (6 ml) is added. The mixture is allowed to warm to room temperature, stirred overnight and the solvent removed in vacuo. The residue is taken up in toluene (20 ml), the resulting mixture is filtered, the filtrate concentrated in vacuo and dried at 50? C./0.1 mbar for 2 h. The residue is dissolved in THF (6 ml). The solid precipitated after addition of acetonitrile (4 ml) is filtered and dried. Yield: 0.469 g (0.582 mmol, 35%).

[0045] ESI-TOF HRMS: m/z=803.6021; [M++H]; calculated m/z=803.6025.

Catalysis Experiments

[0046] The hydroformylation was conducted in a 200 ml autoclave from Premex Reactor AG, Lengau, Switzerland, equipped with pressure-retaining valve, gas flowmeter, sparging stirrer and pressure pipette. To minimize the influence of moisture and oxygen, the toluene used as solvent was purified in a Pure Solv. MD-7 system and stored under argon. The olefin cis/trans-2-pentene used as substrate (Aldrich) was heated at reflux over sodium and distilled under argon. Toluene solutions of the catalyst precursor and of the ligand were mixed in the autoclave under an argon atmosphere. [(acac)Rh(COD)] (Umicore, acac=acetylacetonate anion; COD=1,5-cyclooctadiene) was used as catalyst precursor. The autoclave was heated with stirring (1500 rpm) at 12 bar for a final pressure of 20 bar. After reaching the reaction temperature, the olefin was injected into the autoclave by way of a positive pressure established in the pressure pipette. The reaction was carried out at a constant pressure of 20 bar (closed-loop pressure controller from Bronkhorst, the Netherlands) over 4 h. At the end of the reaction time, the autoclave was cooled to room temperature, depressurized while stirring and purged with argon. 1 ml of reaction mixture was removed immediately after the stirrer had been switched off, diluted with 10 ml of pentane and analysed by gas chromatography: HP 5890 Series II plus, PONA, 50 m?0.2 mm?0.5 ?m.

[0047] The experiment was carried out with compounds (1), (2) and (3).

[0048] The compound (3) serves here as reference ligand.

Results of the Catalysis Experiments

[0049] [Rh]: 100 ppm, p: 20 bar, T: 120? C.; t: 4 h; Rh:L=1:2

TABLE-US-00001 TABLE Hydroformylation of cis/trans-2-pentene Ligand Aldehyde yield [%] (1)* 94 (2)* 99 (3) <1 *inventive compound

[0050] The experiments carried out demonstrate that the stated object is achieved by a compound according to the invention.