Bisphosphite ligands based on benzopinacol with an open outer unit

Abstract

Bisphosphite ligands based on benzopinacol with an open outer unit, and the use thereof in hydroformylation.

Claims

1. A compound of formula (I): ##STR00008## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, R.sup.11, R.sup.12, R.sup.13, R.sup.14 are each independently selected from: —H, —(C.sub.1-C.sub.12)-alkyl, —O—(C.sub.1-C.sub.12)-alkyl or —(C.sub.4-C.sub.12)-aryl, and the radicals R.sup.1, R.sup.2, R.sup.3, R.sup.4, and also the radicals R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10, may form fused systems with one another.

2. The compound according to claim 1, wherein R.sup.11 and R.sup.14 are —(C.sub.1-C.sub.12)-alkyl.

3. The compound according to claim 1, wherein R.sup.11 and R.sup.14 are -.sup.tertBu.

4. The compound according to claim 1, wherein R.sup.2, R.sup.13 are selected from: —(C.sub.1-C.sub.12)-alkyl or, —O—(C.sub.1-C.sub.12)-alkyl.

5. The compound according to claim 1, wherein R.sup.12 and R.sup.13 are —OCH.sub.3 or -.sup.tertBu.

6. The compound according to claim 1, wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10 are selected from —H, —(C.sub.1-C.sub.12)-alkyl or —(C.sub.4-C.sub.12)-aryl.

7. The compound according to claim 1, wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, R.sup.8, R.sup.9, R.sup.10 are selected from —H, -.sup.tertBu, —(C.sub.4-C.sub.6)-aryl.

8. The compound according to claim 1, wherein the compound has one of the structures (1) to (3): ##STR00009##

9. A process comprising the process steps of: a) initially charging an ethylenically unsaturated compound; b) adding a compound according to claim 1; and a substance comprising Rh; c) feeding in H.sub.2 and CO, and d) heating the reaction mixture from a) to c), with conversion of the olefin to an aldehyde.

10. The process according to claim 9, wherein the ethylenically unsaturated compound in process step a) 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.

11. The process according to claim 9, wherein the substance comprising Rh is selected from: Rh(acac)(CO).sub.2, [(acac)Rh(COD)] (Umicore, acac=acetylacetonate anion; COD=1,5-cyclooctadiene), Rh.sub.4CO.sub.12.

12. The process according to claim 9, wherein CO is fed in in process step c) at a pressure in the range from 1 to 6 MPa (10 to 60 bar).

13. The process according to claim 9, wherein the reaction mixture is heated in process step d) to a temperature in the range from 80° C. to 160° C.

Description

(1) The invention shall be elucidated in more detail hereinbelow with reference to working examples.

Synthesis of bis(4-(tert-butyl)phenyl) (3,3-di-tert-butyl-5,5′-dimethoxy-2′-(4,4,5-tetraphenyl-1,3,2-dioxaphospholan-2-yl)oxy)-[1,1′-biphenyl]-2-yl) phosphite (1)

(2) ##STR00004##

(3) To a solution of 2-((3,3′-di-tert-butyl-2′-((dichlorophosphanyl)oxy)-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)oxy)-4,4,5,5-tetraphenyl-1,3,2-dioxaphospholane (0.7254 g; 0.8496 mmol) in 10 ml of toluene is added dropwise, at room temperature, a mixture of 4-tert-butylphenol (0.2808 g; 1.8691 mmol) and triethylamine (2.39 ml) in 8 ml of toluene. The mixture is stirred overnight and filtered, and the filtrate is concentrated to dryness under reduced pressure. The solid obtained is dried at 60° C./0.1 mbar for 2 h. Yield: 0.869 g (0.8036 mmol, 94%).

(4) Elemental analysis (calc. for C.sub.66H.sub.74O.sub.8P.sub.2=1081.273 g/mol): C=75.43 (75.53): H=7.06 (6.90); P=5.79 (5.73).

(5) ESI-TOF HRMS: m/z=1103.4775; [M.sup.++Na], calc. m/z=1103.4756.

(6) .sup.31P NMR (CD.sub.2Cl.sub.2): δ 132.2 (d, J.sub.PP=49 Hz); 145.3 (d, J.sub.PP=49 Hz).

(7) .sup.1H NMR (CD.sub.2Cl.sub.2): δ 1.15 (s, 9H); 1.33 (s, 9H); 1.35 (s, 9H); 1.53 (s, 9H); 3.55 (s, 3H); 3.76 (s, 3H); 6.71-7.43 (m, 32H) ppm.

Synthesis of 3,3′-di-tert-butyl-5,5′-dimethoxy-2′-((4,4,5,5-tetraphenyl-1,3,2-dioxaphospholan-2-yl)oxy)-[1,1′-biphenyl]-2-yl di(naphthalen-1-yl) phosphite (2):

(8) ##STR00005##

(9) To a solution of 2-((3,3′-di-tert-butyl-2′-((dichlorophosphanyl)oxy)-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)oxy)-4,4,5,5-tetraphenyl-1,3,2-dioxaphospholane (0.5622 g; 0.6585 mmol) in 8 ml of toluene is added dropwise, at room temperature, a mixture of 1-naphthol (0.2088 g; 1.4487 mmol) and triethylamine (1.85 ml) in 6 ml of toluene. The mixture is stirred overnight and filtered, and the filtrate is concentrated to dryness under reduced pressure. The solid obtained is dried at 60° C./0.1 mbar for 2 h and then taken up in 6 ml of hot acetonitrile. The solid obtained after storing the solution at −29° C. is separated off, washed with a little cold acetonitrile and dried. Yield: 0.480 g (0.449 mmol, 68%).

(10) Elemental analysis (calc. for C.sub.68H.sub.62O.sub.8P.sub.2=1069.178 g/mol): C=76.36 (76.39); H=5.95 (5.85); P=5.67 (5.79).

(11) ESI-TOF HRMS: m/z=1091.3801; [M.sup.++Na], calc. m/z=1091.3817.

(12) .sup.31P NMR (CD.sub.2Cl.sub.2): δ 135.5 (d, J.sub.PP=30 Hz); 146.2 (d, J.sub.PP=30 Hz) ppm.

(13) .sup.1H NMR (CD.sub.2Cl.sub.2): δ 1.14 (s, 9H); 1.63 (s, 9H); 2.94 (s, 3H); 3.87 (s, 3H); 6.33 (d, .sup.4J.sub.HH=3.1 Hz; 1H); 6.74 (d, .sup.4J.sub.HH=3.1 Hz; 1H); 6.89-7.84 (m, 35H); 8.12 (m, 1H) ppm.

Synthesis of 3,3′-di-tert-butyl-5,5′-dimethoxy-2′-((4,4,5,5-tetraphenyl-1,3,2-dioxaphospholan-2-yl)oxy)-[1,1′-biphenyl]-2-yl di(naphthalen-2-yl) phosphite (3):

(14) ##STR00006##

(15) To a solution of 2-((3,3′-di-tert-butyl-2′-((dichlorophosphanyl)oxy)-5,5′-dimethoxy-[1,1′-biphenyl]-2-yl)oxy)-4,4,5,5-tetraphenyl-1,3,2-dioxaphospholane (0.5971 g; 0.6993 mmol) in 8 ml of toluene is added dropwise, at room temperature, a mixture of 2-naphthol (0.2218 g; 1.5386 mmol) and triethylamine (1.96 ml) in 6 ml of toluene. The mixture is stirred overnight and filtered, and the filtrate is concentrated to dryness under reduced pressure. The solid obtained is dried at 60° C./0.1 mbar for 2 h and then taken up in 6.5 ml of hot acetonitrile. The solid obtained after storing the solution at −29° C. is separated off, washed with a little cold acetonitrile and dried. Yield: 0.470 g (0.439 mmol, 63%).

(16) Elemental analysis (calc. for C.sub.68H.sub.62O.sub.8P.sub.2=1069.178 g/mol): C=76.18 (76.39); H=5.88 (5.85); P=5.74 (5.79).

(17) ESI-TOF HRMS: m/z=1091.3811; [M.sup.++Na], calc. m/z=1091.3817.

(18) .sup.31P NMR (CD.sub.2Cl.sub.2): δ 131.8 (d, J.sub.PP=56 Hz); 145.0 (d, J.sub.PP=56 Hz) ppm.

(19) .sup.1H NMR (CD.sub.2CO.sub.2): δ 1.15 (s, 9H); 1.58 (s, 9H); 3.48 (s, 3H); 3.77 (s, 3H); 6.78 (m, 1H); 6.83 (m, 1H); 6.86 (m, 1H); 6.93-7.03 (m, 8H); 7.07-7.23 (m, 11); 7.35-7.52 (m, 10H); 7.66 (m, 1H): 7.72-7.85 (m, 5H) ppm.

(20) Catalysis Experiments

(21) The hydroformylation was conducted in a 200 ml autoclave from Premex Reactor AG, Lengau, Switzerland, equipped with pressure-retaining valve, gas flow meter, 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 conducted at a constant pressure (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 each 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 μm.

(22) The reaction was conducted using compounds (1) to (3) according to the invention and using the comparative ligand (D-1).

(23) ##STR00007##

(24) Reaction Conditions:

(25) Olefin: 2-pentene, solvent: toluene, proportion by mass of rhodium: 100 ppm, p: 20 bar, T: 120° C., t: 4 h, Rh:ligand ratio=1:2.

(26) The results are compiled in the following table:

(27) TABLE-US-00001 Yield of aldehyde Ligand [%] 1* 46 2* 45 3* 50 D-1 14 *compound according to the invention

(28) As the experimental results show, the problem is solved by the compounds according to the invention.