Preparation method of dichlorophenyl ruthenium (II) dimer

Abstract

The invention belongs to the technical field of ruthenium catalysts, and particularly relates to a preparation method of a dichlorophenyl ruthenium (II) dimer. The invention provides a preparation method of a dichlorophenyl ruthenium (II) dimer, which comprises the following steps: mixing ruthenium trichloride hydrate, 1, 3-cyclohexadiene, a reducing agent and a solvent, and carrying out redox reaction to obtain the dichlorophenyl ruthenium (II) dimer, the reducing agent is N, N '-dimethylformamide; the temperature of the oxidation-reduction reaction is 15-30 DEG C. According to the preparation method provided by the invention, ruthenium trichloride hydrate and 1, 3-cyclohexadiene are used as raw materials, N, N '-dimethylformamide is used as a reducing agent, the reaction is carried out through a one-pot method, the reaction can be smoothly carried out at room temperature, the steps are simple, the requirement on equipment is relatively low, and batch industrial production is easy to realize.

Description

Technical Field

[0001] The invention belongs to the technical field of ruthenium catalysts, and in particular relates to a method for preparing a dichlorophenylruthenium (II) dimer. Background Art

[0002] Ruthenium catalyst is a highly active catalyst widely used in petrochemical industry, fuel cells, biomedicine and other technical fields. Among them, dichlorophenylruthenium (II) dimer is one of the most widely used homogeneous catalysts and is also the raw material for synthesizing other highly efficient ruthenium catalysts.

[0003] In the related technologies involving the synthesis of dichlorophenylruthenium (II) dimer, hydrated ruthenium trichloride and cyclohexadiene are usually used as reaction raw materials, ethanol is used as reaction solvent, and the reaction is carried out under reflux conditions at 80°C. There are also related technologies that first react the reaction system under microwave irradiation at 130°C for a certain period of time, and then cool the reaction solution to -78°C. However, due to the high operating requirements of the above scheme and the difficulty in meeting the reaction conditions, the preparation of dichlorophenylruthenium (II) dimer is currently basically at the laboratory stage, and only trace products can be obtained, which cannot meet market demand. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing a dichlorophenylruthenium (II) dimer. The reaction conditions of the preparation method provided by the present invention are easy to meet, and large-scale preparation of the dichlorophenylruthenium (II) dimer can be achieved.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a dichlorophenylruthenium (II) dimer, comprising the following steps:

[0007] Hydrated ruthenium trichloride, 1,3-cyclohexadiene, a reducing agent and a solvent are mixed to carry out an oxidation-reduction reaction to obtain the dichlorophenylruthenium (II) dimer; the reducing agent is N,N'-dimethylformamide; and the temperature of the oxidation-reduction reaction is 15-30°C.

[0008] Preferably, the hydrated ruthenium chloride is ruthenium chloride trihydrate.

[0009] Preferably, the molar ratio of the hydrated ruthenium trichloride to 1,3-cyclohexadiene is 1:2.5-4.5.

[0010] Preferably, the molar ratio of the hydrated ruthenium trichloride to N,N'-dimethylformamide is 1:5-10.

[0011] Preferably, the solvent comprises one or more of water, methanol and ethanol.

[0012] Preferably, the mass ratio of the hydrated ruthenium trichloride to the volume ratio of the solvent is 1 g:5-10 mL.

[0013] Preferably, the redox reaction time is 3 to 5 hours.

[0014] Preferably, after the redox reaction, the obtained reaction system is filtered, washed and dried in sequence.

[0015] Preferably, the washing reagent comprises one or more of methanol, ethanol and acetone.

[0016] Preferably, the drying temperature is 45-60° C. and the drying time is 4-6 hours.

[0017] The invention provides a method for preparing a dichlorophenylruthenium (II) dimer, comprising the following steps: mixing hydrated ruthenium trichloride, 1,3-cyclohexadiene, a reducing agent and a solvent, and performing an oxidation-reduction reaction to obtain the dichlorophenylruthenium (II) dimer; the reducing agent is N,N'-dimethylformamide; and the temperature of the oxidation-reduction reaction is 15-30°C. The preparation method provided by the present invention uses hydrated ruthenium trichloride and 1,3-cyclohexadiene as raw materials, and N,N'-dimethylformamide as a reducing agent. The reaction is carried out by a one-pot method, and the reaction can proceed smoothly at room temperature. Since trivalent ruthenium has a certain oxidation ability, cyclohexadiene can be dehydrogenated to benzene and coordinate with metal ruthenium, and in the 1,3-cyclohexadiene molecule, the presence of conjugated double bonds makes the reaction relatively easy; while the two double bonds in 1,4-cyclohexadiene are not conjugated, so the reducibility is relatively low, and it needs to undergo an intermediate transition state to react with hydrated ruthenium trichloride, which increases the difficulty of its reaction with hydrated ruthenium trichloride. N,N'-dimethylformamide as a reducing agent can not only reduce trivalent ruthenium to divalent ruthenium at room temperature, but also has good solubility for the reaction raw material hydrated ruthenium trichloride. At room temperature, 1g of hydrated ruthenium trichloride only needs 1mL to be completely dissolved. Therefore, 1,3-cyclohexadiene is selected as the raw material and N,N'-dimethylformamide is selected as the reducing agent. The reaction can be carried out at room temperature, and the steps are simple, the equipment requirements are low, and it is easy to realize mass industrial production.

[0018] Furthermore, the preparation method provided by the present invention can shorten the reaction time and greatly improve the product yield. It can be seen from the data of the embodiment that the yield of the obtained dichlorophenylruthenium (II) dimer based on ruthenium is more than 99.5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 The hydrogen spectrum of dichlorophenylruthenium (II) dimer prepared in Example 1;

[0021] Figure 2 The carbon spectrum of dichlorophenylruthenium (II) dimer prepared in Example 1;

[0022] Figure 3 This is the infrared spectrum of the dichlorophenylruthenium (II) dimer prepared in Example 1. DETAILED DESCRIPTION

[0023] The present invention provides a method for preparing a dichlorophenylruthenium (II) dimer, comprising the following steps:

[0024] Hydrated ruthenium trichloride, 1,3-cyclohexadiene, a reducing agent and a solvent are mixed to carry out an oxidation-reduction reaction to obtain the dichlorophenylruthenium (II) dimer; the reducing agent is N,N'-dimethylformamide; and the temperature of the oxidation-reduction reaction is 15-30°C.

[0025] In the present invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art, wherein the hydrated ruthenium trichloride, 1,3-cyclohexadiene, and reducing agent are all commercially available analytically pure products.

[0026] In the present invention, the hydrated ruthenium trichloride is preferably ruthenium trichloride trihydrate; the mass percentage of ruthenium in the ruthenium trichloride trihydrate is preferably 37.35-38.65%, and in a specific embodiment, the mass percentage of ruthenium can be 37.35%, 38% or 38.65%. The hydrated ruthenium trichloride used in the present invention has good solubility and is conducive to the reaction.

[0027] In the present invention, the molar ratio of the hydrated ruthenium trichloride to 1,3-cyclohexadiene is preferably 1:2.5-4.5. In a specific embodiment, the molar ratio of the hydrated ruthenium trichloride to 1,3-cyclohexadiene can be 1:2.5, 1:3.5 or 1:4.5.

[0028] In the present invention, the molar ratio of the hydrated ruthenium chloride to N,N'-dimethylformamide is preferably 1:5-10. In a specific embodiment, the molar ratio of the hydrated ruthenium chloride to N,N'-dimethylformamide can be 1:5, 1:8 or 1:10.

[0029] In the present invention, the solvent preferably includes one or more of water, methanol and ethanol. In a specific embodiment, the solvent can be distilled water; the mass ratio of the hydrated ruthenium chloride to the volume ratio of the solvent is preferably 1g:5-10mL. In a specific embodiment, the mass ratio of the hydrated ruthenium chloride to the volume ratio of the solvent can be 1g:5mL, 1g:8mL or 1g:10mL. The preparation method provided by the present invention can use water as the solvent, which greatly reduces the production cost and can achieve green environmental protection.

[0030] In the present invention, the temperature of the redox reaction is 15-30°C. In a specific embodiment, the temperature of the redox reaction can be 15°C, 20°C, 25°C or 30°C. The time is preferably 3-5h. In a specific embodiment, the time of the redox reaction can be 3h, 4h or 5h.

[0031] In the present invention, after the redox reaction, the obtained reaction system is preferably filtered, washed and dried in sequence; the washing reagent preferably includes one or more of methanol, ethanol and acetone, and in a specific embodiment, the washing reagent can be methanol; the washing reagent temperature is preferably 0-2°C, and in a specific embodiment, the washing reagent temperature can be 0°C or 2°C; the drying temperature is preferably 45-60°C, and in a specific embodiment, the drying temperature can be 45°C, 50°C, 55°C or 60°C; the drying time is preferably 4-6h, and in a specific embodiment, the drying time can be 4h, 5h or 6h. The washing of the present invention is to remove the unreacted 1,3-cyclohexadiene.

[0032] The preparation method provided by the present invention uses hydrated ruthenium trichloride and 1,3-cyclohexadiene as raw materials, N,N'-dimethylformamide as a reducing agent, and reacts by a one-pot method. The reaction can proceed smoothly at room temperature. Since trivalent ruthenium has a certain oxidation ability, cyclohexadiene can be dehydrogenated to benzene and metal ruthenium coordination, and in the 1,3-cyclohexadiene molecule, the reaction is relatively easy due to the presence of conjugated double bonds; and the two double bonds in 1,4-cyclohexadiene are not conjugated, so the reducibility is relatively low, and it needs to undergo an intermediate transition state to react with hydrated ruthenium trichloride, which increases the difficulty of its reaction with hydrated ruthenium trichloride. Therefore, the raw material selects 1,3-cyclohexadiene as a raw material, which can react at room temperature, and the steps are simple, the equipment requirements are low, and it is easy to realize batch industrial production.

[0033] Furthermore, the preparation method provided by the present invention can shorten the reaction time and greatly improve the product yield. It can be seen from the data of the embodiment that the yield of the obtained dichlorophenylruthenium (II) dimer based on ruthenium is more than 99.5%.

[0034] In order to further illustrate the present invention, the preparation method of the dichlorophenylruthenium (II) dimer provided by the present invention is described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0035] Example 1

[0036] 500 g of ruthenium trichloride trihydrate (ruthenium content is 38.65%) was dissolved in 2500 mL of distilled water, and then 834 g of N, N'-dimethylformamide and 459 g of 1,3-cyclohexadiene were added. The reaction was stirred at room temperature of 20°C for 3.5 hours, and a large amount of orange solid was precipitated. After filtration, the filter cake was washed twice with 2°C cold methanol and dried at 50°C for 4.5 hours to obtain 477.25 g of orange solid, which is dichlorophenylruthenium (II) dimer, with a yield of 99.8% based on ruthenium.

[0037] Example 2

[0038] 500 g of ruthenium trichloride trihydrate (ruthenium content is 38.65%) was dissolved in 3000 mL of distilled water, and then 834 g of N, N'-dimethylformamide and 459 g of 1,3-cyclohexadiene were added. The reaction was stirred at room temperature of 25°C for 3.5 hours, and a large amount of orange solid was precipitated. After filtration, the filter cake was washed twice with 0°C cold methanol and dried at 45°C for 4.6 hours to obtain 477.25 g of orange solid, which is dichlorophenylruthenium (II) dimer, with a yield of 99.8% based on ruthenium.

[0039] Example 3

[0040] 500 g of ruthenium trichloride trihydrate (ruthenium content is 38.65%) was dissolved in 3500 mL of distilled water, and then 1118 g of N, N'-dimethylformamide and 612 g of 1,3-cyclohexadiene were added. The reaction was stirred at room temperature of 30°C for 4 hours, and a large amount of orange solid was precipitated. After filtration, the filter cake was washed twice with 2°C cold methanol and dried at 50°C for 4 hours to obtain 477.26 g of orange solid, which is dichlorophenylruthenium (II) dimer, with a yield of 99.8% based on ruthenium.

[0041] Example 4

[0042] 1000 g of ruthenium trichloride trihydrate (ruthenium content is 38.65%) was dissolved in 4000 mL of distilled water, and then 1668 g of N, N'-dimethylformamide and 918 g of 1,3-cyclohexadiene were added. The reaction was stirred at room temperature of 30°C for 4.5 hours, and a large amount of orange solid was precipitated. After filtration, the filter cake was washed twice with 0°C cold methanol and dried at 60°C for 6 hours to obtain 954.45 g of orange solid, which is dichlorophenylruthenium (II) dimer, with a yield of 99.8% based on ruthenium.

[0043] Comparative Example 1

[0044] 10 g of ruthenium trichloride trihydrate (ruthenium content is 38.65%) was dissolved in 40 mL of distilled water, and then 16.7 g of N,N'-dimethylformamide and 9.2 g of 1,4-cyclohexadiene were added. The mixture was stirred at room temperature of 30°C for 4.5 h. No solid was precipitated. A large amount of solvent was removed by rotary evaporation. There was a mixture of some orange solid and black solid, indicating that only a small part of the reaction occurred, and most of the hydrated ruthenium trichloride did not react. It is difficult for 1,4-cyclohexadiene to react completely at room temperature.

[0045] Comparative Example 2

[0046] 10 g of ruthenium trichloride trihydrate (ruthenium content is 38.65%) was dissolved in 50 mL of distilled water, and then 16.7 g of hydrazine hydrate and 9.2 g of 1,3-cyclohexadiene were added. The reaction was stirred at room temperature of 20°C for 5 hours. Some black solids were produced. A large amount of solvent was removed by rotary evaporation, and a mixture of some orange solids and black solids was obtained, indicating that only a small part of the reaction was performed to obtain a mixture, and the purity of the target product was low.

[0047] Comparative Example 3

[0048] 1000 g of ruthenium trichloride trihydrate (ruthenium content of 38.65%) was dissolved in 4000 mL of ethanol, heated to 85°C and refluxed with stirring for 6 h, a large amount of red solid precipitated, filtered, the filter cake was washed twice with 0°C cold methanol, and dried at 60°C for 6 h to obtain 760.45 g of red solid, which was dichlorophenylruthenium (II) dimer, with a yield of 79.5% based on ruthenium.

[0049] Test Case

[0050] The dichlorophenylruthenium (II) dimer obtained in Example 1 was subjected to elemental analysis and characterization. The obtained hydrogen spectrum, carbon spectrum and infrared spectrum are shown in Figures 1 to 3 .

[0051] Elemental analysis: Theoretical value (%): C 28.82, H 2.42; Found value (%): C 28.83, H 2.44. The found value is consistent with the theoretical value.

[0052] Depend on Figure 1 It can be seen that the hydrogen spectrum ( 1 H NMR, 500 MHz, DMSO), chemical shift (ppm): 5.95 (s, 6H), 2.48 for the solvent peak, and 3.33 for the water peak in the solvent.

[0053] Depend on Figure 2 It can be seen that the carbon spectrum ( 13 C NMR, 500 MHz, DMSO), chemical shift (ppm): 87.67, 39.54 is the solvent peak of DMSO.

[0054] Depend on Figure 3 Visible, infrared spectrum IR (cm -1 , KBr): 3074, 3036, 1744, 1496, 1433, 1427, 843.

[0055] The detection results of elemental analysis, hydrogen spectrum, carbon spectrum and infrared spectrum show that the product obtained in Example 1 is consistent with the target compound of dichlorophenylruthenium (II) dimer.

[0056] It can be seen from the above examples that the preparation method provided by the present invention is a method for synthesizing dichlorophenylruthenium (II) dimer with simple operation, high conversion rate, low cost and high efficiency, and is suitable for mass industrial production.

[0057] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a dichlorophenylruthenium (II) dimer, characterized in that: The following steps are involved: Hydrated ruthenium trichloride, 1,3-cyclohexadiene, a reducing agent and a solvent are mixed to carry out an oxidation-reduction reaction to obtain the dichlorophenylruthenium (II) dimer; the reducing agent is N,N'-dimethylformamide; and the temperature of the oxidation-reduction reaction is 15-30°C.

2. The preparation method according to claim 1, characterized in that: The hydrated ruthenium chloride is ruthenium chloride trihydrate.

3. The preparation method according to claim 1 or 2, characterized in that: The molar ratio of the hydrated ruthenium trichloride to 1,3-cyclohexadiene is 1:2.5-4.

5.

4. The preparation method according to claim 1 or 2, characterized in that: The molar ratio of the hydrated ruthenium trichloride to N,N'-dimethylformamide is 1:5-10.

5. The preparation method according to claim 1, characterized in that: The solvent includes one or more of water, methanol and ethanol.

6. The preparation method according to claim 1 or 5, characterized in that: The mass ratio of the hydrated ruthenium trichloride to the volume ratio of the solvent is 1 g:5-10 mL.

7. The preparation method according to claim 1, characterized in that: The oxidation-reduction reaction time is 3 to 5 hours.

8. The preparation method according to claim 1, characterized in that: After the oxidation-reduction reaction, the obtained reaction system is filtered, washed and dried in sequence.

9. The preparation method according to claim 8, characterized in that: The washing reagent includes one or more of methanol, ethanol and acetone; the washing is performed 1 to 2 times.

10. The preparation method according to claim 8, characterized in that: The drying temperature is 45-60° C. and the drying time is 4-6 hours.

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