Process for preparing hydridocarbonyltris(triphenylphosphine)rhodium(I)

Abstract

The present invention relates to a process for preparing hydridocarbonyltris(triphenylphosphine)rhodium(I), RhH(CO)(PPh.sub.3).sub.3, also referred to hereinafter as Rh-hydrido. An alcoholic suspension of triphenylphosphine is stirred with an Rh(III) chloride precursor at elevated temperature. The Rh(III) chloride precursor used may be rhodium(III) chloride hydrate RhCl.sub.3*xH.sub.2O or rhodium(III) chloride solution H.sub.3[RhCl.sub.6]*(H.sub.2O).sub.n. After cooling, alcoholic alkali metal hydroxide solution is added, and the mixture is stirred for a few hours. Finally, sparging is effected with CO gas and the Rh-hydrido formed is removed. Rh-hydrido can be prepared by this process on the industrial scale with high yields and at very good quality.

Claims

1. A one-step process for preparing RhH(CO)(PPh.sub.3).sub.3, comprising these steps: (a) Preparing an alcoholic suspension of triphenylphosphine PPh.sub.3 in an inerted reaction vessel, (b) Mixing the alcoholic PPh3 suspension with an Rh(III) chloride precursor at a temperature of 30 to 40 C., (c) Stirring the reaction mixture of PPh.sub.3 suspension and Rh(III) chloride precursor at an elevated temperature, wherein stirring is carried out with reflux if the boiling point of the alcohol is below 85 C., or wherein stirring is carried out with the reaction vessel having an internal temperature of 75 C. to 85 C. if the boiling point of the alcohol is 85 C. or higher, (d) Cooling the suspension from step (c) down to 35-50 C., (e) Adding an alcoholic alkali hydroxide solution, (f) Stirring the reaction suspension at 35-50 C., (g) Sparging with CO gas, (h) Separating and optionally washing and drying the hydridocarbonyltris(triphenylphosphine)rhodium(I) complex, RhH(CO)(PPh.sub.3).sub.3.

2. The process according to claim 1, wherein the Cooling of the suspension from step (c) down to 40-50 C., and the Stirring the reaction suspension at 40-50 C.

3. The process according to claim 1, wherein the Rh(III) chloride precursor being selected from rhodium(III) chloride hydrate, RhCl.sub.3*xH.sub.2O, rhodium(III) chloride solution H.sub.3[RhCl.sub.6]*(H.sub.2O).sub.n, aqueous or alcoholic solutions of RhCl.sub.3*xH.sub.2O or H.sub.3[RhCl.sub.6]*(H.sub.2O).sub.n or mixtures thereof.

4. The process according to claim 2, wherein the alcohol for preparing alcoholic solutions of RhCl.sub.3*xH.sub.2O and H.sub.3[RhCl.sub.6]*(H.sub.2O).sub.n and also mixtures of aqueous and alcoholic solutions of RhCl.sub.3*xH.sub.2O and H.sub.3[RhCl.sub.6]*(H.sub.2O).sub.n is selected from the group consisting of methanol, ethanol, n-propanol, 2-propanol and mixtures thereof.

5. The process according to claim 1, wherein the alcohol for preparing the solutions of PPh.sub.3 and the alkali hydroxide solution is selected from the group consisting of methanol, ethanol, n-propanol, 2-propanol and mixtures thereof.

6. The process according to claim 1, wherein the alkali hydroxide is potassium hydroxide.

7. The process according to claim 1, wherein the PPh.sub.3 suspension and the Rh(III) chloride precursor solution are mixed discontinuously in accordance with step (b), wherein the Rh(III) chloride precursor solution is added to the PPh.sub.3 suspension already present.

8. The process according to claim 1, wherein sparging with CO gas is carried out at standard pressure.

9. The process according to claim 1, wherein step (c), the stirring of the reaction mixture of PPh.sub.3 suspension and Rh(III) chloride precursor at an elevated temperature, is carried out for a period of 1.5 to 3 hours.

10. The process according to claim 1, wherein step (f), the stirring of the reaction suspension, is carried out for a period of 1.5 to 3 hours at a temperature of 40-50 C.

11. The process according to claim 1, wherein step (g), sparging with CO gas, is carried out for a period of 2 to 16 hours.

12. The process according to claim 1, wherein in step (h), the end product, RhH(CO)(PPh.sub.3).sub.3, is washed with an alcohol, water or a combination thereof.

13. The process according to claim 1, wherein the alcohol for preparing the alcoholic suspension of triphenylphosphine PPh.sub.3 is selected from the group consisting of methanol, ethanol, n-propanol, 2-propanol and mixtures thereof.

Description

EXEMPLARY EMBODIMENTS

Exemplary Embodiment 1: Preparation of carbonylhydridotris(triphenylphosphine)rhodium(I) from Rh Chloride Solution on the 10 L Scale

(1) Idealized Reaction Equations:
H.sub.3[RhCl.sub.6]*(H.sub.2O).sub.n+4PPh.sub.3.fwdarw.RhCl(PPh.sub.3).sub.3+5HCl+OPPh.sub.3
RhCl(PPh.sub.3).sub.3+KOH+CH.sub.3CH.sub.2OH+PPh.sub.3.fwdarw.RhH(PPh.sub.3).sub.4+KCl+CH.sub.3CHO+H.sub.2O
RhH(PPh.sub.3).sub.4+CO.fwdarw.RhH(CO)(PPh.sub.3).sub.3+PPh.sub.3

(2) A 10 L double-jacketed reactor with a 2-level stirrer, reflux condenser and a gas inlet is inerted with inert gas. With the stirrer revolving at 150 rpm, 6 L ethanol are added. Afterwards, 1.2 kg (4.575 mol) triphenylphosphine (at least 99.5%, manufactured by BASF) are transferred into the reactor. The PPh.sub.3 container is rinsed into the reactor with 50 mL ethanol. The stirrer speed is set to 260 rpm, the cooling water turned on, and the reactor heated to reflux. The mixture is stirred for 30 minutes at reflux. The PPh.sub.3 dissolves completely. The solution is then cooled to T.sub.internal: 35 C., where the PPh.sub.3 can again partially precipitate as a fine powder. Afterwards, 105 g rhodium (1.02 mol) in the form of approx. 525 g aqueous Rh(III) chloride solution (Umicore product no. 68.2565.2720; Rh content approx. 20 wt %) are added. The container with rhodium chloride solution is rinsed into the reactor with 100 mL ethanol. The reaction mixture is then heated once again to reflux (T.sub.internal: 76-78 C.) and maintained at reflux for 2 hours. The result is a red suspension with a fine precipitate.

(3) At the end of the 2 hours, the reaction suspension is cooled to T.sub.internal: 45 C. At this temperature, an ethanolic potassium hydroxide solution (10.3 eq., 10.5 mol potassium hydroxide pellets corresponding to 591 g pure KOH dissolved in 2.2 L ethanol) is added over 0.5 hour by means of a dropping funnel with gas equalization. The KOH-EtOH container and the dropping funnel are rinsed with 0.5 L ethanol into the reactor. The suspension, now yellow, is stirred for 2 hours at T.sub.internal: 45 C. CO gas is then led over the reaction mixture at normal pressure. Sparging is continued for 8 to 16 hours. During this period, the reactor is cooled to T.sub.internal: 20 C.

(4) Following conversion, CO sparging is interrupted and the reactor flushed free of CO with argon or nitrogen. The yellow suspension is discharged inertly onto D4 glass funnel filters and dried by suction. The suspension is then washed with 0.5 L ethanol. After the ethanol is removed by suction at reduced pressure, the filter cake is washed free of chloride with (demineralized) water. The solid substance is then dried in the vacuum drying cabinet at 40 C. until a constant weight is achieved.

(5) The result is approx. 927 g of yellow, crystalline solid with approx. 11.2% rhodium. This is equivalent to a metal-based yield of 99% and a volumetric yield of approx. 104 g/L.

(6) The identity of the product RhH(CO)(PPh.sub.3).sub.3 is determined by .sup.1H- and .sup.31P-NMR spectroscopy in toluene and also by an IR spectrum. Purity is determined by CHN elemental analysis and by quantitative .sup.31P-NMR analysis. The content of rhodium and phosphorus is determined by ICP-OES. The total chlorine content is under 200 ppm (chlorine analyzer).

Exemplary Embodiment 2: Preparation of carbonylhydridotris(triphenylphosphine)rhodium(I) from rhodium(III) Chloride Hydrate

(7) Idealized Reaction Equations:
RhCl.sub.3*xH.sub.2O+4PPh.sub.3.fwdarw.RhCl(PPh.sub.3).sub.3+2HCl+OPPh.sub.3
RhCl(PPh.sub.3).sub.3+KOH+CH.sub.3CH.sub.2OH+PPh.sub.3.fwdarw.RhH(PPh.sub.3).sub.4+KCl+CH.sub.3CHO+H.sub.2O
RhH(PPh.sub.3).sub.4+CO.fwdarw.RhH(CO)(PPh.sub.3).sub.3+PPh.sub.3

(8) A 10 L double-jacketed reactor with a 2-level stirrer, reflux condenser and a gas inlet is inerted with inert gas. With the stirrer revolving at 150 rpm, 6 L ethanol are added. Afterwards, 936 g (3.57 mol) triphenylphosphine (at least 99.5%, manufactured by BASF) are transferred into the reactor. The PPh.sub.3 container is rinsed into the reactor with 50 mL ethanol. The stirrer speed is set to 260 rpm, the cooling water turned on, and the reactor heated to reflux. The mixture is stirred for 30 minutes at reflux. The PPh.sub.3 dissolves completely. The solution is then cooled to T.sub.internal: 35 C., where the PPh.sub.3 can again partially precipitate as a fine powder. Afterwards, 85 g rhodium (0.83 mol) in the form of approx. 224 g rhodium(III) chloride hydrate (Umicore product no. 68.2562.1138; Rh content approx. 38 wt %) are added. The container with rhodium chloride solution is rinsed into the reactor with 50 mL ethanol. The reaction mixture is then heated once again to reflux (T.sub.internal: 76-78 C.) and maintained at reflux for 2 hours. The result is a red suspension with a fine precipitate. At the end of the 2 hours, the reaction suspension is cooled to T.sub.internal: 45 C. At this temperature, an ethanolic potassium hydroxide solution (8.3 eq., 6.9 mol potassium hydroxide pellets corresponding to 386 g pure KOH dissolved in 1.4 L ethanol) is slowly added over 0.5 hour by means of a dropping funnel with gas equalization. The KOH-EtOH container and the dropping funnel are rinsed with 1.4 L ethanol into the reactor. The suspension, now yellow, is stirred for 2 hours at T.sub.internal: 45 C. CO gas is then led over the reaction mixture at normal pressure. Sparging is continued for 8 to 16 hours. During this period, the reactor is cooled to T.sub.internal: 20 C. Conversion with CO can also be carried out under pressure in a pressure reactor. The recommendation here is approx. 0.1 MPa (1 bar) (uninterruptedin other words, readjustment is necessary) for approx. 2-4 h. Afterwards, following pressure relief, the procedure is as follows. Following conversion, CO sparging is interrupted and the reactor flushed free of CO with argon or nitrogen. The yellow suspension is discharged inertly onto D4 glass funnel filters and dried by suction. The suspension is then washed with 0.5 L ethanol. After the ethanol is removed by suction at reduced pressure, the filter cake is washed free of chloride with (demineralized) water. The solid substance is then dried in the vacuum drying cabinet at 40 C. until a constant weight is achieved.

(9) The result is approx. 754 g of yellow, crystalline solid with approx. 11.2% rhodium. This is equivalent to a metal-based yield of 99% and a volumetric yield of approx. 85 g/L.

(10) The identity of the product RhH(CO)(PPh.sub.3).sub.3 is determined by .sup.1H- and .sup.31P-NMR spectroscopy in toluene and also by an IR spectrum. Purity is determined by CHN elemental analysis and by quantitative .sup.31P-NMR analysis. The content of rhodium and phosphorus is determined by ICP-OES. The total chlorine content is under 150 ppm (chlorine analyzer).

Exemplary Embodiment 3: Preparation of carbonylhydridotris(triphenylphosphine)rhodium(I) from Rhodium Chloride Solution on the 1 L Scale in Isopropyl Alcohol (2-propanol)

(11) Idealized Reaction Equations:
H.sub.3[RhCl.sub.6]*(H.sub.2O).sub.n+4PPh.sub.3.fwdarw.RhCl(PPh.sub.3).sub.3+5HCl+OPPh.sub.3
RhCl(PPh.sub.3).sub.3+KOH+C.sub.3H7OH+PPh.sub.3.fwdarw.RhH(PPh.sub.3).sub.4+KCl+C.sub.3H.sub.6O+H.sub.2O
RhH(PPh.sub.3).sub.4+CO.fwdarw.RhH(CO)(PPh.sub.3).sub.3+PPh.sub.3

(12) A 1 L double-jacketed reactor with a 2-level stirrer, reflux condenser and a gas inlet is inerted with inert gas. With the stirrer revolving at 150 rpm, 650 mL isopropyl alcohol are added. Afterwards, 107 g (0.4 mol) triphenylphosphine (at least 99.5%, manufactured by BASF) are transferred into the reactor. The PPh.sub.3 container is rinsed into the reactor with 5 mL isopropyl alcohol. The stirrer speed is set to 260 rpm, the cooling water turned on, and the reactor heated to reflux. The mixture is stirred for 30 minutes at reflux. The PPh.sub.3 dissolves completely. The solution is then cooled to T.sub.internal: 35 C., where the PPh.sub.3 partially precipitates as a fine powder. Afterwards, 9.25 g rhodium (0.090 mol) in the form of approx. 47 g aqueous Rh(III) chloride solution (Umicore product no. 68.2565.2720; Rh content approx. 20 wt %) are added. The container with rhodium chloride solution is rinsed into the reactor with 10 mL isopropyl alcohol. The reaction mixture is then heated once again to reflux (T.sub.internal: 78.5 C.) and maintained at reflux for 2 hours. The result is a red suspension with a fine precipitate.

(13) At the end of the 2 hours, the reaction suspension is cooled to T.sub.internal: 45 C. At this temperature, an ethanolic potassium hydroxide solution (10.3 eq., 1.05 mol potassium hydroxide pellets corresponding to 52 g pure KOH dissolved in 230 mL ethanol) is added over 0.5 hour by means of a dropping funnel with gas equalization. The KOH-EtOH container and the dropping funnel are rinsed with 50 mL ethanol into the reactor. The suspension, now yellow, is stirred for 2 hours at T.sub.internal: 45 C. CO gas is then led over the reaction mixture at normal pressure. Sparging is continued for 8 to 16 hours. During this period, the reactor is cooled to T.sub.internal: 20 C.

(14) Following conversion, CO sparging is interrupted and the reactor flushed free of CO with argon or nitrogen. The yellow suspension is discharged inertly onto D4 glass funnel filters and dried by suction. The suspension is then washed with 50 mL ethanol. After the ethanol is removed by suction at reduced pressure, the filter cake is washed free of chloride with (demineralized) water. The solid substance is then dried in the vacuum drying cabinet at 40 C. until a constant weight is achieved.

(15) The result is approx. 80 g of yellow, crystalline solid with approx. 11.2% rhodium. This is equivalent to a metal-based yield of 97% and a volumetric yield of approx. 80 g/L.

(16) The identity of the product RhH(CO)(PPh.sub.3).sub.3 is determined by .sup.1H- and .sup.31P-NMR spectroscopy in toluene and also by an IR spectrum. Purity is determined by CHN elemental analysis and by quantitative .sup.31P-NMR analysis. The content of rhodium and phosphorus is determined by ICP-OES. The total chlorine content is under 200 ppm (chlorine analyzer).

Exemplary Embodiment 4: Preparation of carbonylhydridotris(triphenylphosphine)rhodium(I) from Rhodium Chloride Solution on the 1 L Scale with Sparging Under Pressure

(17) Idealized Reaction Equations:
H.sub.3[RhCl.sub.6]*(H.sub.2O).sub.n+4PPh.sub.3.fwdarw.RhCl(PPh.sub.3).sub.3+5HCl+OPPh.sub.3
RhCl(PPh.sub.3).sub.3+KOH+CH.sub.3CH.sub.2OH+PPh.sub.3.fwdarw.RhH(PPh.sub.3).sub.4+KCl+CH.sub.3CHO+H.sub.2O
RhH(PPh.sub.3).sub.4+CO.fwdarw.RhH(CO)(PPh.sub.3).sub.3+PPh.sub.3

(18) A 1 L double-jacketed pressure reactor with a 2-level stirrer, reflux condenser and a gas inlet is inerted with inert gas. With the stirrer revolving at 150 rpm, 600 mL ethanol are added. Afterwards, 120 g (0.4575 mol) triphenylphosphine (at least 99.5%, manufactured by BASF) are transferred into the reactor. The PPh.sub.3 container is rinsed into the reactor with 5 mL ethanol. The stirrer speed is set to 260 rpm, the cooling water turned on, and the reactor heated to reflux. The mixture is stirred for 30 minutes at reflux. The PPh.sub.3 dissolves completely. The solution is then cooled to T.sub.internal: 35 C., where the PPh.sub.3 can again partially precipitate as a fine powder. Afterwards, 10.5 g rhodium (0.102 mol) in the form of approx. 52.5 g aqueous Rh(III) chloride solution (Umicore product no. 68.2565.2720; Rh content approx. 20 wt %) are added. The container with rhodium chloride solution is rinsed into the reactor with 10 mL ethanol. The reaction mixture is then heated once again to reflux (T.sub.internal: 76-78 C.) and maintained at reflux for 2 hours. The result is a red suspension with a fine precipitate.

(19) At the end of the 2 hours, the reaction suspension is cooled to T.sub.internal: 45 C. At this temperature, an ethanolic potassium hydroxide solution (10.3 eq., 1.05 mol potassium hydroxide pellets corresponding to 59.1 g pure KOH dissolved in 22:0 mL ethanol) is added over 0.5 hour by means of a dropping funnel with gas equalization. The KOH-EtOH container and the dropping funnel are rinsed with 50 mL ethanol into the reactor. The suspension, now yellow, is stirred for 2 hours at T.sub.internal: 45 C. CO gas at an overpressure of 0.1 MPa (1 bar) is then pressed onto the reaction. The pressure is maintained at 0.1 MPa (1 bar) for 2-4 hours by adjustment of the CO gas. At the end of sparging (but no later than 4 h), the reactor is cooled to T.sub.internal: 20 C. The CO feed is interrupted and pressure released from the reactor. Next, the reactor is flushed free of CO with argon or nitrogen.

(20) The yellow suspension is discharged inertly onto D4 glass funnel filters and dried by suction. The suspension is then washed with 50 mL ethanol. After the ethanol is removed by suction at reduced pressure, the filter cake is washed free of chloride with (demineralized) water. The solid substance is then dried in the vacuum drying cabinet at 40 C. until a constant weight is achieved.

(21) The result is approx. 92.7 g of yellow, crystalline solid with approx. 11.2% rhodium. This is equivalent to a metal-based yield of 99% and a volumetric yield of approx. 104 g/L.

(22) The identity of the product RhH(CO)(PPh.sub.3).sub.3 is determined by .sup.1H- and .sup.31P-NMR spectroscopy in toluene and also by an IR spectrum. Purity is determined by CHN elemental analysis and by quantitative .sup.31P-NMR analysis. The content of rhodium and phosphorus is determined by ICP-OES. The total chlorine content is under 200 ppm (chlorine analyzer).