CN113289695B

CN113289695B - Method for recovering hydroformylation catalyst

Info

Publication number: CN113289695B
Application number: CN202110684091.5A
Authority: CN
Inventors: 黄少峰; 马岩龙; 任亚鹏; 许振成; 黎源
Original assignee: Wanhua Chemical Group Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd
Priority date: 2021-06-21
Filing date: 2021-06-21
Publication date: 2022-07-12
Anticipated expiration: 2041-06-21
Also published as: CN113289695A

Abstract

The invention relates to a method for recovering an olefin hydroformylation catalyst, which comprises the following steps: after the hydroformylation reaction is finished, adding a strong oxidant, water-resistant Lewis acid and a complexing agent aqueous solution into a reaction solution to extract a catalyst, separating oil and water phases, separating aldehyde and/or alcohol products from an oil phase, pre-carbonylating the water phase in the presence of synthesis gas and olefin under the conditions of certain temperature and pressure, separating an organic phase containing the catalyst and a water phase containing the complexing agent from the pre-carbonylated product, returning the organic phase to the hydroformylation reaction step, and reusing the water phase. The method for separating the hydroformylation catalyst has the advantages of high recovery rate, simple process and obvious economic advantage.

Description

Method for recovering hydroformylation catalyst

Technical Field

The invention relates to a method for recovering an olefin hydroformylation catalyst.

Technical Field

In the industrial cobalt or rhodium catalyzed olefin hydroformylation reaction, the separation process of the aldol product and the catalyst is often accompanied with the precipitation and inactivation of cobalt or rhodium, and the catalyst is difficult to apply.

The separation and recovery of the cobalt catalyst are mainly carried out industrially by (1) Kuhlmann method. That is, Na is added to the reaction mixture₂CO₃Aqueous solution, HCo (CO)₄Catalyst and Na₂CO₃Conversion by reaction to NaCo (CO)₄(ii) a The organic phase containing the product is brought into contact with a liquid containing NaCo (CO)₄After separation of the aqueous phase of (A), with H₂SO₄Treating the aqueous phase to remove NaCo (CO)₄Regeneration to HCo (CO)₄(ii) a Extraction of HCo (CO) from the starting olefin₄And returning to the reactor to achieve the recovery and recycling of the cobalt catalyst. (2) The redox method adopted by BASF and the like. Introducing oxygen and carboxylic acid (formic acid or acetic acid) into the crude hydroformylation product to oxidize cobalt with a valence of-1 or 0 into water-soluble cobalt carboxylate; after separating the organic phase containing the product from the aqueous phase containing the cobalt carboxylate, the cobalt carboxylate solution is concentrated and used as starting material for the preparation of the catalyst. The two methods have complex process and low catalyst recovery rate, both need corrosive acid-base media, are easy to generate simple substance cobalt precipitate and block pipelines, and the Kuhlmann method also needs to be carried out under the condition of high pressure of 20Mpa, and has high requirements on equipment.

The main recovery methods of the rhodium catalyst comprise a pyrogenic process, a wet process and other processes. The pyrogenic process is characterized in that rhodium-containing organic waste is subjected to high-temperature roasting treatment under certain conditions to enrich rhodium in solid matters, and then the enriched matters are subjected to subsequent refining and purification to realize recovery of rhodium. The wet process mainly comprises the steps of carrying out corresponding wet treatment on rhodium-containing waste to precipitate or enrich rhodium in a solution, and then carrying out refining, purification and recovery, wherein the wet process mainly comprises a digestion method, an extraction method, a sulfide precipitation method, an adsorption method and the like. In the practical application process, various processes have some problems to different degrees, such as serious volatilization loss of rhodium, generation of toxic and harmful gas, harsh process conditions, high requirements on equipment and devices and the like, and the industrial application of the processes is seriously influenced.

Therefore, the development of a large-scale and industrialized process which is simple and safe in operation, high in recovery rate, wide in application range, green and environment-friendly is needed, the recycling of the catalyst is realized, and the environmental pollution is reduced.

Disclosure of Invention

The invention aims to provide a method for recovering an olefin hydroformylation catalyst, which can be used for recovering the hydroformylation catalyst simply, safely and efficiently, has mild operation conditions and reduces the discharge of three wastes.

In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows:

a method for recovering an olefin hydroformylation catalyst, the method comprising the steps of:

(1) after the hydroformylation reaction is finished, adding a strong oxidizing agent, water-resistant Lewis acid and a water solution of a complexing agent into a reaction solution for extracting the catalyst, wherein the water-resistant Lewis acid is trifluoromethanesulfonate of lanthanide, and the complexing agent is selected from one or more of hydroxycarboxylic acid and salts thereof, polyphosphoric acid and salts thereof, amino acid and salts thereof, hydroxyamino carboxylic acid and salts thereof, and methylene phosphonate and salts thereof;

(2) separating the extracted oil phase and the water phase, separating aldehyde and/or alcohol products from the oil phase, and pre-carbonylating the water phase at a certain temperature and pressure in the presence of synthesis gas and olefin;

(3) separating the products of the pre-carbonylation into an organic phase containing the catalyst and an aqueous phase containing the water-resistant Lewis acid, the complexing agent, returning the organic phase to the hydroformylation reaction step, and reusing the aqueous phase.

In the method of the present invention, the strong oxidant is ozone and/or superoxide, preferably ozone and/or hydrogen superoxide. The amount of the strong oxidant added is 1 to 100 percent, preferably 10 to 50 percent of the total molar amount of the catalyst in the hydroformylation reaction liquid. If the catalyst is cobalt iso-octoate, it is calculated on the cobalt molar basis.

In the method of the invention, the lanthanide used is one or more of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb, preferably one or more of La, Ce, Sm and Yb. The addition amount of the water-resistant Lewis acid is 10 to 300 percent of the total molar amount of the catalyst in the hydroformylation reaction liquid, and preferably 50 to 150 percent.

In the method of the present invention, the complexing agent salt is selected from one of metal salts, preferably sodium salt and/or potassium salt. The addition amount of the complexing agent is more than 1 time, preferably 1 time to 5 times of the molar amount of the hydroformylation catalyst, the extraction treatment time is 0.1 to 2 hours, preferably 0.5 to 1 hour, and the temperature is 20 to 100 ℃, preferably 60 to 80 ℃.

The complexing agent is preferably one or more of citrate, tartrate, hexametaphosphate, pyrophosphate, tripolyphosphate, methylglycine diacetate, glutamic acid diacetate, hydroxyethylenediaminetetraacetate, ethylene glycol bis (beta-diaminoethyl) ethyl ether-N, N, N ', N' -tetraacetate, dihydroxyethyl glycinate, aminodimethylidene phosphonate, aminotrimethylidene phosphonate, ethylenediamine tetramethylene phosphonate, diethylenetriamine pentamethylene phosphonate and hydroxyethylethylenediamine trimethylene phosphonate.

In the invention, the temperature of the pre-carbonylation reaction is 50-200 ℃, the pressure is 2-100Mpa, the addition amount of the olefin is 1-1000 times of the molar amount of the hydroformylation catalyst, the consumption amount of the synthesis gas is more than 1 time of the molar amount of the olefin, and the reaction time is 0.5-10 h.

In the invention, the hydroformylation reaction liquid is generated by the catalytic reaction of olefin and synthesis gas at the temperature of 50-200 ℃ and the pressure of 2-100 Mpa. The olefin is selected from C2-C20 olefin. The catalyst is selected from salts of metals, preferably existing in the forms of acetate, isooctanoate, naphthenate and acetylacetonate, the metal is one or more of Rh, Co, Ir, Ru, Os, Fe, Pd or Pt, preferably cobalt or rhodium, the catalyst can contain a ligand, and the reaction can be regulated by adding the ligand. The ligand is selected from one or more of phosphorus-containing ligand and nitrogen-containing ligand; wherein the phosphorus-containing ligand is selected from one or more of alkyl phosphorus such as tributyl phosphine, triphenyl phosphine, tricyclohexyl phosphine, 4, 5-bis diphenyl phosphine-9, 9-dimethyl xanthene, alkyl phosphite such as triethyl phosphite, tributyl phosphite, triisooctyl phosphite and triphenyl phosphite; the nitrogen-containing ligand is selected from one or more of pyridine, trimethylamine and triethylamine; the dosage of the ligand is 1-1000 times of the mole number of the catalytic metal in terms of the mole number of phosphorus atoms or nitrogen atoms.

The reaction time of the hydroformylation reaction is 0.2-20 h.

Hydrogen and carbon monoxide (H) in syngas₂CO) in a molar ratio of 1: 1-2: 1, and controlling the reaction pressure to be 2-100Mpa through the feeding amount.

Preferably, the hydroformylation catalyst is 0.0001 to 1 percent of the mass of the olefin based on the mass of the catalytic metal in the hydroformylation catalyst.

The olefin is preferably a C2 to C14 olefin, including but not limited to ethylene, propylene, butene, pentene, hexene, heptene, octene, and mixed olefins of each with one or more of the respective isomers. The olefin may also be in the form of an olefin oligomer, such as a trimer, tetramer of olefins.

Hydroxycarboxylic acids and salts thereof, polyphosphoric acids and salts thereof, amino acids and salts thereof, hydroxyamino carboxylic acids and salts thereof, methylene phosphonate and salts thereof are strong complexing agents and can perform strong complexing reaction with metal catalysts, so that the catalysts are extracted from an oil phase to a water phase. The complexing agents have short complexing time and high complexing efficiency, the complexing ability is not reduced after continuous repeated application, and the effective adsorption capacity can reach one to several times of the molar quantity of the complexing agents. It should be noted that, the metal catalyst is reduced to zero valence state during the hydroformylation reaction, and some metal clusters are formed, and these metals are difficult to be directly complexed and separated, the zero valence metal can be oxidized to high valence ion state by adding ozone or superoxide, and the metal clusters are decomposed into metal ions, so that the catalyst can be recovered by the complexation and separation method, and the activity of the recovered metal catalyst can be kept stable during the hydroformylation process by the decomposition of the clusters. Compared with common oxygen or peroxide, the ozone or superoxide has stronger oxidizing ability and higher catalytic activity, so the oxidation reaction time is greatly shortened, the oxidation of metal is more thorough, the recovery efficiency of the catalyst is high, and the activity is stable. The addition of a water-resistant lewis acid such as the triflate of a lanthanide can promote the decomposition of the cluster in an acidic environment, making the oxidation process more rapid and efficient. Through strong oxidation, acidification and complexation, the recovery rate of the catalyst can reach more than 99.9 percent.

Taking the example of absorbing cobalt by using the disodium methylglycinediacetate as a complexing agent, the reaction is as follows:

the pressure in the present invention is a gauge pressure.

Compared with the prior art, the method can simply, safely and high-yield recover the hydroformylation catalyst, has mild operation condition and reduces the discharge of three wastes.

The specific implementation mode is as follows:

the present invention will now be described in further detail with reference to examples, but the scope of the present invention is not limited to such examples.

The analytical instruments and methods used in the examples are as follows:

gas chromatograph: agilent-7820;

gas chromatographic column: 0.25mm 30m DB-5 capillary column, detector FID, vaporizer temperature 280 ℃, column box temperature 280 ℃, FID detector temperature 300 ℃, argon carrier flow 2.1mL/min, hydrogen flow 30mL/min, air flow 400mL/min, and sample injection 1.0 μ L. The conversion of the alkene and the selectivity of the product were calculated using area normalization. Temperature rising procedure: preheating to 40 deg.C, holding for 5min, and heating at 15 deg.C/min from 40 deg.C to 280 deg.C, and holding for 2 min.

Ion chromatography: agilent 720-OES

Example 1

(1) Preparation of hydroformylation reaction solution: adding 500g of tetrapropylene and 0.5g of cobalt isooctanoate (cobalt content is 12%) into a 1L autoclave, replacing the autoclave with nitrogen for three times, pressurizing synthetic gas (the molar ratio of hydrogen to carbon monoxide is 1: 1, the same below) to 20Mpa, stirring at the rotating speed of 1000r/min, reacting at 150 ℃ for 5 hours, discharging the synthetic gas after the reaction is finished to obtain hydroformylation reaction liquid, analyzing the conversion rate by gas chromatography to be 82%, and the selectivity to be 81%.

(2) Removing the catalyst: adding 10g of a sodium methylglycinediacetate saline solution (271g/mol) with the mass concentration of 20% into a reaction kettle, adding 0.06g of lanthanum trifluoromethanesulfonate (586g/mol), introducing 2ml of ozone (standard condition), stirring for 2h at 20 ℃, standing for layering, separating an upper oil phase and a lower water phase, and measuring the cobalt content of the oil phase by using ICP (inductively coupled plasma), wherein the cobalt content is less than 1 ppm.

(3) Catalyst regeneration: adding the lower water phase into a 100ml reaction kettle, adding 10g of tetrapropylene, reacting for 1h under the conditions of synthesis gas pressure of 20Mpa, stirring speed of 1000r/min and 150 ℃, and separating the oil phase catalyst and the water phase complexing agent.

(4) The oil phase catalyst, the water phase lanthanum triflate and the complexing agent are used, the steps (1) to (3) are repeated, the catalyst is continuously applied for 10 times, and the conversion rate, the selectivity and the cobalt content in the oil phase are as follows:

	conversion (%)	Selectivity (%)	Cobalt content (ppm)
				For the first time	82	81	＜1ppm
For the second time	83	81	＜1ppm
				For the third time	83	82	＜1ppm
For the fourth time	82	82	＜1ppm
				For the fifth use	83	82	＜1ppm
For the sixth time	84	80	＜1ppm
				For the seventh application	83	82	＜1ppm
For the eighth application	81	80	＜1ppm
				For the ninth application	81	80	＜1ppm
For the tenth application	80	80	＜1ppm

Example 2

(1) Preparation of hydroformylation reaction solution: adding 500g of diisobutylene and 0.05g of rhodium acetate (161.95g/mol) into a 1L high-pressure kettle, replacing the reaction kettle with nitrogen for three times, pressurizing synthetic gas to 20Mpa, stirring at the rotating speed of 1000r/min, reacting at 120 ℃ for 4 hours, discharging the synthetic gas after the reaction is finished to obtain hydroformylation reaction liquid, and analyzing the conversion rate by gas chromatography to be 95% and the selectivity to be 97%.

(2) Removing the catalyst: adding 10g of 1% amino trimethylene sodium phosphonate (299g/mol) solution with mass concentration into a reaction kettle, adding 0.57 ytterbium trifluoromethanesulfonate (620g/mol), adding 0.005g of hydrogen peroxide, stirring for 1h at 100 ℃, standing for layering, separating an upper oil phase and a lower water phase, and measuring the cobalt content of the oil phase by using ICP (inductively coupled plasma), wherein the cobalt content is less than 1 ppm.

(3) Catalyst regeneration: adding the lower water phase into a 100ml reaction kettle, adding 10g of diisobutylene, reacting for 1h under the conditions of synthesis gas pressure of 20Mpa, stirring speed of 1000r/min and 150 ℃, separating an oil phase catalyst, repeating the reaction in the step (1), and analyzing the conversion rate by gas chromatography to be 94% and the selectivity to be 96%.

Example 3

(1) Preparation of hydroformylation reaction solution: adding 500g of triisobutene and 0.05g of rhodium octanoate (778.6g/mol) into a 1L autoclave, replacing the autoclave with nitrogen for three times, pressurizing synthetic gas to 20Mpa, stirring at the rotating speed of 1000r/min, reacting at 180 ℃ for 7 hours, discharging the synthetic gas after the reaction is finished to obtain hydroformylation reaction liquid, analyzing the conversion rate by gas chromatography to be 85 percent, and the selectivity to be 72 percent.

(2) Removing the catalyst: adding 10g of sodium citrate (258g/mol) aqueous solution with the mass concentration of 2% into a reaction kettle, adding 0.02g of ytterbium trifluoromethanesulfonate, introducing 0.29ml of ozone (standard condition), stirring at 60 ℃ for 0.5h, standing for layering, separating an upper oil phase and a lower water phase, and measuring the cobalt content of the oil phase by using ICP (inductively coupled plasma), wherein the cobalt content is less than 1 ppm.

(3) Catalyst regeneration: adding the lower-layer water phase into a 100ml reaction kettle, adding 10g of triisobutene, reacting for 1h under the conditions of synthesis gas pressure of 20Mpa, stirring speed of 1000r/min and 150 ℃, separating an oil-phase catalyst, repeating the reaction in the step (1), and analyzing the conversion rate and the selectivity by gas chromatography to be 86% and 73%.

Example 4

(1) Preparation of hydroformylation reaction solution: adding 500g of triisobutene and 0.05g of rhodium octoate into a 1L autoclave, replacing the autoclave with nitrogen for three times, pressurizing synthetic gas to 20Mpa, stirring at the rotating speed of 1000r/min, reacting at 180 ℃ for 7 hours, discharging the synthetic gas after the reaction is finished to obtain hydroformylation reaction liquid, and analyzing the conversion rate and the selectivity by gas chromatography to be 85% and 72%.

(2) Removing the catalyst: adding 10g of 5% hydroxyethylenediaminetetraacetic acid sodium salt (380g/mol) water solution with mass concentration into a reaction kettle, adding 0.056g of lanthanum trifluoromethanesulfonate, introducing 1.45ml of ozone (standard condition), stirring at 80 ℃ for 0.1h, standing for layering, separating an upper oil phase and a lower water phase, and measuring the cobalt content of the oil phase by using ICP (inductively coupled plasma), wherein the cobalt content is less than 1 ppm.

(3) Catalyst regeneration: adding the lower-layer water phase into a 100ml reaction kettle, adding 10g of triisobutene, reacting for 1h under the conditions of synthesis gas pressure of 20Mpa, stirring speed of 1000r/min and 150 ℃, separating an oil-phase catalyst, repeating the reaction in the step (1), and analyzing the conversion rate by gas chromatography with the selectivity of 73 percent at 84 percent.

Example 5

(1) Preparation of hydroformylation reaction solution: adding 500g of triisobutene and 0.5g of cobalt isooctanoate (cobalt content is 12%) into a 1L high-pressure kettle, replacing the reaction kettle with nitrogen for three times, pressurizing synthetic gas to 20Mpa, stirring at 1000r/min, reacting at 160 ℃ for 4 hours, discharging the synthetic gas after the reaction is finished to obtain hydroformylation reaction liquid, and analyzing the conversion rate and the selectivity by gas chromatography to be 83% and 80%.

(2) Removing the catalyst: adding 10g of dihydroxyethyl glycine sodium salt (185g/mol) aqueous solution with the mass concentration of 7% into a reaction kettle, adding 0.06g of lanthanum trifluoromethanesulfonate (586g/mol), introducing 2ml of ozone (standard condition), stirring for 2h at 20 ℃, standing for layering, separating an upper oil phase and a lower water phase, and measuring the cobalt content of the oil phase by using ICP (inductively coupled plasma), wherein the cobalt content is less than 1 ppm.

(3) Catalyst regeneration: adding the lower-layer water phase into a 100ml reaction kettle, adding 10g of triisobutene, reacting for 1h under the conditions of synthesis gas pressure of 20Mpa, stirring speed of 1000r/min and 160 ℃, separating an oil-phase catalyst, repeating the reaction in the step (1), and analyzing the conversion rate and the selectivity by gas chromatography to be 82% and 81%.

Comparative example 1

The conditions of example 4 were adopted, Lewis acid lanthanum triflate was not added, the oxidizing agent was changed from ozone to oxygen, the remaining conditions were the same as those of example 4, and in step (2), cobalt content was measured by ICP, and cobalt content was 10 ppm. The reaction in step (1) was repeated with a conversion of 80% and a selectivity of 79% by gas chromatography.

Comparative example 2: (existing catalyst recovery scheme)

The hydroformylation reaction solution prepared in the step (1) in the example 4 is added into a 1L three-neck flask, the pressure is reduced to 3Kpa, the distillation separation is carried out at 80-180 ℃, the triisobutene, the tridecanal and the tridecanol are collected as raw materials, and residual heavy components are left in a tower bottom. And after the rectification is finished, cooling to room temperature, burning the heavy component waste liquid, collecting solid residues, adding 10g of potassium bisulfate, heating to 500-600 ℃, reacting for 2h, cooling, adding 2mol/L hydrochloric acid, and filtering to obtain a rhodium sulfate catalyst solution, wherein the recovery rate of rhodium is 95%.

Claims

1. A method for recovering an olefin hydroformylation catalyst, the method comprising the steps of:

(1) after the hydroformylation reaction is finished, adding a strong oxidizing agent, water-resistant Lewis acid and a water solution of a complexing agent into a reaction solution for extracting the catalyst, wherein the water-resistant Lewis acid is trifluoromethanesulfonate of lanthanide, and the complexing agent is selected from one or more of hydroxycarboxylic acid and salts thereof, polyphosphoric acid and salts thereof, amino acid and salts thereof, hydroxyamino carboxylic acid and salts thereof, and methylene phosphonate and salts thereof; the strong oxidant is ozone and/or superoxide hydrogen;

(2) separating the extracted oil phase from the water phase, separating aldehyde and/or alcohol product from the oil phase, and pre-carbonylating the water phase at certain temperature and pressure in the presence of synthetic gas and olefin;

(3) separating the products of the pre-carbonylation into an organic phase containing the catalyst and an aqueous phase containing the water-resistant Lewis acid and the complexing agent, returning the organic phase to the step of the hydroformylation reaction, and reusing the aqueous phase.

2. The method according to claim 1, wherein the amount of the strong oxidant added is 1 to 100% of the total molar amount of the catalyst in the reaction solution after the hydroformylation reaction is completed.

3. The method according to claim 1, wherein the amount of the strong oxidant added is 10% to 50% of the total molar amount of the catalyst in the reaction solution after the hydroformylation reaction is completed.

4. A method according to any of claims 1-3, characterized in that the lanthanide used is one or more of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb.

5. The method according to claim 4, wherein the lanthanide used is one or more of La, Ce, Sm and Yb.

6. The method according to any one of claims 1 to 3, wherein the water-resistant Lewis acid is added in an amount of 10 to 300% based on the total molar amount of the catalyst in the hydroformylation reaction solution.

7. The method of claim 6, wherein the water-tolerant Lewis acid is added in an amount of 50% to 150% based on the total molar amount of the catalyst in the hydroformylation reaction solution.

8. A method according to any of claims 1-3, characterized in that the complexing agent salt is selected from one of the metal salts.

9. The method of claim 8, wherein the complexing agent salt is selected from sodium and/or potassium salts.

10. The method of claim 9, wherein the complexing agent is one or more of citrate, tartrate, hexametaphosphate, pyrophosphate, tripolyphosphate, methylglycine diacetate, glutamate diacetate, hydroxyethylidenediacetate, ethylene glycol bis (β -diaminoethyl) ethyl ether-N, N' -tetraacetate, dihydroxyethyl glycinate, aminodimethylidene phosphonate, aminotrimethylidene phosphonate, ethylenediamine tetramethylene phosphonate, diethylenetriamine pentamethylene phosphonate, hydroxyethylethylenediamine trimethylene phosphonate.

11. The process according to any one of claims 1 to 3, wherein the complexing agent is added in an amount more than one time the molar amount of the hydroformylation catalyst, and/or wherein the extraction treatment is carried out for a time of from 0.1 to 2 hours at a temperature of from 20 to 100 ℃.

12. The process of claim 11, wherein the complexing agent is added in an amount of 1 to 5 times the molar amount of the hydroformylation catalyst, and/or the extraction treatment is carried out for a period of 0.5 to 1 hour at a temperature of 60 to 80 ℃.

13. The process of any one of claims 1 to 3, wherein the pre-carbonylation reaction is carried out at a temperature of 50 to 200 ℃ and a pressure of 2 to 100MPa, the amount of olefin added is 1 to 1000 times the molar amount of the hydroformylation catalyst, the amount of synthesis gas is 1 time or more the molar amount of the olefin, and the reaction time is 0.5 to 10 hours.

14. The method according to any one of claims 1 to 3, wherein the reaction solution after the hydroformylation reaction is produced by the catalytic reaction of olefin and synthesis gas at a temperature of 50 to 200 ℃ and a pressure of 2 to 100 MPa.

15. The process according to any one of claims 1 to 3, characterized in that the olefin is selected from olefins from C2 to C20.

16. A process according to any one of claims 1 to 3 wherein the olefin hydroformylation catalyst is selected from salts of metals which are one or more of Rh, Co, Ir, Ru, Os, Fe, Pd or Pt, optionally the catalyst further comprises a ligand selected from one or more of phosphorus-containing ligands, nitrogen-containing ligands.

17. The process according to claim 16, wherein the metal used is cobalt or rhodium.