DIPHOSPHITES WITH AN OPEN, 3-METHYLATED OUTER UNIT

Abstract

Diphosphites having an open, 3-methylated outer unit and use thereof in hydroformylation.

Claims

1. Compound of the structure (I): ##STR00006## where R.sup.1, R.sup.2, R.sup.3, R.sup.4 are selected from: —H, —(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, R.sup.3 are selected from: —H, —(C.sub.1-C.sub.12)-alkyl.

3. Compound according to claim 1, where R.sup.1, R.sup.3 are —(C.sub.1-C.sub.12)-alkyl.

4. Compound according to claim 1, where R.sup.1, R.sup.3 are the same radical.

5. Compound according to claim 1, wherein R.sup.2, R.sup.4 are selected from: —H, —O—(C.sub.1-C.sub.12)-alkyl.

6. Compound according to claim 1, wherein R.sup.2, R.sup.4 are —O—(C.sub.1-C.sub.12)-alkyl.

7. Compound according to claim 1, where R.sup.2, R.sup.4 are the same radical.

8. Compound according to claim 1, where the compound has the structure (1): ##STR00007##

9. Use of a compound according to claim 1 in a ligand-metal complex for catalysis of a hydroformylation reaction.

10. Process comprising the process steps of: a) initially charging an olefin, b) adding a compound according to claim 1 and a substance containing a metal selected from: Rh, Ru, Co, Ir, c) supplying H.sub.2 and CO, d) heating the reaction mixture from steps a) to c), to convert the olefin into an aldehyde.

Description

OPERATING PROCEDURES

General Analysis

[0031] All the preparations that follow were carried out under inert gas using standard Schlenk techniques. The solvents were dried before use over suitable drying agents.

[0032] The products were characterized by NMR spectroscopy. Chemical shifts (δ) are reported in ppm. The .sup.31P NMR signals were referenced as follows: SR.sup.31P=SR.sup.1H.sup.*(BF.sup.31P/BF.sup.1H)=SR.sup.1H.sup.*0.4048.

Synthesis (1)

[0033] ##STR00004##

[0034] In a glovebox, 9 g (0.01 mol) of diorganophosphite dichiorophosphite was weighed into a 250 ml Schlenk flask that had been repeatedly filled and evacuated with inert gas, then discharged and dissolved in 75 ml of dried toluene. In a second 250 ml Schlenk flask that had been repeatedly filled and evacuated with inert gas, 2.2 g (2.1 ml, 0.02 mol) of 3-methylphenol was weighed out and dried at room temperature for 12 hours by means of oil-pump vacuum. 50 ml of dried toluene and 3 ml=2.2 g (0.022 mol) of degassed triethylamine were added while stirring and the solids were dissolved. The dichlorophosphite was added at room temperature to the phenol-triethylamine solution over 1.5 h. The reaction was stirred at room temperature for 15 h, and 1.5 ml (0.011 mol) of triethylamine was added. The reaction mixture was then stirred at 80° C. for another 1.5 h. After cooling to room temperature, the ammonium hydrochloride solids were filtered off using a frit, and the filtrate was concentrated by means of oil-pump vacuum at 40° C. The solids obtained were dried further at room temperature by means of oil-pump vacuum for 15 h. Yield: 76%, purity: 90%.

Synthesis (2) (Comparative Ligand)

[0035] ##STR00005##

[0036] In a glovebox, 9 g (0.01 mol) of diorganophosphite dichlorophosphite was weighed into a 250 ml Schlenk flask that had been repeatedly filled and evacuated with inert gas, then discharged and dissolved in 75 ml of dried toluene. In a second 250 ml Schlenk flask that had been repeatedly filled and evacuated with inert gas, 2.2 g (2.1 ml, 0.02 mol) of 2-methylphenol was weighed out and dried at room temperature for 12 hours by means of oil-pump vacuum. 50 ml of dried toluene and 3 ml=2.2 g (0.022 mol) of degassed triethylamine were added while stirring and the solids were dissolved. The dichlorophosphite was added at room temperature to the phenol-triethylamine solution over 1.5 hours. The reaction mixture was stirred at room temperature for 2 hours and then heated to 80° C. The reaction mixture was stirred at that temperature for 15 hours, and then there were 3 cycles of metered addition of a further 1.5 ml (0.011 mol) of triethylamine and stirring for a further 15 hours. The ammonium hydrochloride was removed by frit, washed with 1×10 ml of dried toluene and concentrated to dryness. The solids were dried at room temperature for 15 hours and stirred with 40 ml of degassed acetonitrile. The precipitated white solids were removed by frit, the Schlenk flask was rinsed through with 2 lots of 10 ml of ACN, dried and then introduced into a glove box. Yield 90%, purity: 95%.

CATALYSIS EXPERIMENTS

[0037] The hydroformylation was carried out in a 16 ml autoclave from HEL Group, Hertfordshire, Great

[0038] Britain, equipped with a pressure-retaining valve, gas flowmeter and sparging stirrer. The n-octene used as substrate (Oxeno GmbH, mixture of octene isomers composed of 1-octene: 3%; cis+trans-2-octene: 49%; cis+trans-3-octene: 29%; cis+trans-4-octene: 16%; structurally isomeric octenes: 3%) was heated under reflux over sodium for several hours and distilled under argon.

[0039] The reaction solutions for the experiments were prepared beforehand under an argon atmosphere. For this, 0.0021 g of Rh(acac)(CO).sub.2 and the corresponding amount of phosphite compound were weighed out and filled with 8.0 ml of toluene. The mass of toluene introduced in each case was determined for the GC analysis. 1.80 g of n-octene (16 mmol) was then added. The prepared solutions were then introduced into the autoclave, which was flushed three times with argon and three times with syngas (Linde; H.sub.2 (99.999%):CO (99.997%)=1:1). The autoclave was then heated to the desired temperature at an overall pressure of 10 bar with stirring (900 rpm). On reaching the reaction temperature, the syngas pressure was increased to 20 bar and the reaction carried out at constant pressure for 4 h. At the end of the reaction time, the autoclave was cooled to room temperature, depressurized while stirring and flushed with argon. 0.5 ml of each reaction mixture was removed at the end of the reaction, diluted with 4 ml of pentane and analysed by gas chromatography: HP 5890 Series II plus, PONA, 50 m×0.2 mm×0.5 μm. Residual olefin and aldehyde were quantitatively determined against the solvent toluene as internal standard.

RESULTS OF THE CATALYSIS EXPERIMENTS

Reaction Conditions:

[0040] [RN]: 120 ppm, L:Rh=1:2, p: 20 bar, T: 120° C.; t: 4 h

TABLE-US-00001 TABLE 1 Hydroformylation of n-octenes Ligand n/iso selectivity in % 1* 77 2 56 *inventive compound

Definition of Selectivity:

[0041] In the hydroformylation there is n/iso selectivity, which is the ratio of linear aldehyde (=n) to branched aldehyde (=iso). The selectivity here in respect of the n-aldehyde signifies that this amount of linear product was formed. The remaining percentages then correspond to the branched isomer. Thus, at a regioselectivity of 50%, n-aldehyde and iso-aldehyde are formed in equal proportions.

[0042] The compound of the invention (1) achieved an increase in n/iso selectivity compared with the comparative ligand (2).

[0043] The experiments carried out demonstrate that the stated object is achieved by the compound of the invention.