Preparation method of anhydrous acetic acid rare earth raw material and application of anhydrous acetic acid rare earth raw material in synthesis of rare earth nano luminescent material
By heating, stirring and evaporating the rare earth oxide and acetic acid solution in an oil bath pot, anhydrous rare earth acetic acid raw materials were prepared, which solved the problems caused by uneven particle size of existing rare earth acetic acid products and crystallization water, and achieved rare earth nanoluminescence The efficient and environmentally friendly synthesis of materials improves product quality and production efficiency.
Patent Information
- Application Number
- CN202411233316.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-04
- Publication Date
- 2024-12-10
AI Technical Summary
Existing rare earth acetic acid products have problems such as uneven particle size, crystallization water, harsh process conditions, high costs and introduction of impurities, resulting in inconsistent product quality, low yield and environmental pollution, which hinders them in rare earth nanoluminescent materials. Application extension.
采用将稀土氧化物与醋酸溶液在油浴锅中加热搅拌，蒸发至醋酸稀土析出并结晶，随后烘干制备无水醋酸稀土原料，用于稀土纳米发光材料的合成。
It realizes high-purity preparation of anhydrous rare earth acetic acid, simplifies the process flow, reduces production costs, obtains regular uniform nanoparticles and excellent luminescence performance, and solves the problems of inconsistent product quality and environmental pollution.
Smart Images
Figure FT_1 
Figure FT_2 
Figure FT_3
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of rare earth materials, in particular to a method for preparing anhydrous acetic acid rare earth raw material and application of the raw material in the synthesis of rare earth nano luminescent materials. Background Art
[0002] Rare earth acetate has become a hot material in research and industry due to its important applications in many fields such as catalysis, optics, agriculture, corrosion protection and environmental protection. Rare earth acetate has good solubility, easy to control reaction conditions, and can provide a stable and high-purity source of rare earth ions. In many liquid phase synthesis methods of rare earth nanoluminescent materials (such as hydrothermal method, solvothermal method, coprecipitation method and solid-liquid thermal decomposition method, etc.), compared with rare earth chloride, rare earth acetate is easier to decompose into rare earth ions and organic acid coordination, and can participate in the crystal nucleation and growth process in the liquid phase reaction process at a more gentle and controllable rate. The additionally introduced acetate can be decomposed into gas overflow without introducing any impurity elements, so it can achieve controllable preparation of rare earth nanoluminescent materials with high yield, high dispersibility and excellent optical properties.
[0003] For example, Chinese patent CN105694889A discloses an upconversion luminescent material, its preparation method and application, and the rare earth source of the invention includes rare earth acetate. Chinese patent CN117660007A discloses a NaYF4:Yb,Tm@Cs4PbBr6 core-shell structure nanocrystal and its synthesis method, which can obtain high-efficiency upconversion luminescence and can also make the upconversion light continuously adjustable in the visible light range. In the synthesis, the rare earth ions also come from yttrium acetate, ytterbium acetate and thulium acetate.
[0004] However, the existing rare earth acetate products are of varying quality. In the preparation of rare earth nanoluminescent materials, inferior products as rare earth ion raw materials often lead to uneven nanoparticle size and precipitation. In addition, the traditional two-step method for preparing rare earth acetate with crystallization water not only faces challenges such as harsh process conditions, difficult treatment of crystallization mother liquor, high cost and introduction of additional impurity elements, but also easily absorbs moisture and deteriorates during subsequent storage. These problems will lead to inconsistency in product quality, low yield, instability of impurity content, environmental pollution and waste of resources, which seriously hinder the sustainable development and application expansion of rare earth acetate. The academic paper "Experimental Study on the Preparation of Hydrated Rare Earth Acetate with Rare Earth Oxides" studied the preparation of a series of hydrated rare earth acetate by dissolving rare earth oxides with acetic acid and evaporating and crystallizing. However, rare earth acetate with crystallization water will bring an additional cumbersome and time-consuming water removal process in the large-scale batch preparation of rare earth nanoluminescent materials, increasing production costs. In view of the shortcomings of the existing technology and the embarrassment of its application environment, it is urgent to develop a method for preparing anhydrous rare earth acetate that is both simple and environmentally friendly. The rare earth acetate prepared by this new method has no crystal water and is used as a rare earth ion source in the preparation of rare earth nano-luminescent materials, thereby achieving high-yield and high-quality preparation of rare earth nano-luminescent materials. Summary of the invention
[0005] The object of the present invention is to provide a method for preparing anhydrous rare earth acetate raw material. The method provided by the present invention is simple to operate and has low production cost. The prepared rare earth acetate is phase-pure and can be used as a rare earth acetate raw material in the controllable synthesis of various rare earth nano-luminescent materials. The prepared nanoparticles have a regular and uniform morphology and excellent luminescent properties.
[0006] In order to achieve the above object, the present invention adopts the following technical solutions.
[0007] The present invention provides a method for preparing anhydrous acetic acid rare earth raw material, comprising the following steps:
[0008] (1) mixing a rare earth oxide and an acetic acid solution of a certain concentration in a beaker to obtain a mixed liquid;
[0009] (2) placing the beaker of step (1) in an oil bath, heating, stirring and keeping warm for a period of time;
[0010] (3) After the solution is completely clarified, evaporate for a period of time until rare earth acetate begins to precipitate and crystallize at 100°C;
[0011] (4) Drying the crystals obtained in step (3) at a certain temperature for a period of time to obtain anhydrous rare earth acetate RE(CH3CO2)3.
[0012] Wherein, RE is a rare earth element, selected from one of yttrium (Y), scandium (Sc), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) or lutetium (Lu). Constant temperature magnetic stirrer, evaporating dish and high temperature magnetic stirrer are supporting instruments and equipment in the preparation process.
[0013] Preferably, the concentration of the acetic acid solution in step (1) is 25% to 75%; the volume ratio of the mass of the rare earth oxide to the acetic acid solution is (1-10) g: (40-400) mL.
[0014] Preferably, the heating rate in step (2) is 3-7°C / min.
[0015] Preferably, the insulation temperature in step (2) is 100-150° C.; the insulation time is 0.1-10 h;
[0016] Preferably, the stirring rate in step (2) is 100 to 300 r / min.
[0017] Preferably, the evaporation time in step (3) is 0.5 to 4 hours.
[0018] Preferably, in the step (4), the drying temperature is 100 to 160° C. and the drying time is 1 to 5 hours.
[0019] Preferably, the high temperature magnetic stirrer does not lose its magnetic force at 150°C.
[0020] The rare earth acetate RE(CH3CO2)3 prepared as described above has no crystal water.
[0021] The above-mentioned rare earth acetate RE(CH3CO2)3 is used in the preparation of various rare earth nano-luminescent materials based on AREF4 (A is one of Na, K, and Li).
[0022] The present invention provides a preparation method of a full range of anhydrous rare earth acetate raw materials. A rare earth oxide is mixed with an acetic acid solution of a certain concentration in a beaker to obtain a mixed liquid, a constant temperature magnetic stirrer, an evaporating dish and a high temperature magnetic stirrer are configured, and then the beaker is placed in an oil bath pot for heating, stirring and heat preservation for a period of time. After the solution is completely clarified, the evaporating dish is removed, and the evaporation is carried out for a period of time until the rare earth acetate begins to precipitate, and crystallizes at 100°C. The obtained crystals are dried at a certain temperature for a period of time to obtain anhydrous rare earth acetate raw material RE(CH3CO2)3. The preparation method provided by the present invention is simple to operate and has low production cost. The prepared rare earth acetate is phase-pure and is used as a rare earth raw material in the controllable synthesis of various rare earth nano luminescent materials based on AREF4 (A is one of Na, K and Li). The prepared nanoparticles have a regular and uniform morphology and excellent luminescent properties. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 This is a diagram of the preparation process of anhydrous acetic acid rare earth raw materials and their application in the synthesis of rare earth nanoluminescent materials.
[0024] Figure 2 Figure a and Figure b are respectively the X-ray diffraction diagram and the thermogravimetric curve diagram of anhydrous yttrium acetate prepared at different reaction temperatures in Example 1 of the present invention.
[0025] Figure 3 Figure a and Figure b are respectively the X-ray diffraction diagram and the thermogravimetric curve diagram of anhydrous ytterbium acetate prepared at different reaction temperatures in Example 2 of the present invention.
[0026] Figure 4 Figure a and Figure b are respectively the X-ray diffraction diagram and the thermogravimetric curve diagram of anhydrous erbium acetate prepared at different reaction temperatures in Example 3 of the present invention.
[0027] Figure 5 The X-ray diffraction patterns of anhydrous gadolinium acetate, anhydrous holmium acetate, anhydrous lanthanum acetate and anhydrous europium acetate prepared at a certain reaction temperature in Examples 4, 5, 6 and 7 of the present invention.
[0028] Figure 6 Figures a to d are respectively the X-ray diffraction pattern, transmission electron microscope pattern, particle size distribution pattern and photoluminescence pattern of the NaYF4:Yb / Er (18 / 2 mol%) upconversion nanoparticles prepared in Application Example 1 of the present invention.
[0029] Figure 7 Figures a to d in the middle are respectively the X-ray diffraction pattern, transmission electron microscope pattern, particle size distribution pattern and photoluminescence pattern of the LiYbF4:Tm (1 mol%) upconversion nanoparticles prepared in Application Example 2 of the present invention.
[0030] Figure 8Figures a to d in the middle are respectively the X-ray diffraction pattern, transmission electron microscopy pattern, particle size distribution pattern and photoluminescence pattern of the NaErF4@NaYF4 upconversion core-shell nanoparticles prepared in Application Example 3 of the present invention.
[0031] Fig. 9 This is a comparison chart of the X-ray diffraction of anhydrous yttrium acetate prepared in Example 1 of the present invention and rare earth acetate prepared under the experimental conditions reported in the reference paper "Experimental Study on the Preparation of Hydrated Rare Earth Acetate Using Rare Earth Oxides".
[0032] Fig.10 This is a comparison chart of the X-ray diffraction of anhydrous ytterbium acetate prepared in Example 2 of the present invention and rare earth acetate prepared under the experimental conditions reported in the reference paper "Experimental Study on the Preparation of Hydrated Rare Earth Acetate Using Rare Earth Oxides".
[0033] Fig.11 This is a comparison chart of the X-ray diffraction of anhydrous erbium acetate prepared in Example 3 of the present invention and rare earth acetate prepared under the experimental conditions reported in the reference paper "Experimental Study on the Preparation of Hydrated Rare Earth Acetate Using Rare Earth Oxides". DETAILED DESCRIPTION
[0034] The present invention provides a method for preparing anhydrous rare earth acetate, comprising the following steps:
[0035] (1) mixing a rare earth oxide and an acetic acid solution of a certain concentration in a beaker to obtain a mixed liquid;
[0036] (2) placing the beaker of step (1) in an oil bath, heating, stirring and keeping warm for a period of time;
[0037] (3) After the solution is completely clarified, evaporate for a period of time until rare earth acetate begins to precipitate and crystallize at 100°C;
[0038] (4) Drying the crystals obtained in step (3) at a certain temperature for a period of time to obtain rare earth acetate RE(CH3CO2)3.
[0039] Wherein, RE is a rare earth element, selected from one of yttrium (Y), scandium (Sc), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) or lutetium (Lu). Constant temperature magnetic stirrer, evaporating dish and high temperature magnetic stirrer are supporting instruments and equipment.
[0040] The invention mixes a rare earth oxide with an acetic acid solution of a certain concentration in a beaker to obtain a mixed liquid.
[0041] In the present invention, the concentration of the acetic acid solution is 25% to 75%, more preferably 50%; in the present invention, the mass ratio of the rare earth oxide to the volume ratio of the acetic acid solution is (1 to 10) g: (40 to 400) mL, more preferably (4 to 6) g: (160 to 240) mL. The present invention controls the mass ratio of the rare earth oxide to the volume ratio of the acetic acid solution within the above range to promote the complete reaction of each component and obtain rare earth acetate with better performance.
[0042] In the present invention, after the mixing process is completed, the beaker is placed in an oil bath for heating, stirring and keeping warm for a period of time.
[0043] In the present invention, the heating temperature rise rate is 3-7°C / min, more preferably 5°C / min. In the present invention, the stirring rate is 100-300r / min, more preferably 200r / min. In the present invention, the insulation temperature is 100-150°C, more preferably 130°C; in the present invention, the insulation time is 0.1-10h, more preferably 5h. The heating rate, stirring rate, insulation temperature and insulation time of the present invention are within the above ranges to obtain rare earth acetate with better performance.
[0044] In the present invention, after the reaction treatment is completed, the following steps are further included: after the solution is completely clarified, evaporating for a period of time until rare earth acetate begins to precipitate, and crystallizing at 100°C.
[0045] In the present invention, the evaporation time is 0.5 to 4 hours, more preferably 3 hours.
[0046] In the present invention, after the evaporation crystallization treatment is completed, the process further includes: drying the crystals at a certain temperature for a period of time to obtain anhydrous rare earth acetate RE(CH3CO2)3.
[0047] In the present invention, the drying temperature is 100-200° C., more preferably 150° C.; in the present invention, the drying time is 1-5 hours, more preferably 3 hours.
[0048] In the present invention, the rare earth acetate RE(CH3CO2)3 prepared as described above has no crystal water.
[0049] The invention discloses an application of anhydrous rare earth acetate RE(CH3CO2)3 prepared by the method provided by the invention in preparing various rare earth nano luminescent materials based on AREF4 (A is one of Na, K and Li).
[0050] The following will be combined with the specific embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a small part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work, any modifications, equivalent replacements, improvements, etc., should be included in the protection scope of the present invention. The present invention is further described in detail in combination with the drawings and specific embodiments.
[0051] Example 1
[0052] Preparation method of yttrium acetate:
[0053] Mix 5 g of yttrium oxide with 200 mL of 50% acetic acid solution in a 500 mL beaker to obtain a mixed liquid; place the beaker obtained in step (1) on a high-temperature magnetic stirrer, then place the beaker in an oil bath, cover it with an evaporating dish, heat at a heating rate of 5°C / min, stir at a speed of 200 r / min, and keep warm in a 130°C oil bath for 2 hours; after the solution is completely clarified, remove the evaporating dish, evaporate for 2 hours until rare earth acetate begins to precipitate, and then crystallize at 100°C; dry the crystals obtained in step (3) at 150°C for 3 hours to obtain anhydrous yttrium acetate Y(CH3CO2)3.
[0054] Example 2
[0055] Preparation method of ytterbium acetate:
[0056] Mix 5 g of ytterbium oxide with 200 mL of 50% acetic acid solution in a 500 mL beaker to obtain a mixed liquid; place the beaker obtained in step (1) on a high-temperature magnetic stirrer, then place the beaker in an oil bath, cover it with an evaporating dish, heat at a heating rate of 5°C / min, stir at a speed of 200 r / min, and keep warm in a 130°C oil bath for 2.5 hours; after the solution is completely clarified, remove the evaporating dish, evaporate for 2 hours until rare earth acetate begins to precipitate, and then crystallize at 100°C; dry the crystals obtained in step (3) at 150°C for 3 hours to obtain anhydrous ytterbium acetate Yb(CH3CO2)3.
[0057] Example 3
[0058] Preparation method of erbium acetate:
[0059] Mix 5 g of erbium oxide with 200 mL of 50% acetic acid solution in a 500 mL beaker to obtain a mixed liquid; place the beaker obtained in step (1) on a high-temperature magnetic stirrer, then place the beaker in an oil bath, cover it with an evaporating dish, heat at a heating rate of 5°C / min, stir at a speed of 200 r / min, and keep warm in a 120°C oil bath for 6 hours; after the solution is completely clarified, remove the evaporating dish, evaporate for 2 hours until rare earth acetate begins to precipitate, and then crystallize at 100°C; dry the crystals obtained in step (3) at 150°C for 3 hours to obtain anhydrous erbium acetate Er(CH3CO2)3.
[0060] Example 4
[0061] Mix 2 g of gadolinium oxide with 100 mL of 50% acetic acid solution in a 300 mL beaker to obtain a mixed liquid; place the beaker obtained in step (1) on a high-temperature magnetic stirrer, then place the beaker in an oil bath, cover it with an evaporating dish, heat at a heating rate of 5°C / min, stir at a speed of 300 r / min, and keep warm in an oil bath at 110°C for 1.2 h; after the solution is completely clarified, remove the evaporating dish, evaporate for 1 h until rare earth acetate begins to precipitate, and then crystallize at 100°C; dry the crystals obtained in step (3) at 150°C for 2 h to obtain anhydrous gadolinium acetate Gd(CH3CO2)3.
[0062] Example 5
[0063] Mix 2 g of holmium oxide with 100 mL of 50% acetic acid solution in a 300 mL beaker to obtain a mixed liquid; place the beaker obtained in step (1) on a high-temperature magnetic stirrer, then place the beaker in an oil bath, cover it with an evaporating dish, heat at a heating rate of 5°C / min, stir at a speed of 300 r / min, and keep warm in a 120°C oil bath for 3.5 hours; after the solution is completely clarified, remove the evaporating dish, evaporate for 1 hour until rare earth acetate begins to precipitate, and then crystallize at 100°C; dry the crystals obtained in step (3) at 150°C for 2 hours to obtain anhydrous holmium acetate Ho(CH3CO2)3.
[0064] Example 6
[0065] Mix 2 g of lanthanum oxide with 100 mL of 50% acetic acid solution in a 300 mL beaker to obtain a mixed liquid; place the beaker obtained in step (1) on a high-temperature magnetic stirrer, then place the beaker in an oil bath, cover it with an evaporating dish, heat at a heating rate of 5°C / min, stir at a speed of 300 r / min, and keep warm in a 120°C oil bath for 0.3 h; after the solution is completely clarified, remove the evaporating dish, evaporate for 1 h until rare earth acetate begins to precipitate, and then crystallize at 100°C; dry the crystals obtained in step (3) at 150°C for 2 h to obtain anhydrous lanthanum acetate La(CH3CO2)3.
[0066] Example 7
[0067] Mix 2 g of europium oxide with 100 mL of 50% acetic acid solution in a 300 mL beaker to obtain a mixed liquid; place the beaker obtained in step (1) on a high-temperature magnetic stirrer, then place the beaker in an oil bath, cover it with an evaporating dish, heat at a heating rate of 5°C / min, stir at a speed of 300 r / min, and keep warm in a 120°C oil bath for 0.5 h; after the solution is completely clarified, remove the evaporating dish, evaporate for 1 h until rare earth acetate begins to precipitate, and then crystallize at 100°C; dry the crystals obtained in step (3) at 150°C for 2 h to obtain europium acetate Eu(CH3CO2)3.
[0068] Application Example 1
[0069] Yttrium acetate was prepared according to the method of Example 1, ytterbium acetate was prepared according to the method of Example 2, and erbium acetate was prepared according to the method of Example 3. The prepared rare earth acetate was used as the raw material for preparing up-conversion nanoparticles by coprecipitation. The corresponding mass of rare earth acetate powder was weighed according to the input amount of 1 mmol, added to deionized water for ultrasonic dissolution, and then added to a double-necked flask, wherein Y(CH3CO2)3:Yb(CH3CO2)3:Er(CH3CO2)3=80:18:2 (molar ratio). 10 ml of OA and 15 ml of ODE were added to the double-necked flask, stirred at 150°C for 50 min at a speed of 200 r / min to form a yellow transparent solution, and then cooled to 50°C to obtain a precursor solution. According to the input amount of 4mmol and 2mmol, the corresponding mass of NH4F and NaOH powders were weighed respectively, added to the methanol solution for ultrasonic dissolution, and then the methanol solution of NH4F and the solution of NaOH were mixed and ultrasonicated for 10s, and then the mixed methanol solution was quickly added to the above precursor solution and stirred evenly at 300r / min for 40min. Then the temperature was raised to 100℃, and vacuumed for 5min, and then argon was introduced for 1min, followed by vacuuming for 5min, and then argon was introduced for 1min, and this operation was repeated 3 times. During the argon oscillation operation, the mixed solution needs to be stirred continuously, and the stirring speed is 280r / min. Then the temperature was raised to 280℃ for reaction for 90min, and the heating rate was 10℃ / min. The stirring speed was 330r / min during the heating and heat preservation process. Then cool to room temperature, add anhydrous ethanol in a volume ratio of 1:1, mix well and put into a centrifuge at a centrifugal speed of 7000r / min and a centrifugal time of 5min. Add cyclohexane solution to the solid powder obtained by centrifugation and disperse the nanoparticles by ultrasound. Then, make the solution volume 10ml to obtain a solution containing NaYF4:Yb / Er (18 / 2mol%) upconversion nanoparticles.
[0070] Application Example 2
[0071] Ytterbium acetate was prepared according to the method of Example 2, and the prepared rare earth acetate was used as a raw material for preparing upconversion nanoparticles by coprecipitation. According to the input amount of 1 mmol, the corresponding mass of rare earth acetate powder was weighed and added to deionized water for ultrasonic dissolution and then added to a double-necked flask, wherein Yb(CH3CO2)3:Tm(CH3CO2)3=99:1 (molar ratio). 10 ml of OA and 15 ml of ODE were added to a double-necked flask, stirred at 150°C for 50 min at a speed of 200 r / min to form a yellow transparent solution, and then cooled to 50°C to obtain a precursor solution. According to the input amount of 4 mmol and 2 mmol, the corresponding mass of NH4F and LiOH powders were weighed respectively, added to a methanol solution for ultrasonic dissolution, and then the methanol solution of NH4F and the solution of NaOH were mixed for ultrasonic 10 s, and then the mixed methanol solution was quickly added to the above-mentioned precursor solution and stirred evenly at 300 r / min for 40 min. Then the temperature was raised to 100°C, and vacuum was applied for 5 minutes, and then argon was introduced for 1 minute, followed by vacuum application for 5 minutes, and then argon was introduced for 1 minute, and the operation was repeated 3 times. During the argon oscillation operation, the mixed solution needs to be continuously stirred, and the stirring speed is 280r / min. The temperature was raised to 280°C for 90 minutes, and the heating rate was 10°C / min. The stirring speed during the heating and insulation process was 330r / min. Then it was cooled to room temperature, anhydrous ethanol was added in a volume ratio of 1:1, and after mixing evenly, it was placed in a centrifuge at a centrifugal speed of 7000r / min and a centrifugal time of 5 minutes. Cyclohexane solution was added to the solid powder centrifuged and the nanoparticles were dispersed by ultrasound, and then the solution was fixed to 10ml to obtain a solution containing LiYbF4:Tm (1mol%) upconversion nanoparticles.
[0072] Application Example 3
[0073] Yttrium acetate was prepared according to the method of Example 1, and erbium acetate was prepared according to the method of Example 3. The prepared rare earth acetate was used as the raw material for preparing up-conversion core-shell nanoparticles by coprecipitation. According to the input amount of 1mmol, the corresponding mass of erbium acetate powder was weighed, added to deionized water for ultrasonic dissolution, and then added to a double-necked flask. 10ml OA and 15ml ODE were added to a double-necked flask, stirred at 150°C for 50min at a speed of 200r / min to form a yellow transparent solution, and then cooled to 50°C to obtain a precursor solution. According to the input amount of 4mmol and 2mmol, the corresponding mass of NH4F and NaOH powders were weighed respectively, added to the methanol solution for ultrasonic dissolution, and then the methanol solution of NH4F and the solution of NaOH were mixed for ultrasonic 10s, and then the mixed methanol solution was quickly added to the above-mentioned precursor solution and stirred evenly at 300r / min for 40min. Then the temperature was raised to 100 ° C, and vacuum was applied for 5 minutes, and then argon was introduced for 1 minute, followed by vacuum for 5 minutes, and then argon was introduced for 1 minute, and the operation was repeated 3 times. During the argon oscillation operation, the mixed solution needs to be continuously stirred, and the stirring speed is 280r / min. Then the temperature was raised to 280 ° C for 90 minutes, and the heating rate was 10 ° C / min. The stirring speed during the heating and insulation process was 330r / min. Then it was cooled to room temperature, anhydrous ethanol was added in a volume ratio of 1:1, and after mixing evenly, it was placed in a centrifuge at a centrifugal speed of 7000r / min and a centrifugal time of 5 minutes. Cyclohexane solution was added to the solid powder from the centrifuge and the nanoparticles were dispersed by ultrasound, and then the solution was fixed to 10ml to obtain a solution containing NaErF4 upconversion core nanoparticles.
[0074] Then weigh 1mmol of the corresponding mass of yttrium acetate powder, add it to deionized water for ultrasonic dissolution, and then add it to a double-necked flask. Add 10ml OA and 15ml ODE to the double-necked flask, stir at 150℃ for 50min at a speed of 200r / min to form a yellow transparent solution, and then cool to room temperature to obtain a precursor solution. Then add the above 10mL core solution to the shell precursor solution, continue to react at 90℃ for 30min to remove cyclohexane in the solution, and then cool to 50℃. According to the input amount of 4mmol and 2mmol, weigh the corresponding mass of NH4F and NaOH powder respectively, add them to the methanol solution for ultrasonic dissolution, then mix the NH4F methanol solution and the NaOH solution for ultrasonic 10s, and then quickly add the mixed methanol solution to the above precursor solution and stir evenly at 300r / min for 40min. Then heat to 100℃, vacuum for 5min, then pass argon for 1min, then vacuum for 5min, and then pass argon for 1min, and repeat this operation 3 times. During the argon oscillation operation, the mixed solution needs to be stirred continuously, and the stirring speed is 280r / min. Then the temperature is raised to 280℃ for 90min, and the heating rate is 10℃ / min. The stirring speed is 330r / min during the heating and heat preservation process. Then it is cooled to room temperature, anhydrous ethanol is added in a volume ratio of 1:1, and after mixing evenly, it is placed in a centrifuge at a centrifugal speed of 7000r / min and a centrifugal time of 5min. Cyclohexane solution is added to the solid powder from the centrifuge and the nanoparticles are dispersed by ultrasound, and then the solution is fixed to 10ml to obtain a solution containing NaErF4@NaYF4 upconversion core-shell nanoparticles.
[0075] Comparative Example 1
[0076] According to the experimental conditions reported in the reference paper "Experimental Study on the Preparation of Hydrated Rare Earth Acetate with Rare Earth Oxides", the mass volume ratio of yttrium oxide to acetic acid is 1 / 1.8. Take an appropriate amount of glacial acetic acid and dissolve it in pure water to prepare a glacial acetic acid solution with a concentration of 2.5 mol / L. Heat to 75°C at a heating rate of 10°C / min and keep warm. Add 50g of yttrium oxide to the acetic acid solution under stirring to dissolve, evaporate and concentrate the rare earth acetate solution, filter after precipitating rare earth acetate crystals, and air-dry the obtained crystal particles at room temperature. The obtained sample particles are compared with the yttrium acetate obtained in this patent in terms of X-ray diffraction patterns. The X-ray diffraction pattern of the prepared sample particles is quite different from that of the yttrium acetate standard.
[0077] Comparative Example 2
[0078] According to the experimental conditions reported in the reference paper "Experimental Study on the Preparation of Hydrated Rare Earth Acetate with Rare Earth Oxides", the mass volume ratio of ytterbium oxide to acetic acid is 1 / 2.04. Take an appropriate amount of glacial acetic acid and dissolve it in pure water to prepare a glacial acetic acid solution with a concentration of 3 mol / L. Heat to 75°C at a heating rate of 10°C / min and keep warm. Add 50g of yttrium oxide to the acetic acid solution under stirring to dissolve, evaporate and concentrate the rare earth acetate solution, filter after precipitating rare earth acetate crystals, and air-dry the obtained crystal particles at room temperature. The obtained sample particles are compared with the ytterbium acetate obtained in this patent in terms of X-ray diffraction patterns. The X-ray diffraction pattern of the prepared sample particles is quite different from that of the ytterbium acetate standard.
[0079] Comparative Example 3
[0080] According to the experimental conditions reported in the reference paper "Experimental Study on the Preparation of Hydrated Rare Earth Acetate with Rare Earth Oxides", the mass volume ratio of erbium oxide to acetic acid is 1 / 1.8. Take an appropriate amount of glacial acetic acid and dissolve it in pure water to prepare a glacial acetic acid solution with a concentration of 2.5 mol / L. Heat to 75°C at a heating rate of 10°C / min and keep warm. Add 50g of yttrium oxide to the acetic acid solution under stirring to dissolve, evaporate and concentrate the rare earth acetate solution, filter after precipitating rare earth acetate crystals, and air-dry the obtained crystal particles at room temperature. The obtained sample particles are compared with the erbium acetate obtained in this patent in terms of X-ray diffraction patterns. The X-ray diffraction pattern of the prepared sample particles is quite different from that of the erbium acetate standard.
Claims
1. A method for preparing anhydrous acetic acid rare earth raw material RE (CH3CO2) 3, comprising the following steps: (1) mixing a rare earth oxide and an acetic acid solution of a certain concentration in a beaker to obtain a mixed liquid; (2) placing the beaker in step (1) in an oil bath, heating, stirring and keeping warm for a period of time; (3) After the solution is completely clarified, evaporate for a period of time until rare earth acetate begins to precipitate and crystallize at 100°C; (4) Drying the crystals obtained in step (3) at a certain temperature for a period of time to obtain rare earth acetate RE(CH3CO2)3. Wherein, RE is a rare earth element, selected from one of yttrium (Y), scandium (Sc), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) or lutetium (Lu). Constant temperature magnetic stirrer, evaporating dish and high temperature magnetic stirrer are supporting instruments and equipment in the preparation process.
2. The preparation method according to claim 1, characterized in that: The concentration of the acetic acid solution in step (1) is 25% to 75%; the volume ratio of the mass of the rare earth oxide to the acetic acid solution is (1-10) g: (40-400) mL.
3. The preparation method according to claim 1, characterized in that: The heating rate in step (2) is 3-7°C / min.
4. The preparation method according to claim 1, characterized in that: The insulation temperature in step (2) is 100-150° C.; the insulation time is 0.1-10 h.
5. The preparation method according to claim 1, characterized in that: The stirring rate in step (2) is 100 to 300 r / min.
6. The preparation method according to claim 1, characterized in that: The evaporation time in step (3) is 0.5 to 4 hours.
7. The preparation method according to claim 1, characterized in that: The drying temperature in the step (4) is 100 to 200° C. and the drying time is 1 to 5 hours.
8. The preparation method according to claim 1, characterized in that: The rare earth acetate RE(CH3CO2)3 prepared in step (4) contains no crystal water.
9. Use of the anhydrous rare earth acetate RE(CH3CO2)3 described in claim 1 as a raw material in the liquid phase synthesis of various rare earth nanoluminescent materials based on AREF4 (A is one of Na, K, and Li).