DE19849297A1 - Water-soluble transition metal compounds used in hydroformylation of olefins to aldehydes contain new type of phosphonated dialkyl-monoaryl-, monoalkyl-diaryl- or triaryl-phosphine ligand - Google Patents

Abstract

Catalysts contain cobalt (Co), nickel (Ni), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir) and/or platinum (Pt) and phosphonylated phosphine (I), consisting of a phosphonylated dialkyl-monoaryl-, monoalkyl-diaryl- or triarylphosphine. Catalysts contain cobalt (Co), nickel (Ni), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir) and/or platinum (Pt) and phosphonylated phosphine (I), consisting of a phosphonylated dialkyl-monoaryl-, monoalkyl-diaryl- or triarylphosphine, of the formula (I): M = a metal with one free valency, hydrogen and/or ammonium; R<1> = branched or linear 2-15 carbon (C) alkylene or aryl; n = 1 or 2; k, m = 0, 1 or 2; k + m = 1 or more; if R<1> = alkyl, m = 1 or more, k = 0 and n = 1; if n = 2, R<1> = alkylene; if n = 1 or more and R<1> = alkylene, m = 0. An Independent claim is also included for the preparation of phosphonylated phosphines (I).

Description

The invention relates to new water-soluble catalysts based on phosphonylated phosphines; Procedure to their Manufacture and its use in water soluble reactions union catalysts.

Water-soluble catalysts are made in two phases sen used, in which the active metal in the aqueous Phase and the products in a second, organic phase to solve. If the water-soluble catalyst is not in the organic phase, is its gentle and effective Separation from the product phase and thus an almost loss free catalyst recycling possible. This principle is used in used in several industrial processes.

The best-known example of the industrial use of water-soluble catalysts is the hydroformylation of propylene. The solubilization of the catalysts (metals of the 8th-10th group of the periodic table) in water is achieved by complex formation with water-soluble ligands. The latter are produced by functionalizing suitable ligands (mostly tertiary phosphines) with hydrophilic functional groups. The most common water-soluble ligands include sulfonated mono- and diphosphines. Nevertheless, in addition to sulfonate groups (-SO ₃ ^- , SO ₃ H), a number of other hydrophilic groups were also introduced into ligands for solubilization. Water-soluble phosphines with carboxylate groups (-COO ^- , -COOH), hydroxyl radicals (-OH), ammonium and phosphonium functions (-NR ₃ ⁺ , -PR ₃ ⁺ ) and with polyether substituents (-O- (CH ₂ -CH ₂ -O) _n -H (Hermann et al .; Angew. Chem. 105 (1993) 1588). Phosphonate-substituted phosphines are far less known (US 4386013, Schull et al., J. Chem. Soc., Chem Commun. (1995) 1487; ibid, Inorg. Chem. 35 (1996) 6717), their use in aqueous two-phase catalysis of carbonylations has only recently been reported (Schull et al., Inorg. Chem. 35 (1996) 6717). The production of individual phosphines which have been derivatized with phosphonic acid groups for the purpose of incorporation in layer structure catalysts is described in DE 196 12 989 A1.

It has been found that the structural properties of the water-soluble ligands strongly influence the activity, selectivity and stability of the catalysts. For example, in the two-phase hydroformylation of propylene by using sulfonated bisphosphines, the activity and regioselectivity can be significantly increased compared to monophosphines such as P (3-C ₆ H ₄ SO ₃ Na) ₃ (TPPTS). In addition, less high ligand-Rh ratios are required for the sulfonated bisphosphines. The solubility of phosphines in water or in organic solvents depends on the degree of sulfonation, but also on the position of the sulfonate groups (Schull et al., Inorg. Chem. 35 (1996) 6717) and thus influences catalytic properties and the retention of Active metals in the aqueous phase.

From the strong influence of aqueous catalysis through the electronic and steric properties of the Ligands give rise to the task of creating new water-soluble catalyzes to develop catalysts with novel ligands. With these should the course of the reaction can be controlled so that the products in desired proportions arise. To high cata- gate concentrations in the aqueous phase and simultaneously to achieve low catalyst losses in the organic phase Chen is a high solubility in water and a low solubility  required in the organic phase.

The present invention fulfills these objectives and relates to novel phosphonylated phosphines as ligands for water-soluble transition metal catalysts. The ligands are of the general formula

described, where M is metals with a free valence and / or hydrogen and / or ammonium, R ^{1 is} branched or unbranched alkylene radicals having 1 to 15, preferably 2 to 12 carbon atoms or aryl or arylene radicals, and n is a value of 1 or 2 assumes. k and m can take integer values from 0 to 2, where k + m ≧ 1. For R ¹ = aryl, m ≧ 1, k = 0 and n = 1. If n = 2, R ^{1 is} an alkylene radical. For n ≧ 1 and R ¹ = alkylene, m = 0.

Ligands with n = 1 and R ¹ = alkylene (ie m = 0) with at least 6 carbon atoms were previously unknown. Their synthesis takes place from a haloalkylphosphonic acid dialkyl. and alkali metal diaryl phosphides, with aprotic solvents such as cyclic ethers, preferably THF, being used. Potassium tert-butoxide ( ^t BuOK) is added in portions to the solution which contains the two starting materials, at temperatures between -40 and 10 ° C., preferably at -5 to 0 ° C., working under a protective gas atmosphere . Potassium halides and excess tBuOK are filtered off from the reaction mixture and the solvent is removed by applying a vacuum. The crude product is treated for 1 h to 24 h, preferably about 2 to 6 h at reflux with an acid-free aqueous hydrohalic acid, preferably with HCl _aq . After removal of the acid in vacuo, treatment with alkali hydroxide is carried out, the pH of the solution being adjusted to about 9.

The likewise new ligands with n = 2 and R ¹ = alkyl (ie m = 0) are prepared analogously, but an arylphosphine is used instead of the diarylphosphine.

Preferred catalysts are those in which m has a value of 0 and R ^{1 represents} branched or unbranched alkylene groups having 2 to 15, preferably 4 to 12, carbon atoms. One or two of these R ¹ radicals are bonded directly to the trivalent phosphorus atom on these preferred catalysts (n = 1 or n = 2). Each of these alkylene groups is preferably substituted with at least one phosphonate group (k ≧ 1).

The ends of branched chains in R ¹ can be substituted with residues such as -OH, -COOH, COONa or be seen with ether functions.

In the above formula, if M is a monovalent metal, so it is selected from Li, Na, K, Rb and Cs. It can also be a divalent metal selected from Mg and Ca, its second valence by another monovalent group is bound.

Ligands with R ¹ = aryl (phosphonylated triarylphosphines) are produced according to the invention from dialkali salts of monoarylphosphines and halogen-substituted arylphosphonic acid dialkylamides, with lithium having proven to be an alkali component and fluorine to be a halogen component. At 0 to 30 ° C., preferably at room temperature, with stirring, a suspension of the dialkali salt in a cyclic ether (preferably in THF) is the halogen-containing phosphonamide within 10 to 180 min. preferably added within 30 to 60 min, the temperature should not exceed 65 ° C. A treatment for several hours at reflux is followed by removal of the alkali halide by filtration, removal of the solvent in vacuo and treatment of the residue with oxygen-free aqueous hydrohalic acid (preferably HCl _aq ). After removing the aqueous acid in vacuo, the residue is washed several times with water to remove the ammonium halides formed. By treating the residue with an aqueous alkali hydroxide solution, an aqueous solution of the ligand (pH approx. 9) is obtained.

Aryl is preferably selected from phenyl, naphthyl and anthracenyl, optionally by methyl and / or Amino groups are substituted.

Yields can be obtained with the above-mentioned syntheses of over 90%.

The invention thus also relates to a process for the preparation of phosphonylated phosphines, which is characterized in that

• a) for the preparation of compounds with R ¹ alkylene having more than 3 carbon atoms, a haloalkylphosphonic acid dialkyl ester of the formula (R ² O) ₂ (O) P) _k ) R ¹ Hal and a mono- or diaryl phosphine used and reacted as starting materials are, wherein R ^{2 represents} alkyl groups with less than 6 carbon atoms and Hal represents a halogen atom, and
• b) for the preparation of compounds with R ¹ = aryl (phosphonylated triarylphosphines) dialkali salts of monoarylphosphines (M ₂ PR ¹ ) and halogen-substituted arylphosphonic dialkyl mides of the formula Hal-C ₆ H ₄ -P (O) (NR ² ₂ ) ₂ are, wherein R ^{2 is} alkyl groups with less than 6 carbon atoms and Hal is a halogen atom.

Preferred catalysts according to the invention are those in Form of rhodium / phosphonate-phosphine catalysts for hydro formylation of monoolefins, non-conjugated polyolefins, Cycloolefins or derivatives of these classes of compounds that are characterized in that they are 2 to 200 per mole of rhodium, preferably 5 to 50 and in particular 10 to 20 mol of the phospho contain nylated phosphines according to claim 1.

The elements of the 8th to 10th come as catalytically active metals. Group of the periodic table in question. Rhodium is particularly suitable for hydroformylation, and rhodium, ruthenium, palladium or iridium are particularly suitable for hydrogenations. The metals can be in the form of mononuclear or polynuclear complexes or as ligand-stabilized colloids. To produce the water-soluble catalysts, metals from the 8th to 10th Group used in elemental form or as a connection. For water-soluble hydroformylation catalysts, rhodium is preferably suitable, which can be used as a finely divided metal, but also as an oxide or salt of mineral or organic acids. From the wide range of salts that can be used, however, the halogen-containing compounds are less useful because of the lower activity. Rh complexes such as (acac) Rh (CO) ₂ and others as well as Rh carbonyl compounds such as. B. Rh ₆ (CO) ₁₆ can be used as a catalyst precursor. It has proven advantageous to use rhodium acetate or the complex salt (acac) Rh (CO) ₂ . The catalyst can be prepared in advance from the aqueous phosphonate phosphine solution and suitable Rh precursors and fed to the reactor. However, it is also possible to produce the water-soluble catalyst composed of Rh component and phosphonated phosphine under the reaction conditions of hydroformylation, ie in the presence of CO and H ₂ . It has proven useful to treat the catalysts for preforming at temperatures between 100 and 130 ° C. and pressures between 10 and 50 bar for periods between 0.5 and 5 hours in the absence of the olefinic substrate with synthesis gas. In the catalysts, the molar ligand-metal ratios (n _ligand : n _metal ) can be set between 0.5: 1 and 200: 1, preferably between 2: 1 and 50: 1. The concentration of rhodium in the aqueous phase is between 10 and 4000 ppm by weight, based on the mass of the solution, preferably from 100 to 500 ppm by weight. The volume ratio of CO and H ₂ can be varied over a wide range from 1:10 to 10: 1. Usually CO-H ₂ mixtures with a composition of about 1: 1 are used. The temperature range for hydroformylations with said catalysts is between 50 and 150 ° C, preferably 80 to 140 ° C and in particular the temperature range between 90 and 125 ° C. It has proven to be advantageous to keep the proportion of the organic phase in the total volume small. Volume ratios (organic _phase : _{aqueous phase} ) of less than 0.25 are advantageous.

Hydroformylation in the presence of phosphonylated Li ganden in aqueous two-phase systems can both in paragraph operation as well as continuously.

By selecting suitable phosphonylated phosphines according to the invention and carefully setting the ligand: Rh ratios, both high proportions of n-butyraldehyde and mixtures of n- and iso-butyraldehyde in a molar ratio of about 1 can be obtained in the hydroformylation of propylene at high activities , 2 received (see Example 4). It can be used to react flexibly to changing needs for n- and iso-aldehydes. All branched or unbranched α-olefins having up to 20 carbon atoms can be used as substrates. In particular Rh catalysts which contain phosphonylated phosphines of the formula (M ₂ O ₃ P) _k R ¹ PPh ₂ , in which k = 1 or k = 2 and R ^{1 is} branched and unbranched alkylene radicals having 8 to 16 carbon atoms, are very suitable for the hydroformylation of long-chain olefins in aqueous two-phase systems (see Example 5). The field of application of the novel water-soluble catalysts is not limited to aqueous two-phase catalysis. Palladium catalysts which contain the phosphonylated phosphines according to the invention are also suitable for homogeneously catalyzed reactions in water, for example for the reduction of hydroxymethyl groups to methyl groups, which proceeds very selectively with the new catalysts even on molecules with CC double bonds and aldehyde groups .

The invention is illustrated below by examples are explained.

example 1 Preparation of Na ₂ O ₃ P- (CH ₂ ) ₁₂ -PPh ₂

0.1 mol of diethyl 12-bromo-dodecylphosphonate ((C ₂ H ₂ O) ₂ (O) P- (CH ₂ ) ₁₂ -Br) and 0.1 mol of diphenylphosphine (HPPh ₂ ) are added to 250 ml of tetrahydrofuran (THF). 0.11 mol of potassium tert-butoxide ( ^t BuOK) are added in portions to the solution, which has been cooled to 0 ° C. in an ice bath, under a protective gas atmosphere. Then it is filtered off from the resulting KBr and excess ^t BuoK, THF is removed in vacuo and the colorless oil obtained is heated under reflux under Ar for 4 hours with 250 ml of oxygen-free concentrated aqueous HCl solution. After removing the HCl solution in vacuo, a solution with a pH of about 9 is adjusted by adding a 20 to 30% NaOH solution. This can be used directly as a stock solution for catalyst production.
Yield of Ph ₂ P- (CH ₂ ) ₁₂ -PO ₃ Na ₂ : 90% (based on HPPh ₂ .

Example 2 Preparation of PhP (3-C ₆ H ₄ PO ₃ Na ₂ ) ₂

To 0.1 mol Dilithiumphenylphosphid (Li ₂ PPh) in 300 ml of THF over 30 minutes with stirring and gentle stream of argon at room temperature 0.21 mol m-Fluorphenylphosphon oic acid diethylamide (3-FC ₆ H ₄ -P (O) (N ( C ₂ H ₅ ) ₂ ) ₂ ) given, the temperature rising to 55 ° C, which can be seen from the slight reflux of the THF. During the subsequent 5-hour reflux treatment, the deep red solution discolored. After the solution has cooled, lithium fluoride is sedimented by adding 10 ml of water and the solution is decanted from the precipitate which has precipitated out. After removal of the THF in vacuo, a honey-colored residue remains, which is heated to boiling for 1 hour with 200 ml of an approximately 20% aqueous oxygen-free HCl. The hydrochloric acid is removed in vacuo and the solid mass obtained is shaken out with 150 ml of deoxygenated water. This removes excess diethylammonium hydrochloride and the m-fluorophenylphosphonic acid formed from the excess substrate. The residue obtained after decanting the aqueous phase is washed twice with 20 ml of water. With NaOH, a stock solution of Na-phosphonate-phosphine with a pH of about 9 is prepared.
Yield of PhP (3-C ₆ H ₄ PO ₃ Na ₂ ) ₂ : 90%

Example 3 Preparation of an aqueous catalyst solution

0.0194 mmol (acac) Rh (CO) ₂ and 2 ml deoxygenated water are added to 0.78 ml of a 0.25 M stock solution of the phosphonate phosphine described in Example 1, stirred under argon. From the precursor compound, which is hardly soluble in water, a yellow catalyst solution is formed within 2 hours, the concentration of which by filling with water to a volume of 20 ml to 9.7. 10 ^-4 mol / l Rh is set.

Example 4 Hydroformylation of propylene

The procedure of Example 3 is followed, and 10 ml of a catalyst solution containing 400 ppm by weight of Rh and 5 ml of nonane (internal standard) are added to a 100 ml autoclave. After triple application of synthesis gas (30 bar) and decompression, propylene is added to the autoclave until a pressure of 8.5 bar is reached. A pressure of 20 bar is set with synthesis gas (CO / H ₂ = 1/1), which is adjusted after the autoclave has been heated to the reaction temperature of 120 ° C. using a pressure reducer to 30 bar and is kept constant over the reaction time of 2 hours . The reaction mixture is stirred at the rate of 600 revolutions / minute from the start of heating the automobile.

After 2 hours, the autoclave is cooled in an ice bath and turned on finally the organic phase is analyzed. Test results with selected catalysts are given in Table 1.

Example 5 Hydroformylation of oct-1-ene

In a 100 ml autoclave flushed with argon, 20 ml of a catalyst solution containing 100 ppm by weight of Rh (see Example 3) are introduced and treated for ₂ hours at 120 ° C. and 30 bar synthesis gas (CO / H ₂ = 1/1) (Catalyst preforming). After cooling to room temperature and relaxing, 5 ml of oct-1-ene are added in the absence of air. After flushing three times with synthesis gas, a pressure of 20 bar is set and heated up. When the reaction temperature of 120 ° C is reached, a pressure of 30 bar is set via a pressure reducer and kept constant over the reaction time of 4 hours. The reaction mixture is from the beginning of the heating of the autoclave at a speed of 600 rev / min. touched. After 4 h, the autoclave is cooled in an ice bath and then the organic phase is analyzed. Test results with selected catalysts are given in Table 2.

Claims (18)

1. Catalysts which have one or more elements from the group Co, Ni, Ru, Rh, Pd, Os, Ir and Pt and phosphonylated phosphines of the formula
included, where
M represents metals with a free valence and / or hydrogen and / or ammonium,
R ¹ represents branched or unbranched alkylene radicals having 2 to 15 carbon atoms or aryl radicals,
n has a value of 1 or 2,
k and m represent integer values from 0 to 2, where k + m ≧ 1 applies,
for R ¹ = Aryl applies m ≧ 1, k = 0 and n = 1,
R ¹ represents an alkylene radical if n = 2,
and m represents the value 0 when n ≧ 1 and R ^{1 is} an alkylene radical. 2. Catalysts according to claim 1, characterized in that m has a value of 0 and that R ^{1 represents} branched or unbranched alkylene groups with 2 to 15, preferably with 4 to 12 carbon atoms and that one or two of these radicals R ¹ on the trivalent phosphorus atom are directly bonded so that n = 1 or n = 2 and that each of these alkylene groups is substituted with at least one phosphonate group, so that k ≧ 1. 3. Catalysts according to claim 2, characterized in that the ends of branched chains in R ¹ are substituted with radicals such as -OH, -COOH, COONa, or ether functions. 4. Catalysts according to claim 1, characterized in that M is a monovalent metal selected from Li, Na, R, Rb and Cs, or a divalent metal selected from Mg and Ca, whose second valence by a monovalent group is bound. 5. Catalysts according to claim 1, characterized in that Aryl is selected from phenyl, naphthyl and anthracenyl, which, if necessary, by methyl and / or amino groups sub are established. 6. Catalysts according to claim 1 in the form of rhodium / phospho nat-phosphine catalysts for the hydroformylation of mono olefin-non-conjugated polyolefins, cycloolefins or Derivatives of these classes of compounds, characterized in that that they are 2 to 200 per mol of rhodium, preferably 5 to 50 and ins special 1.0 to 20 mol of the phosphonylated phosphines after Claim 1 included. 7. A process for the preparation of phosphonylated phosphines according to claim 1, characterized in that

• a) a haloalkylphosphonic acid dialkyl ester of the formula (R ² O) ₂ (O) P) _k ) R ¹ Hal and a mono- or diaryl phosphine are used and reacted as starting materials for the preparation of compounds with R ¹ = alkylene having more than 3 carbon atoms , wherein R ^{2 stands} for alkyl groups with less than 6 carbon atoms and Hal for a halogen atom, and
• b) for the preparation of compounds with R ¹ = aryl (phosphonylated triarylphosphines) dialkali salts of monoarylphosphines of the formula M ₂ PR ¹ , in which M is lithium, sodium or potassium, and halogen-substituted arylphosphonic dialkylamides of the formula Hal-C ₆ H ₄ -P ( O) (NR ² ₂ ) _{2 are} implemented, where R ^{2 represents} alkyl groups with less than 6 carbon atoms and Hal represents a halogen atom.

8. The method according to claim 7a, characterized in that the two starting materials in aprotic solvents, preferably are dissolved in tetrahydrofuran. 9. The method according to claim 7a, characterized in that to the raw materials in a protective gas atmosphere potassium tert.- butylate is added. 10. The method according to claim 7a, characterized in that the reaction at temperatures between -40 and 10 ° C, before preferably at -5 to 0 ° C. 11. The method according to claim 7b, characterized in that Lithium as the alkali component and fluorine as the halogen component be used. 12. The method according to claim 7b, characterized in that the reaction is carried out at temperatures between 0 and 70 ° C. becomes. 13. Process for the preparation of aldehydes by reaction of monoolefins non-conjugated polyolefins, cycloolefins or derivatives of these classes of compounds with carbon monoxide and Hydrogen at temperatures between 50 and 150 ° C and pressure between 1 and 200 bar with water-soluble rhodium catalyze Sators, characterized in that the catalyst solution phosphonylated phosphines according to claim 1. 14. The method according to claim 13, characterized in that each mol of rhodium 2 to 200, preferably 5 to 50 and in particular 10 up to 20 mol of the phosphonylated phosphines are used. 15. The method according to claim 14, characterized in that the rhodium concentration of the aqueous catalyst solution 10 to 4000, preferably 200 to 1000 ppm by weight, based on the Solution.   16. The method according to any one of claims 13 to 15, characterized ge indicates that the reaction at temperatures between 50 and 150 ° C, preferably at 80 to 140 ° C and especially at 100 to 130 ° C takes place. 17. The method according to any one of claims 13 to 16, characterized ge indicates that the conversion at pressures between 1 and 200 bar, preferably at 10 to 120 bar and in particular at 30 up to 70 bar. 18. The method according to any one of claims 13 to 17, characterized ge indicates that olefins or olefin derivatives with 2 to 20, preferably with 2 to 16 and in particular with 2 to 14 Koh lenstoffatomen be implemented.