Ruthenium hydroxide and its preparation method

Abstract

This application belongs to the field of chemical product preparation technology and discloses a method for preparing ruthenium hydroxide. The method first dissolves ruthenium chloride solid in dilute hydrochloric acid solution and filters out insoluble matter to obtain intermediate liquid one. Then, an alkaline solution is added dropwise to intermediate liquid one while stirring and heating until the pH value of intermediate liquid one reaches between 7 and 8 to obtain intermediate liquid two. Finally, intermediate liquid two is separated into solid and liquid and dried to obtain ruthenium hydroxide. The alkaline solution is selected from at least one of carbamide and ethylenediamine. This application reduces the content of impurity elements in the obtained ruthenium hydroxide and improves the purity of ruthenium hydroxide by optimizing the alkaline solution. In addition, this application also discloses a ruthenium hydroxide.

Description

Technical Field

[0001] This application relates to the field of chemical product preparation technology, and in particular to a ruthenium hydroxide and its preparation method. Background Technology

[0002] Ruthenium metal is a highly selective hydrogenation catalyst, capable of achieving hydrogenation reduction reactions of alkenes, carbonyl compounds, aromatic carbocyclic compounds, and aromatic heterocyclic compounds with high regioselectivity and stereoselectivity, while requiring relatively low activity to induce olefin isomerization or hydrogenolysis reactions. Its compounds are widely used as catalyst precursors in various industries. Using ruthenium hydroxide as an intermediate, ruthenium nitrite and ruthenium acetate can be prepared through simple chemical reactions; both are major compounds in catalytic precursors. In other words, ruthenium hydroxide is a key intermediate for preparing ideal catalyst precursors. Studies have found that ruthenium nitrate without halogen elements is an ideal ruthenium precursor, but currently, industrially produced ruthenium nitrate products generally contain significant amounts of sodium (Na). + Cl - Plasma, and these impurity elements, significantly inhibit the performance and activity of ruthenium-based catalysts. The main reason is that ruthenium hydroxide produced industrially from ruthenium nitrate carries too many impurities, affecting the performance of the final product. Researching methods for preparing high-purity ruthenium hydroxide is of significant research importance and will contribute to improving the application and development of ruthenium-based metal compounds.

[0003] Chinese patent application 201811179402.7 discloses a method for preparing ruthenium acetate. Using ruthenium trichloride as the starting material, ruthenium hydroxide is obtained by adding alkali, then dissolved in nitric acid, precipitated by adding alkali, filtered and washed, and then acetic acid solution is added. The mixture is heated under reflux for 1-4 hours, cooled, and concentrated to obtain a liquid or solid ruthenium acetate product. Further examination of the specification reveals that in the preparation of ruthenium acetate, ruthenium hydroxide is first prepared from ruthenium. Specifically, it is described as follows: "Prepare a deionized aqueous solution of ruthenium(III), add alkali to the above solution, adjust the pH value of the solution to 8-10, stir, filter, and wash to obtain ruthenium hydroxide;"

[0004] Further observation of the instruction manual reveals that the ruthenium(III) in this scheme originates from at least one of ruthenium(III) trichloride, ruthenium(III) trichloride hydrate, ruthenic acid, sodium ruthenate, and potassium ruthenate.

[0005] The alkaline solution is at least one of sodium hydroxide solution, sodium carbonate solution, potassium hydroxide solution, potassium carbonate solution, and potassium bicarbonate solution.

[0006] It is evident that although the above scheme demonstrates that ruthenium hydroxide can be prepared using alkaline solutions, the alkaline solutions disclosed do not include either carbamide or ethylenediamine.

[0007] Chinese patent application 202210753198.5 discloses a method for preparing ruthenium acetate, which involves mixing an aqueous solution of a ruthenium compound with an alkali or an aqueous solution of an alkali to obtain an aqueous ruthenium solution; heating the aqueous ruthenium solution to adjust the pH, reacting for a period of time, aging, and filtering to obtain a ruthenium hydroxide precipitate; dissolving the ruthenium hydroxide precipitate with an aqueous acetic acid solution and hydrochloric acid, repeatedly generating the ruthenium hydroxide precipitate to reduce the halogen content of the precipitate; mixing the ruthenium hydroxide precipitate with an aqueous acetic acid solution containing alcohol and heating under reflux for a period of time, and then repeatedly adding hydrazine hydrate solution under an inert atmosphere and under reflux until the system has no visible insoluble matter and the system turns dark green, thus obtaining ruthenium acetate;

[0008] As can be seen from the above scheme, in the intermediate process of preparing ruthenium acetate, ruthenium hydroxide is first obtained by heating an aqueous ruthenium solution and then adjusting the pH. Further observation of the instruction manual of this scheme shows that the pH adjustment is achieved by an alkali or an aqueous solution of an alkali, wherein the alkali is one or more of MOH, MCO3, MHCO3 and MOAc, M is an alkali metal or ammonium, and the mass fraction of the alkali in the aqueous solution is 1-40%. It can be seen that the alkali solution disclosed in the above scheme does not include either carbamide or ethylenediamine.

[0009] The problem this solution aims to solve is: how to reduce the impurity content in the prepared ruthenium hydroxide by optimizing the alkaline solution during the ruthenium hydroxide preparation process. Summary of the Invention

[0010] The purpose of this application is to reduce the impurity content in the prepared ruthenium hydroxide by optimizing the alkaline solution during the preparation process of ruthenium hydroxide.

[0011] To achieve the above objectives, this application discloses a method for preparing ruthenium hydroxide, comprising the following steps:

[0012] Step 1: Dissolve the ruthenium compound in an acidic solution and filter out the insoluble matter to obtain intermediate solution one;

[0013] Step 2: Add alkaline solution dropwise to intermediate solution one obtained in step 1 at a rate of 8-13 ml / min while stirring and heating until the pH value of intermediate solution one reaches between 7 and 8, to obtain intermediate solution two;

[0014] Step 3: Separate the solid and liquid phases of the intermediate liquid obtained in Step 2 and dry it to obtain ruthenium hydroxide;

[0015] The alkaline solution is selected from at least one of carbamide and ethylenediamine.

[0016] The acidic solution is selected from at least one of hydrochloric acid, bromic acid, and sulfuric acid;

[0017] The ruthenium compound is selected from at least one of ruthenium chloride, ruthenium bromide, and ruthenium sulfate.

[0018] It should be noted that since intermediate solution one is obtained by dissolving ruthenium oxide solid in an acidic solution, the pH value of intermediate solution one is low. Intermediate solution one is acidic or weakly acidic. In step 2, the pH value of intermediate solution one tends to increase with the addition of alkali solution. Therefore, even though the pH value is constantly increasing with the addition of alkali solution in step 2, it can still be set to pH 7. Furthermore, in the experiment, we found that intermediate solution two can be successfully prepared with a pH value of 7.

[0019] Preferably, the alkaline solution is a mixture of carbamide and ethylenediamine, and the mass ratio of carbamide to ethylenediamine is 1:0.5 to 2;

[0020] More preferably, the mass ratio of carbamide to ethylenediamine includes, but is not limited to, 1:0.5, 1:1, 1:1.5, and 1:2.

[0021] Preferably, the mass fraction of carbamide and / or ethylenediamine in the alkaline solution is 15-20%.

[0022] More preferably, the alkaline solution contains both carbamide and ethylenediamine, and the total mass fraction of carbamide and ethylenediamine is 15-20%.

[0023] More preferably, the total mass fraction of carbamide and ethylenediamine includes, but is not limited to, 15%, 16%, 17%, 18%, 19%, and 20%.

[0024] Preferably, the concentration of ruthenium compound in the intermediate liquid is 55–100 g / L;

[0025] More preferably, the concentration of ruthenium compound in intermediate liquid one includes, but is not limited to, 55 g / L, 60 g / L, 65 g / L, 70 g / L, 75 g / L, 80 g / L, 85 g / L, 90 g / L, 95 g / L, and 100 g / L.

[0026] Preferably, step 2 specifically involves: adding alkaline solution dropwise to the intermediate liquid I obtained in step 1 at a rate of 8-13 ml / min until the pH value of the intermediate liquid I reaches between 7 and 8, and then maintaining the temperature for 0.5-1.5 h. While adding the alkaline solution, the intermediate liquid I is stirred and heated, wherein the temperature of the intermediate liquid I is 48-75°C, and the speed of the stirrer is 1200-2040 r / min.

[0027] Preferably, in step 3, a centrifuge is used to perform solid-liquid separation on intermediate liquid II. The centrifuge speed is 4800-5200 r / min, and the centrifugation time is 7-12 min.

[0028] Preferably, step 3 specifically involves: separating the intermediate liquid and solid-liquid mixture obtained in step 2, then placing the solid obtained after the intermediate liquid and solid-liquid separation in an infrared drying oven for 2 to 3.5 hours, and then placing it in a vacuum drying oven at 55 to 85°C to dry it, thereby obtaining ruthenium hydroxide.

[0029] Preferably, in step 1, the acidic solution is hydrochloric acid and the concentration of hydrochloric acid is 0.5 to 1.5 mol / L.

[0030] In addition, this application also discloses a ruthenium hydroxide prepared by the above-described method, wherein the mass fraction of ruthenium in the ruthenium hydroxide is 60-71%.

[0031] Preferably, the ruthenium hydroxide contains less than 8 ppm of sodium, less than 8 ppm of chlorine, less than 10 ppm of iron, less than 10 ppm of silver, and less than 10 ppm of aluminum.

[0032] The beneficial effects of this application are as follows: This application reduces the impurity content in the prepared ruthenium hydroxide by optimizing the alkaline solution during the preparation process. On the one hand, the alkaline solution selected in this application is less likely to introduce metal element impurities compared to traditional alkaline solutions. On the other hand, during the experiment, we were pleasantly surprised to find that when the alkaline solution was compounded, the mass fraction of ruthenium in the finished ruthenium hydroxide product was increased to a certain extent, while the impurity content was further reduced. Detailed Implementation

[0033] The present application will be clearly and completely described below with reference to its embodiments. It should be noted that, unless specific conditions are specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0034] Example 1

[0035] Step 1: Dissolve ruthenium chloride (RuCl3) solid in a 0.5 mol / L dilute hydrochloric acid solution. After the RuCl3 solid dissolves, filter out the insoluble matter to prepare a 100 g / L RuCl3 solution, which will give you intermediate solution one.

[0036] Step 2: Prepare an alkaline solution with a carbonamide mass fraction of 15% using carbonamide and deionized water. Then, add the alkaline solution dropwise to intermediate liquid one obtained in step 1 at a dropping rate of 13 ml / min until the pH value of intermediate liquid one reaches between 7 and 8, and keep it warm for 1.5 h to obtain intermediate liquid two. While adding the alkaline solution, stir and heat intermediate liquid one. During the stirring and heating process, keep the temperature of intermediate liquid one at 48℃ and the speed of the stirrer at 2040 r / min.

[0037] Step 3: Use a centrifuge to separate the intermediate liquid II obtained in step 2 into solid and liquid components. The centrifuge speed is 4800 r / min and the centrifugation time is 12 min. Then, place the solid obtained after solid-liquid separation of intermediate liquid II into an infrared drying oven and dry it for 2 h. Then, place it into a vacuum drying oven at 85℃ and dry it to obtain ruthenium hydroxide.

[0038] Example 2

[0039] Step 1: Dissolve RuCl3 solid in a 1.5 mol / L dilute hydrochloric acid solution. After the RuCl3 solid is dissolved, filter out the insoluble matter to prepare a 55 g / L RuCl3 solution, which will give you intermediate solution one.

[0040] Step 2: Prepare an alkaline solution with a carbonamide mass fraction of 20% using carbonamide and deionized water. Then, add the alkaline solution dropwise to intermediate solution one obtained in step 1 at a dropping rate of 8 ml / min until the pH value of intermediate solution one reaches between 7.8 and 8, and keep it warm for 0.5 h to obtain intermediate solution two. While adding the alkaline solution, stir and heat intermediate solution one, where the temperature of intermediate solution one is 75℃ and the speed of the stirrer is 1200 r / min.

[0041] Step 3: Use a centrifuge to separate the intermediate liquid II obtained in Step 2 into solid and liquid components. The centrifuge speed is 5200 r / min and the centrifugation time is 7 min. Then, place the solid obtained after solid-liquid separation of intermediate liquid II into an infrared drying oven and dry it for 3.5 h. Then, place it into a vacuum drying oven at 55 ℃ and dry it to obtain ruthenium hydroxide.

[0042] Example 3

[0043] Step 1: Dissolve RuCl3 solid in a 1 mol / L dilute hydrochloric acid solution. After the RuCl3 solid is dissolved, filter out the insoluble matter to prepare a 75 g / L RuCl3 solution, which will give you intermediate solution one.

[0044] Step 2: Prepare an alkaline solution with a carbonamide mass fraction of 18% using carbonamide and deionized water. Add the alkaline solution dropwise to intermediate solution one obtained in step 1 at a dropping rate of 10 ml / min until the pH value of intermediate solution one reaches between 7.5 and 8, and keep it warm for 1 hour to obtain intermediate solution two. While adding the alkaline solution, stir and heat intermediate solution one, where the temperature of intermediate solution one is 60℃ and the speed of the stirrer is 1600 r / min.

[0045] Step 3: Use a centrifuge to separate the intermediate liquid II obtained in step 2 into solid and liquid components. The centrifuge speed is 5000 r / min and the centrifugation time is 10 min. Then, place the solid obtained after solid-liquid separation of intermediate liquid II into an infrared drying oven and dry it for 3 h. Then, place it into a vacuum drying oven at 70 ℃ and dry it to obtain ruthenium hydroxide.

[0046] Example 4

[0047] It is basically the same as Example 1, except that the alkaline solution in step 1 is prepared by ethylenediamine and deionized water, and the mass fraction of ethylenediamine is 15%.

[0048] Example 5

[0049] The process is basically the same as in Example 1, except that in step 1, the alkaline solution is prepared from carbamide, ethylenediamine and deionized water, and the sum of the mass fractions of carbamide and ethylenediamine is 15%, wherein the mass ratio of carbamide to ethylenediamine is 1:1.

[0050] Comparative Example 1

[0051] It is basically the same as Example 1, except that in step 1 the alkaline solution is prepared by sodium hydroxide and deionized water, and the mass fraction of sodium hydroxide is 15%.

[0052] Comparative Example 2

[0053] It is basically the same as Example 1, except that the alkaline solution in step 1 is prepared by potassium hydroxide and deionized water, and the mass fraction of potassium hydroxide is 15%.

[0054] Comparative Example 3

[0055] It is basically the same as Example 1, except that the alkaline solution in step 1 is prepared by ammonium acetate and deionized water, and the mass fraction of ammonium acetate is 15%.

[0056] Comparative Example 4

[0057] It is basically the same as Example 1, except that the alkaline solution in step 1 is prepared by ammonium carbonate and deionized water, and the mass fraction of ammonium carbonate is 15%.

[0058] Comparative Example 5

[0059] The process is basically the same as in Example 1, except that step 2 is as follows: an alkaline solution with a carbonamide mass fraction of 15% is prepared using carbonamide and deionized water. Then, the alkaline solution is added dropwise to the intermediate liquid I prepared in step 1 at a dropping rate of 20 ml / min until the pH value of the intermediate liquid I reaches between 7 and 8, and then kept at this temperature for 1.5 h. While adding the alkaline solution, the intermediate liquid I is stirred and heated, with the temperature of the intermediate liquid I being 48°C and the stirring speed being 2040 r / min.

[0060] Comparative Example 6

[0061] The process is basically the same as in Example 1, except that step 2 is as follows: an alkaline solution with a carbonamide mass fraction of 15% is prepared using carbonamide and deionized water. Then, the alkaline solution is added dropwise to the intermediate liquid I prepared in step 1 at a dropping rate of 3 ml / min until the pH value of the intermediate liquid I reaches between 7 and 8, and then kept at this temperature for 1.5 h. While adding the alkaline solution, the intermediate liquid I is stirred and heated, with the temperature of the intermediate liquid I being 48°C and the stirring speed being 2040 r / min.

[0062] Performance testing:

[0063] The contents of ruthenium and impurity elements in the ruthenium hydroxide prepared in the examples and comparative examples were detected by GDMS. The test results are shown in Table 1.

[0064] Table 1

[0065]

[0066]

[0067] Results analysis:

[0068] 1. As can be seen from Examples 1-4, when the concentration of hydrochloric acid, the concentration of ruthenium chloride solution, the concentration and type of solute in the alkaline solution, and the dropping rate are slightly changed, the impurity content of ruthenium hydroxide prepared in Examples 1-4 is not significantly different. Therefore, we believe that when the above parameters are slightly adjusted, the impurity content of ruthenium hydroxide will not fluctuate too much.

[0069] 2. As can be seen from Examples 1 and 5, when the solute in the alkaline solution is compounded, the impurity content of ruthenium hydroxide shows a certain downward trend, while the relative content of ruthenium in ruthenium hydroxide increases. We speculate that the reason for this phenomenon is that the compounding of carbamide, as a weak alkaline substance, and ethylenediamine, as an alkaline substance, reduces the rate of pH change, making the pH change during the reaction process more stable. On the other hand, the addition of ethylenediamine, a relatively strong alkaline substance, makes the reaction complete more quickly, reducing the time for impurity elements to precipitate.

[0070] 3. As can be seen from Example 1 and Comparative Examples 1-4, when sodium hydroxide, potassium hydroxide, ammonium acetate, and ammonium carbonate are used instead of carbamide, the impurity content of Comparative Examples 1-4 all show a significant upward trend. We believe that the reason for this phenomenon is that the use of sodium hydroxide, potassium hydroxide, ammonium acetate, and ammonium carbonate introduces impurity metal elements into intermediate liquid 2, resulting in an increase in the impurity content of the final ruthenium hydroxide.

[0071] 4. As can be seen from Example 1 and Comparative Examples 5-6, when the dropping speed of the alkaline solution is significantly changed, the impurity content of ruthenium hydroxide increases. We believe that the reason for this phenomenon is that if the dropping speed is too fast, the pH value fluctuates too much, resulting in poor stability of the reaction process. Conversely, if the dropping speed is too slow, the reaction rate is too slow, which leads to the precipitation of impurity elements.

[0072] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing ruthenium hydroxide, characterized in that, Includes the following steps: Step 1: Dissolve the ruthenium compound in an acidic solution and filter out the insoluble matter to obtain intermediate solution one; Step 2: Add alkaline solution dropwise to intermediate solution one obtained in step 1 at a dropping rate of 8-13 ml / min while stirring and heating until the pH value of intermediate solution one reaches between 7 and 8, to obtain intermediate solution two; Step 3: Separate the solid and liquid phases of the intermediate liquid obtained in Step 2 and dry them to obtain ruthenium hydroxide; The alkaline solution is a mixture of carbamide, ethylenediamine and deionized water, and the mass ratio of carbamide to ethylenediamine is 1:0.5 to 2. The acidic solution is selected from at least one of hydrochloric acid and sulfuric acid; The ruthenium compound is selected from at least one of ruthenium chloride, ruthenium bromide, and ruthenium sulfate.

2. The method for preparing ruthenium hydroxide according to claim 1, characterized in that, The concentration of ruthenium oxide in the intermediate solution is 55–100 g / L.

3. The method for preparing ruthenium hydroxide according to claim 1, characterized in that, Step 2 specifically involves adding alkaline solution dropwise to the intermediate liquid I obtained in step 1 at a rate of 8–13 ml / min until the pH value of the intermediate liquid I reaches between 7 and 8, and then maintaining the temperature for 0.5–1.5 h. While adding the alkaline solution, the intermediate liquid I is stirred and heated, wherein the temperature of the intermediate liquid I is 48–75°C, and the speed of the stirrer is 1200–2040 r / min.

4. The method for preparing ruthenium hydroxide according to claim 1, characterized in that, In step 3, a centrifuge is used to separate the intermediate liquid into solid and liquid components. The centrifuge speed is 4800-5200 r / min and the centrifugation time is 7-12 min.

5. The method for preparing ruthenium hydroxide according to claim 1, characterized in that, Step 3 specifically involves separating the intermediate liquid and solid obtained in step 2, then placing the solid obtained after the intermediate liquid and solid separation in an infrared drying oven for 2 to 3.5 hours, and then placing it in a vacuum drying oven at 55 to 85°C to dry it, thereby obtaining ruthenium hydroxide.

6. The method for preparing ruthenium hydroxide according to claim 1, characterized in that, In step 1, the acidic solution is hydrochloric acid and the concentration of hydrochloric acid is 0.5 to 1.5 mol / L.

7. The method for preparing ruthenium hydroxide according to claim 1, characterized in that, The mass fraction of ruthenium in the ruthenium hydroxide is 60-71%.

8. The method for preparing ruthenium hydroxide according to claim 1, characterized in that, The ruthenium hydroxide contains less than 8 ppm of sodium, less than 8 ppm of chlorine, less than 10 ppm of iron, less than 10 ppm of silver, and less than 10 ppm of aluminum.

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