A method for preparing trichlorohexaammine ruthenium

Abstract

The application discloses a preparation method of trichlorohexaammine ruthenium and belongs to the field of metal organic compound synthesis. The method comprises the following steps: (1) mixing a ruthenium precursor with a mixture of hydrazine and hydrazine hydrochloride and heating to obtain a yellow solution; (2) heating the mixture until the mixture becomes a uniform transparent yellow solution and then continuing to boil for a period of time; (3) adding a certain amount of an oxidizing agent into the obtained yellow solution to obtain a reaction stock solution of trichlorohexaammine ruthenium; and (4) separating the product through low-temperature recrystallization and washing with acetone to obtain pure trichlorohexaammine ruthenium. The method is under the premise of one-pot method, the ruthenium precursor used is more extensive, and the by-product ammonia generated in the reaction of hydrazine is fully utilized, so that the number of reagents required to be added is reduced, the use of a catalyst is avoided, and therefore, the method is simpler to operate, lower in cost, more environmentally friendly and convenient for large-scale synthesis and production.

Description

Technical Field

[0001] This invention relates to the field of organometallic compound synthesis, and to a method for synthesizing ruthenium complexes, particularly a method for preparing trichlorohexamineruthenium. Background Technology

[0002] Trichlorohexamineruthenium is a chemical industrial raw material, mainly used as an electron mediator in the field of biological electronic sensors, or as a precursor for other ruthenium-based functional materials.

[0003] Currently, most known literature and foreign patents describe the preparation of trichlorohexamineruthenium via the oxidation of dichlorohexamineruthenium. For example, patent JP2005145750A discloses a method for quantitatively oxidizing dichlorohexamineruthenium using oxygen, which improves the purity of the synthesized product. Because dichlorohexamineruthenium is unstable, in actual production, it is often first synthesized from a ruthenium chloride precursor, and then the freshly prepared dichlorohexamineruthenium is immediately oxidized to synthesize trichlorohexamineruthenium. This two-step reduction-oxidation synthesis method suffers from problems such as cumbersome processes and low overall yield.

[0004] Therefore, newly disclosed patents in recent years have attempted to combine the above two-step synthesis method into a one-pot synthesis of trichlorohexaammineruthenium. For example, the method disclosed in patent CN109574097A uses an alkaline earth metal catalyst to catalyze the reduction of ruthenium chloride salts with concentrated ammonia to obtain dichlorohexaammineruthenium, and then oxidizes it by directly adding an oxidant (such as hydrogen peroxide, chlorine, or one or more) under non-separation conditions to obtain trichlorohexaammineruthenium. The method disclosed in patent CN111041555A uses a mixture of ammonium chloride and ammonia to pretreat ruthenium chloride salts, then adds hydrazine hydrate or hydrazine hydrochloride for azeotropic reduction to obtain dichlorohexaammineruthenium, and finally oxidizes it by directly adding an oxide (such as sodium chlorate, potassium chlorate, sodium hypochlorite, potassium hypochlorite, or one or more) to the reaction solution to obtain trichlorohexaammineruthenium. However, all of the above methods require the use of large amounts of ammonia, ammonium chloride, and alkaline earth metal compound catalysts, and ammonia gas is generated as a byproduct during the reaction. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the above-mentioned shortcomings and provide a new method for preparing trichlorohexamineruthenium.

[0006] The technical solution of this invention is as follows:

[0007] A method for preparing trichlorohexamineruthenium, comprising the following steps:

[0008] (1) Mix a certain amount of hydrazine hydrate, concentrated hydrochloric acid and ruthenium precursor;

[0009] (2) Heat the above mixture until it becomes a uniform, transparent yellow solution, and then continue to boil it for a period of time.

[0010] (3) Add a certain amount of oxidant to the above solution and stir for a period of time under heating conditions until the solution becomes a pale yellow suspension and no longer changes;

[0011] (4) The reaction solution was cooled, recrystallized and filtered to obtain a pale yellow trichlorohexammonium ruthenium solid. Finally, it was washed with an organic solvent to obtain a pure trichlorohexammonium ruthenium product.

[0012] Furthermore:

[0013] In step (1), the ruthenium precursor is one or a combination of ruthenium trichloride, ruthenium tetrachloride, and ruthenium chloride; the ratio of hydrazine hydrate to hydrochloric acid is 10-1:1, preferably 4-2:1; the ratio of hydrazine hydrate to ruthenium precursor is 100-5:1, preferably 30-10:1.

[0014] In step (2), the heating temperature is 60-100 degrees Celsius, preferably 50-90 degrees Celsius; the heating time is 1-4 hours; the oxidant can be hydrogen peroxide, ozone, chlorine, chlorate, or hypochlorite oxidant, and the ratio of the oxidant to the ruthenium precursor is controlled at 10-0.2:1 depending on the different oxide species added; the heating temperature is 40-100 degrees Celsius, preferably 50-90 degrees Celsius; and the heating time is 0.5-6 hours.

[0015] Compared with the prior art, the beneficial effects of the present invention include:

[0016] (1) Ruthenium precursors have a wider range of applications and are not limited to ruthenium chloride.

[0017] (2) Fewer additives are required. The raw materials required are only ruthenium precursor, hydrazine hydrate and hydrochloric acid. Ammonia, ammonium chloride and catalysts are not required. The operation is simpler and the cost is lower.

[0018] (3) Low pollutant emissions. Due to the reduction in the required auxiliary reagents and the utilization of ammonia, a byproduct of hydrazine decomposition during the reaction, pollutant emissions are reduced.

[0019] Therefore, this method has the advantages of simpler operation, lower cost and fewer pollutants, and is more suitable for the large-scale synthesis of trichlorohexamineruthenium. Attached Figure Description

[0020] Figure 1 The infrared spectrum of trichlorohexamineruthenium obtained in Example 1 of this invention. Detailed Implementation

[0021] For ease of understanding, the present invention will be described in detail below through specific embodiments. It should be particularly noted that these descriptions are merely exemplary and do not constitute a limitation on the scope of the invention. Many variations and modifications of the invention will be apparent to those skilled in the art based on the discussion in this specification.

[0022] Example 1

[0023] 20 mL of hydrazine hydrate (85%) was mixed with 10 mL of concentrated hydrochloric acid (35%). After the mixture was allowed to return to room temperature, 4.21 g of solid ruthenium trichloride trihydrate was added to the mixture. The resulting blood-red suspension was heated to 70°C, and after 2 hours, a yellow solution was obtained. Heating was continued for 20 minutes, and then 10 mL of hydrogen peroxide (30%) was added in portions to the reaction solution, and the mixture was stirred at 50°C for 2 hours. The yellow solution gradually turned into a pale yellow suspension, which was then recrystallized at 0°C to obtain pale yellow crystals. 3.94 g of pure ruthenium trichlorohexaminetrimonium was obtained by filtration, washing with acetone, and vacuum drying, with a yield of 79%. Elemental analysis results: Theoretical values: ruthenium 32.64%, hydrogen 5.86%, nitrogen 27.14%; Detected values: ruthenium 32.58%, hydrogen 5.89%, nitrogen 27.23%.

[0024] Infrared detection results:

[0025] Theoretical value of δ(NH) is 1338 cm⁻¹ -1 (s), 1316cm -1 (vs); δ(NH) detection value 1337 cm⁻¹ -1 (s), 1317cm -1 (vs) No other impurities such as NH4Cl (δ(NH)=1401cm) -1 (s)), N2H5Cl (δ(NH)=1496cm -1 The obvious characteristic absorption peak of (s)).

[0026] Example 2

[0027] 20 mL of hydrazine hydrate (85%) was mixed with 10 mL of concentrated hydrochloric acid (35%). After the mixture was allowed to return to room temperature, 6.09 g of sodium ruthenium chloride (ruthenium content 26.7%) was added to the mixture. The resulting blood-red suspension was heated to 70°C, and after 2 hours, a yellow solution was obtained. Heating was continued for 20 minutes, and then 10 mL of hydrogen peroxide (30%) was added in portions to the reaction solution, and the mixture was stirred at 50°C for 2 hours. The yellow solution gradually turned into a pale yellow suspension, which was then recrystallized at 0°C to obtain pale yellow crystals. 3.33 g of pure trichlorohexamineruthenium was obtained by filtration, washing with acetone, and vacuum drying, with a yield of 67%.

[0028] Elemental analysis results:

[0029] Theoretical value: Ruthenium 32.64%; Detected value: Ruthenium 32.61%.

[0030] Example 3

[0031] 20 mL of hydrazine hydrate (85%) was mixed with 5 mL of concentrated hydrochloric acid (35%). After the mixture was allowed to return to room temperature, 3.91 g of solid ruthenium tetrachloride was added to the mixture. The resulting blood-red suspension was heated to 70°C, and after 2 hours, a yellow solution was obtained. Heating was continued for 20 minutes, and then 10 mL of hydrogen peroxide (30%) was added in portions to the reaction solution, and the mixture was stirred at 50°C for 2 hours. The yellow solution gradually transformed into a pale yellow suspension, which was then recrystallized at 0°C to obtain pale yellow crystals. 3.77 g of pure trichlorohexamineruthenium chloride was obtained by filtration, washing with acetone, and vacuum drying, with a yield of 76%.

[0032] Elemental analysis results:

[0033] Theoretical value: Ruthenium 32.64%; Detected value: Ruthenium 32.55%.

[0034] Example 4

[0035] 200 mL of hydrazine hydrate (85%) and 120 mL of concentrated hydrochloric acid (35%) were mixed in an ice-water bath. After the temperature stabilized, 42.12 g of solid ruthenium trichloride was added in portions to the mixture. The resulting blood-red suspension was heated to 70°C, and after 4 hours, a yellow solution was obtained. Heating was continued for 1 hour, then cooled to room temperature, and 100 mL of hydrogen peroxide (30%) was slowly added dropwise to the reaction solution. The solution was slowly heated to 45°C and stirred for 6 hours. The yellow solution gradually transformed into a pale yellow suspension, which was then recrystallized at 0°C to obtain pale yellow crystals. 40.03 g of pure trichlorohexamineruthenium was obtained by filtration, washing with acetone, and vacuum drying, with a yield of 80%.

[0036] Elemental analysis results:

[0037] Theoretical value: Ruthenium 32.64%; Detected value: Ruthenium 32.62%.

[0038] Example 5

[0039] 20 mL of hydrazine hydrate (85%) was mixed with 10 mL of concentrated hydrochloric acid (35%). After the mixture was allowed to return to room temperature, 4.21 g of solid ruthenium trichloride trihydrate was added to the mixture. The resulting blood-red suspension was heated to 70°C, and after 2 hours, a yellow solution was obtained. Heating was continued for 20 minutes, and then 6 mL of sodium hypochlorite (1% (w / w)) was added dropwise to the reaction solution, and the mixture was stirred at 50°C for 2 hours. The yellow solution gradually transformed into a pale yellow suspension, which was then recrystallized at 0°C to obtain pale yellow crystals. 3.74 g of pure ruthenium trichlorohexaminetrimonium was obtained by filtration, washing with acetone, and vacuum drying, with a yield of 75%. Elemental analysis results: Theoretical value: ruthenium 32.64%; Detected value: ruthenium 32.39%.

[0040] Example 6

[0041] 20 mL of hydrazine hydrate (85%) was mixed with 10 mL of concentrated hydrochloric acid (35%). After the mixture was allowed to return to room temperature, 2.15 g of solid ruthenium trichloride trihydrate and 3.02 g of sodium ruthenate were added to the mixture. The resulting blood-red suspension was heated to 70°C, and after 2 hours, a yellow solution was obtained. Heating was continued for 20 minutes, and then 10 mL of hydrogen peroxide (30%) was added in portions to the reaction solution, and the mixture was stirred at 50°C for 2 hours. The yellow solution gradually turned into a pale yellow suspension, which was then recrystallized at 0°C to obtain pale yellow crystals. 3.97 g of pure ruthenium trichlorohexaminetrimonium was obtained by filtration, washing with acetone, and vacuum drying, with a yield of 79%. Elemental analysis results: Theoretical value: ruthenium 32.64%; Detected value: ruthenium 32.46%.

[0042] As can be seen from Examples 1-5, this method mainly uses hydrazine hydrate, hydrochloric acid, and a ruthenium precursor for mixing. Without adding other auxiliary reagents or catalysts, the mixed solution is heated to reduce the ruthenium precursor. The ammonia obtained from the decomposition of hydrazine hydrate and hydrazine hydrochloride under heating conditions is then combined with ruthenium to obtain dichlorohexaammineruthenium. Trichlorohexaammineruthenium is then obtained through a one-pot synthesis method by directly adding an oxidant to the reaction solution. Compared with the methods described in CN109574097A and CN111041555A, the starting material is no longer limited to ruthenium chloride, and the applicable ruthenium precursors are expanded to include ruthenium chlorides such as ruthenium trichloride and ruthenium tetrachloride.

[0043] Furthermore, this method eliminates the need for concentrated ammonia, ammonium chloride, and alkaline earth metal compound catalysts, effectively utilizing the ammonia gas generated as a byproduct during the reaction while greatly simplifying the operation process. Therefore, this invention represents a significant advancement over methods disclosed in the prior art.

Claims

1. A method for preparing trichlorohexamineruthenium, characterized in that, Includes the following steps: Step (1): Mix a certain amount of hydrazine hydrate, concentrated hydrochloric acid and ruthenium precursor; the ruthenium precursor is one or a combination of ruthenium trichloride, ruthenium tetrachloride and ruthenium chloride; the molar ratio of hydrazine hydrate to hydrochloric acid is 10-1:1; the molar ratio of hydrazine hydrate to ruthenium precursor is 100-5:1; Step (2): Heat the mixture obtained in step (1) to 60-100 ℃ until the mixture becomes a uniform and transparent yellow solution, and then continue to boil for a period of time. Step (3): Add a certain amount of oxidant to the reaction system obtained in step (2), and stir for a period of time under heating conditions until the solution becomes a pale yellow suspension and no longer changes, to obtain the reaction stock solution of trichlorohexamineruthenium; Step (4): The reaction solution obtained in step (3) is cooled, recrystallized, and filtered to obtain a pale yellow trichlorohexammonium ruthenium solid. Finally, it is washed with an organic solvent to obtain a pure trichlorohexammonium ruthenium product.

2. The method for preparing trichlorohexamineruthenium according to claim 1, characterized in that, The heating time in step (2) is 1-4 hours.

3. The method for preparing trichlorohexamineruthenium according to claim 1, characterized in that, Continue boiling for 0-2 hours in step (2).

4. The method for preparing trichlorohexamineruthenium according to claim 1, characterized in that, The oxidant mentioned in step (3) includes hydrogen peroxide, ozone, chlorine, chlorate, and hypochlorite oxidants.

5. The method for preparing trichlorohexamineruthenium according to claim 1, characterized in that, In step (3), the ratio of the amount of oxidant added to the mass of ruthenium precursor is controlled at 10-0.2:

1.

6. The method for preparing trichlorohexamineruthenium according to claim 1, characterized in that, In step (3), the heating temperature is 40-100 ℃ and the heating time is 0.5-6 hours.

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