An in situ synthesis method of tris(beta-diketone) iridium

Abstract

The application belongs to the technical field of noble metal compound preparation, and particularly relates to an in-situ synthesis method of tris(beta-dicarbonyl ketone) iridium, which comprises the following steps: 1) adding iridium powder, hydrochloric acid and strong oxidizing acid into a sealed reaction kettle to perform reaction; 2) filtering the reaction liquid, and sequentially adding water, pH regulator A and ethylene glycol ether solvent into the filtrate to perform reflux reaction; 3) adding beta-dicarbonyl ketone under light-proof condition, and continuing to perform reflux reaction; 4) adding a reducing agent and pH regulator B, and continuing to perform reflux reaction; and 5) cooling, filtering, washing and obtaining the product. The tris(beta-dicarbonyl ketone) iridium obtained by the synthesis method has the characteristics of low chlorine content, low metal impurity content and high stability, and meets the use requirements of precursors such as catalysts, photoelectric materials and MOCVD. Meanwhile, the preparation process has the characteristics of simple operation, good product consistency, high yield and high purity, and is suitable for batch production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of noble metal compound preparation, and particularly relates to an in-situ synthesis method of tris(beta-dicarbonyl ketone) iridium. BACKGROUND

[0002] Among the platinum group metals, iridium has the characteristics of high density (22.65 g / cm3), high melting point (2443℃), high boiling point (4130℃), etc., and has the advantages of high temperature stability, high chemical inertness, resistance to corrosion of various inorganic acids, melts and high temperature silicates, and the characteristics of preventing oxygen element diffusion. These characteristics make the iridium coating have more superior performance than the existing alloy, oxide and other noble metal coatings, and can work for a long time under high temperature oxidation atmosphere and high speed airflow scouring, and is used as a surface layer of high temperature, corrosion resistant and oxidation resistant structural device coating in high temperature turbine engine of spacecraft.

[0003] Meanwhile, iridium has a d orbital with a large splitting energy, and has a strong spin-orbit coupling after coordination with a ligand, which can enhance phosphorescence emission, and has a short triplet state lifetime and high phosphorescence emission efficiency, and is widely used in phosphorescent light emitting materials. In addition, iridium (III) has d2sp3 orbital hybridization, can accept lone pair electrons to form strong metal-metal bonds and metal-ligand bonds, and is widely used in catalysis fields such as isomerization, hydroformylation or carbonylation reactions.

[0004] Tris(beta-dicarbonyl ketone) iridium is the most commonly used one of the relatively simple and stable structures, generally has the properties of extraction, luminescence, laser, volatilization, etc. It is used as a precursor of nano coating, thin film, particulate material, phosphorescent material, catalyst and functional aid. In the beta-dicarbonyl ketone structure, the oxygen of the carbonyl group is bidentate coordinated with iridium to form a stable six-membered ring, which is very stable at room temperature and can be sublimed stably. The MOCVD technology is used to prepare high temperature superconducting film layer with the precursor, and commercialization has been realized.

[0005] Tris(β-dicarbonyl ketone)iridium, a representative product, is generally synthesized via a route that involves the reaction of iridium trichloride with β-dicarbonyl ketone (Hacac) under alkaline conditions. Benett et al. prepared Ir(acac)3 by heating under reflux for 40 hours using hydrated IrCl3, Haacac, and Na2CO3 as raw materials, with a yield of approximately 5-15%. FPDwyer and JE Collins successfully obtained iridium acetylacetone powder from hydrated iridium trichloride via chemical precipitation, achieving a maximum yield of 45%. Patent EP1088812A2 reports the reduction of H2IrCl6 to H3IrCl6 using (NH3)2Cl2. Then, Hacac is added, and the pH is adjusted to 6.5-7.5. After reflux for 48 hours, Ir(acac) is obtained in a yield of 22%. In China, Yan Gexin et al. dissolved iridium trichloride trihydrate in distilled water by heating, stirred under a hydrogen atmosphere, added Hacac and saturated sodium bicarbonate solution and refluxed to obtain iridium acetylacetonate in a yield of 25%. Other methods include Yan Xin et al. reacting iridium chloroacetic acid with sodium hydroxide and ammonia to obtain the product in a yield of 12%. Patent CN106631743A reports a method for solid-phase synthesis of iridium acetylacetonate. Patent CN100425615A reports the yield of tri(hexafluoroacetylacetonate)iridium product by reacting iridium trichloride with hexafluoroacetylacetonate under argon protection.

[0006] Based on the above literature, the tri(β-dicarbonyl ketone)iridium route, represented by iridium acetylacetone, generally involves the reaction of iridium trichloride with acetylacetone under weakly alkaline conditions, with product yields typically ranging from 12% to 45%. Summary of the Invention

[0007] The purpose of this invention is to provide an in-situ synthesis method for tri(β-dicarbonyl ketone)iridium. Using iridium powder as a raw material, this method employs inorganic acid oxidation and coordination to provide a simple, continuous process that combines multiple synthesis steps in a one-pot series, eliminating the need for inert gas protection and achieving a high-purity, high-yield in-situ synthesis of tri(β-dicarbonyl ketone)iridium. The solvents and reagents used in the preparation process are all conventional acids, bases, and alcohol ethers, eliminating the steps of synthesizing, separating, and purifying iridium trichloride. This allows for the direct, high-yield, in-situ synthesis of tri(β-dicarbonyl ketone)iridium while reducing the content of chloride ions, thus improving product quality. The preparation process is characterized by simple operation, good product consistency, high yield, high purity, environmental friendliness, short production cycle, and high finished product rate, making it suitable for mass production.

[0008] Specifically, the present invention provides the following technical solutions:

[0009] An in-situ synthesis method for tris(β-dicarbonyl ketone)iridium, which can be partially referenced Figure 1 This includes the following steps:

[0010] 1) Add iridium powder, hydrochloric acid and a strong oxidizing acid to a sealed reaction vessel and react for a period of time to obtain an iridium reaction solution;

[0011] 2) Filter the iridium reaction solution, add a certain amount of water to the filtrate to dilute the iridium concentration to 120-150 g / L, then add pH adjuster A to adjust the pH value to 5-7, then add a certain amount of ethylene glycol ether solvent to dilute the iridium concentration to 15-30 g / L, raise the temperature to 65-80℃, and reflux for a period of time.

[0012] 3) Add β-dicarbonyl ketone to the reaction solution obtained in step 2) under light-protected conditions, heat to 85-110℃, and reflux for a period of time;

[0013] 4) Add reducing agent and pH adjuster B to the reaction solution obtained in step 3) and adjust the pH value to 8-10. Continue to reflux the reaction at 85-110℃ for a period of time.

[0014] 5) Cool the reaction solution obtained in step 4), filter it to obtain a solid filter cake, and then wash the solid filter cake to obtain the product.

[0015] Preferably, in step 1), the iridium powder has a particle size of 200-300 mesh. The iridium source used in this invention is industrially common 200-300 mesh iridium powder, eliminating the need for the preparation and purification steps of iridium trichloride.

[0016] Preferably, in step 1), the mass of the hydrochloric acid is 5 to 10 times the mass of the iridium powder.

[0017] Preferably, in step 1), the strong oxidizing acid is selected from at least one of concentrated sulfuric acid, concentrated nitric acid, and perchloric acid.

[0018] Preferably, in step 1), the mass of the strong oxidizing acid is 0.2 to 0.5 times the mass of the iridium powder.

[0019] Preferably, in step 1), the reaction temperature is 105–180°C, the time is 3–8 h, and the pressure is 0.3–1 MPa.

[0020] Preferably, in step 2), the pH adjuster A is sodium hydroxide and / or potassium hydroxide. Sodium hydroxide and / or potassium hydroxide can quickly adjust the pH to the desired value while ensuring that the viscosity of the solution is appropriate.

[0021] Preferably, in step 2), the ethylene glycol ether solvent is selected from at least one of ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, and ethylene glycol diethyl ether.

[0022] Preferably, in step 2), the reflux reaction time is 0.5 to 2 hours.

[0023] Preferably, in step 3), the amount of the β-dicarbonyl ketone added is 4 to 10 times the amount of the iridium powder.

[0024] Preferably, in step 3), the reflux reaction time is 6 to 18 hours.

[0025] Preferably, in step 4), the reducing agent is selected from at least one of nitric acid hydrochloride, formic acid, and sodium formate, and is used to reduce tetravalent iridium to trivalent iridium, which facilitates improving product yield.

[0026] Preferably, in step 4), the amount of the reducing agent added is 0.8 to 1.5 times the amount of the iridium powder.

[0027] Preferably, in step 4), the pH adjuster B is selected from at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate. This facilitates the formation of a buffer solution system, ensuring a relatively stable pH, improving iridium conversion rate, and enhancing the washing and filtration efficiency of the precipitate, thus easily removing metallic impurities. While the precipitate obtained using this type of weakly basic pH adjuster is easy to wash, its drawback is that the precipitate is viscous, difficult to filter, and the resulting solution has a high impurity content. Therefore, washing with dilute nitric acid is generally required at the end.

[0028] Preferably, in step 4), the reflux reaction time is 4 to 10 hours.

[0029] Preferably, in step 5), an ice-water bath is used for cooling.

[0030] Preferably, in step 5), the washing process specifically involves: first washing the solid filter cake with water 3 to 7 times to remove residual metal impurities and chlorine from the precipitate, obtaining an iridium precipitate with impurities removed, and then washing it 3 to 5 times with nitric acid at a concentration of 0.1 to 2 wt%.

[0031] The beneficial effects of this invention are at least as follows:

[0032] 1) The present invention provides an in-situ synthesis method for tri(β-dicarbonyl ketone)iridium, which uses iridium powder as raw material to obtain tri(β-dicarbonyl ketone)iridium in situ, eliminating a series of processes such as preparation, separation and purification of iridium trichloride or chloroiridium acid, shortening the synthesis route and simplifying the synthesis process;

[0033] 2) The in-situ synthesis method of tri(β-dicarbonyl ketone)iridium provided by the present invention has a precipitation and washing process that can remove iridium tetroxide as a raw material and metal impurities and oxides that may be introduced during the reaction. On the other hand, it is simple to operate and easy to control the consistency of the product. The combined use of pH adjuster A and pH adjuster B can ensure that iridium can react under stable pH conditions to obtain a uniform precipitation, while being easy to wash and filter, with high product yield and production efficiency.

[0034] 3) The in-situ synthesis method of tri(β-dicarbonyl ketone)iridium provided by the present invention has the characteristics of low chlorine content, low metal impurity content and high stability, which meets the requirements of various precursors such as catalysts and MOCVD, and is suitable as a catalyst and MOCVD precursor.

[0035] 4) The in-situ synthesis method of tris(β-dicarbonyl ketone)iridium provided by the present invention has the characteristics of simple operation, good product consistency and high yield, and is suitable for mass production;

[0036] 5) The in-situ synthesis method of tris(β-dicarbonyl ketone)iridium provided by the present invention, wherein the pH adjuster A is preferably sodium hydroxide and / or potassium hydroxide, which can quickly adjust the pH to the required value while ensuring that the viscosity of the solution is appropriate;

[0037] 6) The in-situ synthesis method of tris(β-dicarbonyl ketone)iridium provided by the present invention, wherein the pH adjuster B is preferably at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate, which facilitates the formation of a buffer solution system, ensures that the pH remains relatively stable, improves the iridium conversion rate, and improves the washing and filtration efficiency of the precipitate, making it easier to wash away metal impurities. Attached Figure Description

[0038] Figure 1 This is a synthetic route diagram for the synthesis of tris(β-dicarbonyl ketone)iridium according to the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in the art, or in accordance with the product manual.

[0040] Example 1

[0041] (1) Add 50g of iridium powder to a sealed reaction vessel, add 250mL of hydrochloric acid (concentration 37mol / L) and 25mL of concentrated sulfuric acid (concentration 98%), and stir at 140℃ for 6 hours to obtain an iridium reaction solution (which may contain a small amount of insoluble matter).

[0042] (2) Filter the iridium reaction solution and collect the filtrate in the reaction vessel to obtain an iridium solution. Add about 250 mL of water to the iridium solution to control the iridium concentration to ~125 g / L. Add sodium hydroxide to adjust the pH to 5. Add 1.5 L of ethylene glycol monoethyl ether to dilute the solution and heat under reflux at 80 °C for 2 h.

[0043] (3) After the reaction in (2) is completed, add 65g of 2,4-pentanedione and reflux at 105℃ for 15h to obtain an orange-yellow precipitate.

[0044] (4) Add 25g sodium formate and an appropriate amount of sodium carbonate, adjust the pH value to 10, and continue the reflux reaction at 105℃ for 8 hours. The amount of orange-yellow precipitate increased significantly.

[0045] (5) Cool the solution described in (4) to room temperature in an ice-water bath, filter by pressure, and wash the precipitate repeatedly with water and filter 5 times to remove residual metal impurities and chlorine, thus obtaining an iridium precipitate with impurities removed. Finally, wash the precipitate with impurities removed 5 times with a certain amount of 0.5wt% dilute concentrated nitric acid to obtain 54.80g of tris(2,4-pentanedione)iridium product. 1H NMR (CDCl3, 400MHz): 5.46 (1H), 1.98 (6H); FAB-MS (Fast Atom Bombardment Ionization High Resolution Mass Spectrometry): Measured value m / z = 490.67, theoretical value m / z = 490.54, which is 193 Ir(C5H7O2)3H + Molecular ion peak; Elemental analysis: Measured values ​​C 36.74%, H 4.28%, theoretical values ​​C 36.76%, H 4.29%; ICP-OES analysis showed iridium content of 39.22%, and the content of metallic impurities such as Na, Mg, Al, Fe, Ni, Pd, Ag and chloride ions <50ppm. The calculated reaction yield was 43%.

[0046] Example 2

[0047] (1) Add 200g of iridium powder to a sealed reaction vessel, add 1.5L of concentrated hydrochloric acid and 80mL of perchloric acid (70% concentration), and seal and stir the reaction at 160℃ for 4h to obtain iridium reaction solution.

[0048] (2) Filter the iridium reaction solution and collect the filtrate in the reaction vessel to obtain an iridium solution. Add 300 mL of water to the iridium solution, adjust the pH to 5 with potassium hydroxide, add about 10 L of ethylene glycol dimethyl ether to dilute, and heat to 65 °C and reflux for 2 h.

[0049] (3) Under light-protected conditions, after the reaction in (2) is completed, add 1020.0g of hexafluoroacetylacetone, increase the reflux temperature to 110℃, reflux for 8h, and obtain an orange-yellow precipitate.

[0050] (4) Add 60g of hydrazine hydrochloride and an appropriate amount of potassium carbonate, adjust the pH value to 10, and continue to reflux for 10h under the temperature conditions described in (3) to obtain a large amount of orange-yellow precipitate.

[0051] (5) The solution described in (4) was cooled to room temperature in an ice-water bath. After pressure filtration, the precipitate was repeatedly washed with water and filtered 7 times to remove residual metal impurities and chlorine, thus obtaining an iridium precipitate with impurities removed. Finally, the precipitate with impurities removed was washed 3 times with a certain amount of 0.5wt% dilute concentrated nitric acid to obtain 442.6g of product. FAB-MS: Measured value m / z = 490.74, theoretical value m / z = 490.54, which is... 193 Ir(C5H7O2)3H + Molecular ion peak; Elemental analysis: Measured values ​​C 36.65%, H 4.21%, theoretical values ​​C 36.76%, H 4.29%; ICP-OES analysis showed iridium content of 23.50%, and the content of metallic impurities such as Na, Mg, Al, Fe, Ni, Pd, Ag and chloride ions <50ppm. The calculated reaction yield was 52%.

[0052] Example 3

[0053] (1) Add 280g of iridium powder to a sealed reaction vessel, add 2L of concentrated hydrochloric acid and 90mL of concentrated nitric acid (65%), and stir the reaction at 120℃ for 7h to obtain iridium reaction solution.

[0054] (2) The iridium reaction liquid was filtered, and the filtrate was collected in the reaction vessel to obtain an iridium solution. Sodium hydroxide was added to adjust the pH value to 5, and then 15L of ethylene glycol diethyl ether was added. The mixture was heated to reflux at 70°C for 0.5h.

[0055] (3) Under light-protected conditions, after the reaction in (2) is completed, add 2126g of raw material 1-phenyl-1,3-butanedione and continue the reflux reaction. Increase the temperature to 100℃ and the time is 18h to obtain an orange-yellow precipitate.

[0056] (4) Add a certain amount of 78g formic acid and an appropriate amount of sodium carbonate, adjust the pH value to 8, and continue to reflux for 10h under the temperature conditions described in (3) to obtain a large amount of orange-yellow precipitate.

[0057] (5) Cool the solution described in (4) in an ice-water bath, filter by pressure, and repeatedly wash the precipitate with water five times and then wash it three times with 0.2wt% nitric acid to obtain 573.9g of product. FAB-MS: Measured value m / z = 490.58, theoretical value m / z = 490.54, which is... 193 Ir(C5H7O2)3H + Molecular ion peak; Elemental analysis: Measured values ​​C 36.59%, H 4.31%, theoretical values ​​C 36.76%, H 4.29%; ICP-OES analysis showed iridium content of 28.30%, and the content of metallic impurities such as Na, Mg, Al, Fe, Ni, Pd, Ag and chloride ions <50ppm. The calculated reaction yield was 58%.

[0058] Example 4

[0059] (1) Add 168g of iridium powder to a sealed reaction vessel, add 1.2L of concentrated hydrochloric acid and 80mL of concentrated sulfuric acid, and stir the reaction at 175℃ for 7h to obtain iridium reaction solution.

[0060] (2) The iridium reaction mixture was hydraulically filtered, and the filtrate was collected in a reaction vessel to obtain an iridium solution. Potassium hydroxide was added to adjust the pH to 7, and 8 L of ethylene glycol dimethyl ether (EDG) was added to dilute the solution. The solution was then heated to reflux. The reflux temperature was 65 °C and the time was 1.5 h.

[0061] (3) After the reaction in (2) is complete, add 3-phenyl-2,4-pentanedione and continue the reflux reaction. The reflux temperature is increased to 90℃ and the time is 14h, resulting in an orange-yellow precipitate.

[0062] (4) Add a certain amount of sodium formate and potassium carbonate, adjust the pH value to 9, and continue to reflux for 8 hours under the temperature conditions described in (3) to obtain a large amount of orange-yellow precipitate.

[0063] (5) Cool the solution described in (4) to room temperature in an ice-water bath, filter by pressure, and repeatedly wash the precipitate with water four times and with 2wt% nitric acid five times to obtain 246.2g of product. FAB-MS: Measured value m / z = 490.78, theoretical value m / z = 490.54, which is... 193 Ir(C5H7O2)3H + Molecular ion peak; Elemental analysis: Measured values ​​C 36.84%, H 4.33%, theoretical values ​​C 36.76%, H 4.29%; ICP-OES analysis showed iridium content of 26.61%, and the content of metallic impurities such as Na, Mg, Al, Fe, Ni, Pd, Ag and chloride ions <50ppm. The calculated reaction yield was 39%.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for in situ synthesis of tris(β-diketonato)iridium, characterized by, The method comprises the following steps: 1) adding iridium powder, hydrochloric acid and strong oxidizing acid into a sealed reaction kettle, and reacting for a period of time to obtain an iridium reaction solution; 2) filtering the iridium reaction solution, adding a certain amount of water into the filtrate to dilute the iridium concentration to 120-150 g / L, then adding pH regulator A to adjust the pH value to 5-7, further adding a certain amount of ethylene glycol ether solvent to dilute the iridium concentration to 15-30 g / L, and heating to 65-80 ℃ to perform reflux reaction for a period of time; 3) adding β-dicarbonyl ketone into the reaction solution obtained in step 2) under light-proof condition, heating to 85-110 ℃ to perform reflux reaction for a period of time; 4) adding a reducing agent and pH regulator B into the reaction solution obtained in step 3), adjusting the pH value to 8-10, and continuing to perform reflux reaction at 85-110 ℃ for a period of time; 5) cooling the reaction solution obtained in step 4), filtering to obtain a solid filter cake, and washing the solid filter cake to obtain the product. In step 1), the reaction temperature is 105-180 ℃, the reaction time is 3-8 h, and the pressure is 0.3-1 MPa. In step 2), the reflux reaction time is 0.5-2 h. In step 3), the reflux reaction time is 6-18 h. In step 4), the reflux reaction time is 4-10 h.

2. The method of in situ synthesis of tris(p-diketonate) iridium according to claim 1, wherein In step 1), the particle size of the iridium powder is 200-300 mesh.

3. The method of in situ synthesis of tris(p-diketonate) iridium according to claim 1 or 2, characterized in that, In step 1), the mass of the hydrochloric acid is 5-10 times the mass of the iridium powder. In step 1), the strong oxidizing acid is at least one selected from concentrated sulfuric acid, concentrated nitric acid and perchloric acid. In step 1), the mass of the strong oxidizing acid is 0.2-0.5 times the mass of the iridium powder.

4. The method of in situ synthesis of tris(p-diketonate) iridium according to claim 1 or 2, characterized in that, In step 2), the pH regulator A is sodium hydroxide and / or potassium hydroxide.

5. The method of in situ synthesis of tris(p-diketonate) iridium according to claim 1 or 2, wherein In step 2), the ethylene glycol ether solvent is at least one selected from ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether and ethylene glycol diethyl ether.

6. The method of in situ synthesis of tris(p-diketonate) iridium according to claim 1 or 2, wherein, In step 3), the amount of substance of the β-dicarbonyl ketone is 4-10 times the amount of substance of the iridium.

7. The method of in situ synthesis of tris(p-diketonate) iridium according to claim 1 or 2, wherein In step 4), the reducing agent is at least one selected from hydrocyanic acid, formic acid and sodium formate.

8. The method of in situ synthesis of tris(p-diketonate) iridium according to claim 1 or 2, wherein, In step 4), the pH regulator B is at least one selected from sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate.

9. The method of in situ synthesis of tris(p-diketonate) iridium according to claim 1 or 2, wherein, In step 5), the washing is specifically as follows: the solid filter cake is first washed with water for 3-7 times to obtain an iridium precipitate from which impurities are removed, and then washed with 0.1-2 wt% nitric acid for 3-5 times.

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