A preparation method of dichlorophenylruthenium (II) dimer

Abstract

The present invention belongs to the technical field of ruthenium catalysts, and in particular to a method for preparing a dichlorophenylruthenium (II) dimer. The present 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, performing an oxidation-reduction reaction to obtain the dichlorophenylruthenium (II) dimer; the reducing agent is N,N'-dimethylformamide; the temperature of the oxidation-reduction reaction is 15 to 30 ° C. 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 process. The reaction can be smoothly carried out at room temperature, the steps are simple, the equipment requirements are relatively low, and batch industrial production is easily achieved.

Description

Technical Field

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

[0002] Ruthenium catalysts are highly active and widely used in the 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 a raw material for the synthesis of other highly efficient ruthenium catalysts.

[0003] In the related technologies involving the synthesis of dichlorophenylruthenium (II) dimers, hydrated ruthenium trichloride and cyclohexadiene are usually used as reaction raw materials, ethanol is used as the 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 liquid to -78°C. However, due to the high operational requirements and difficult reaction conditions of the above schemes, the preparation of dichlorophenylruthenium (II) dimers currently remains at the laboratory stage, and only trace amounts of 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 and subjected to 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 trichloride is ruthenium trichloride 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 includes 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 preparation method of 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 in a one-pot process, and the reaction can proceed smoothly at room temperature. Since trivalent ruthenium has a certain oxidizing ability, it can dehydrogenate cyclohexadiene to benzene and coordinate with metallic ruthenium. In addition, the presence of conjugated double bonds in the 1,3-cyclohexadiene molecule makes the reaction relatively easy. However, the two double bonds in 1,4-cyclohexadiene are not conjugated, so the reducibility is relatively low. Its reaction with hydrated ruthenium trichloride requires an intermediate transition state, 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 achieve mass industrial production.

[0018] Furthermore, the preparation method provided by the present invention can shorten the reaction time and greatly improve the product yield. As can be seen from the data in the examples, the yield of the obtained dichlorophenylruthenium (II) dimer based on ruthenium is above 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 following briefly introduces the drawings required for use in the embodiments. 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 any creative work.

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

[0021] Figure 2 This is 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 and subjected to 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% to 38.65%. 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, which 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 trichloride to N,N'-dimethylformamide is preferably 1:5-10. In a specific embodiment, the molar ratio of the hydrated ruthenium trichloride 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 production costs and can achieve 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 4-6 hours, and in a specific embodiment, the drying time can be 4 hours, 5 hours, or 6 hours. The washing process of the present invention is to remove 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 oxidizing ability, cyclohexadiene can be dehydrogenated to benzene and coordinated with metallic 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. It needs to go through 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, can react at room temperature, and the steps are simple, the equipment requirements are low, and it is easy to achieve batch industrial production.

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

[0034] To further illustrate the present invention, the preparation method of the dichlorophenylruthenium (II) dimer provided by the present invention is described in detail below with reference to 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: 38.65%) was dissolved in 2500 mL of distilled water, and 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, during which a large amount of orange solid precipitated. The solid was filtered, and 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 an orange solid, which was dichlorophenylruthenium (II) dimer. The yield based on ruthenium was 99.8%.

[0037] Example 2

[0038] 500 g of ruthenium trichloride trihydrate (ruthenium content: 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, during which a large amount of orange solid precipitated. The solid was filtered, and the filter cake was washed twice with cold methanol at 0°C and dried at 45°C for 4.6 hours to obtain 477.25 g of an orange solid, which was dichlorophenylruthenium (II) dimer. The yield based on ruthenium was 99.8%.

[0039] Example 3

[0040] 500 g of ruthenium trichloride trihydrate (ruthenium content: 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 precipitated. The solid was filtered, and 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 an orange solid, which was dichlorophenylruthenium (II) dimer. The yield based on ruthenium was 99.8%.

[0041] Example 4

[0042] 1000 g of ruthenium trichloride trihydrate (ruthenium content: 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 precipitated. The solid was filtered, and the filter cake was washed twice with cold methanol at 0°C and dried at 60°C for 6 hours to obtain 954.45 g of an orange solid, which was dichlorophenylruthenium (II) dimer. The yield based on ruthenium was 99.8%.

[0043] Comparative Example 1

[0044] 10 g of ruthenium trichloride trihydrate (ruthenium content of 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 and reacted at room temperature of 30°C for 4.5 hours. No solid was precipitated. A large amount of solvent was removed by rotary evaporation, and a mixture of some orange solid and black solid was obtained, 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 carried out, resulting in a mixture and low purity of the target product.

[0047] Comparative Example 3

[0048] 1000 g of ruthenium trichloride trihydrate (ruthenium content: 38.65%) was dissolved in 4000 mL of ethanol and heated at 85°C with reflux stirring for 6 h. A large amount of red solid precipitated. The mixture was filtered, and 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 a red solid, which was dichlorophenylruthenium (II) dimer. The yield based on ruthenium was 79.5%.

[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 FIG. 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 results of elemental analysis, hydrogen spectrum, carbon spectrum and infrared spectrum showed that the product obtained in Example 1 was consistent with the target compound of dichlorophenylruthenium (II) dimer.

[0056] The above examples show 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 provides a detailed description of the present invention, 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 scope of protection 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; the temperature of the oxidation-reduction reaction is 15-30°C; and the solvent is water.

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

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

7. The preparation method according to claim 1, characterized in that After the redox reaction, the obtained reaction system is filtered, washed and dried in sequence.

8. The preparation method according to claim 7, characterized in that The washing reagent is one or more of methanol, ethanol and acetone; the washing frequency is 1 to 2 times.

9. The preparation method according to claim 7, characterized in that The drying temperature is 45-60° C. and the drying time is 4-6 hours.

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