Diphosphites with an open, 3-methylated outer unit

Abstract

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

Claims

1. A 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. The compound according to claim 1, wherein R.sup.1, R.sup.3 are selected from: —H, —(C.sub.1-C.sub.12)-alkyl.

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

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

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

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

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

9. A ligand-metal complex comprising the compound according to claim 1 and a metal selected from: Rh, Ru, Co or Ir.

10. A 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 or Ir, c) supplying H.sub.2 and CO, and d) heating the reaction mixture from steps a) to c), to convert the olefin into an aldehyde.

Description

CATALYSIS EXPERIMENTS

(1) The hydroformylation was carried out in a 16 ml autoclave from HEL Group, Hertfordshire, Great 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.

(2) 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.

(3) Results of the Catalysis Experiments

(4) Reaction Conditions:

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

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

(7) Definition of Selectivity:

(8) 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.

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

(10) The experiments carried out demonstrate that the stated object is achieved by the compound of the invention.