An apparatus and method for the rapid preparation of anhydrous trihalogenide in the laboratory

Abstract

This invention discloses an apparatus and method for the rapid preparation of anhydrous trihalides in the laboratory, belonging to the field of anhydrous rare earth halides preparation technology. The apparatus includes a circulating water pump, a dehydrating agent conical flask, a tube furnace, a chloride conical flask, and an aqueous conical flask. The aqueous conical flask is connected to one end of the chloride conical flask via a rubber tube, and the other end of the chloride conical flask is connected to the tube furnace via a rubber tube. The end of the tube furnace furthest from the chloride conical flask is connected to one end of the dehydrating agent conical flask via a rubber tube, and the other end of the dehydrating agent conical flask is connected to one end of the circulating water pump via a rubber tube. This invention utilizes the dehydrating agent in the dehydrating agent conical flask and the circulating water pump to maintain a vacuum during the halide preparation process, while simultaneously preventing the deliquescence reaction between airborne water and oxygen and the rare earth halides, resulting in fewer impurities and higher purity in the halides.

Description

Technical Field

[0001] This invention belongs to the field of preparation technology of anhydrous rare earth halides, specifically relating to an apparatus and method for rapid preparation of anhydrous trihalides in the laboratory. Background Technology

[0002] Anhydrous rare earth halides are important raw materials in the manufacturing industry, with significant and broad application prospects in fields such as luminescent materials, thermal insulation materials, hydrogen storage materials, ceramic materials, catalysis, and military applications. However, due to the highly hygroscopic nature of rare earth halides, the preparation of anhydrous rare earth halides easily generates large amounts of halide oxides and oxides as impurities, making the preparation of anhydrous rare earth halides extremely difficult and costly.

[0003] Currently, the existing technology for preparing anhydrous rare earth halides mainly involves dehydrating hydrated rare earth halides. Existing technologies for dehydrating hydrated rare earth halides include: (1) direct heating in air; (2) heating under inert atmosphere or vacuum conditions; (3) heating under ammonium halide protection; and (4) heating under hydrogen halide gas protection. Direct heating in air allows water and oxygen to easily react with the rare earth halides, resulting in anhydrous rare earth halides containing a large amount of halide oxides and oxide impurities. To address the problem of deliquescence and oxidation, existing technologies involve dehydration under a protective atmosphere or vacuum, and by strictly controlling the heating rate and temperature range, deliquescence can be suppressed to some extent. However, all these existing technologies suffer from unsatisfactory dehydration effects and severe hydrolysis, resulting in anhydrous rare earth halides prepared in my country that are not only of poor purity but also complex and costly to produce.

[0004] A method for preparing anhydrous rare earth halides is disclosed in patent publication number CN113830818A, comprising the following steps: S1: dissolving a hydrated rare earth halide containing water of crystallization in an ethanol solution to obtain a rare earth alcohol solution; S2: heating the rare earth alcohol solution once while simultaneously distilling under reduced pressure to evaporate and remove the ethanol in the solution to obtain a rare earth solution; S3: heating an ammonium halide to allow the rare earth solution to undergo a second heating and dehydration in the atmosphere of the gas generated during the heating of the ammonium halide, and after dehydration, cooling to room temperature to obtain anhydrous rare earth halides, which are then removed and packaged.

[0005] The dehydration effect of the above-mentioned patent for preparing anhydrous rare earth halides is poor and there is still a serious hydrolysis problem. Therefore, how to provide an apparatus and method for rapidly preparing anhydrous trihalides in the laboratory is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] The main objective of this invention is to provide an apparatus and method for the rapid preparation of anhydrous trihalides in the laboratory, thereby solving the aforementioned technical problems. This apparatus utilizes a dehydrating agent in a conical flask and a circulating water pump to maintain a vacuum during the halide preparation process, while simultaneously preventing the deliquescence reaction between airborne water and oxygen and the rare earth halides, resulting in fewer impurities and higher purity in the halides.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An apparatus for the rapid preparation of anhydrous trihalides in the laboratory includes a circulating water pump, a dehydrating agent conical flask, a tube furnace, a chloride conical flask, and an aqueous conical flask. The aqueous conical flask is connected to one end of the chloride conical flask via a rubber tube, and the other end of the chloride conical flask is connected to the tube furnace via a rubber tube. The end of the tube furnace away from the chloride conical flask is connected to one end of the dehydrating agent conical flask via a rubber tube, and the other end of the dehydrating agent conical flask is connected to one end of the circulating water pump via a rubber tube.

[0009] Furthermore, a two-way valve is installed on the rubber tube connecting the dehydrating agent conical flask and the circulating water pump, and a two-way valve is installed on the rubber tube connecting the water-containing conical flask and the chloride conical flask.

[0010] Furthermore, the dehydrating agent in the dehydrating agent conical flask is concentrated sulfuric acid, and the chloride in the chloride conical flask is anhydrous calcium chloride.

[0011] A method using an apparatus for the rapid preparation of anhydrous trihalides in a laboratory includes the following steps:

[0012] S1. Turn on the circulating water pump in advance to absorb the air in the beaker and evacuate the conical flask to a vacuum. This operation must be carried out under oxygen-free conditions. After evacuating to a vacuum, turn off the circulating water pump and then clamp the rubber tube with a clamp to prevent oxygen from re-entering and to ensure the vacuum level of the experimental environment.

[0013] S2, grind NH4Cl and La2O3 in a mortar in a stoichiometric ratio until they are thoroughly mixed. Then, place this mixture in a quartz tube in a tube furnace and heat it in the tube furnace at 200°C under near vacuum for 10 hours. Then, under nitrogen protection, raise the temperature to 600°C and hold it at this temperature for 5 hours to remove unreacted NH4Cl and generate LaCl3.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] This invention utilizes the dehydrating agent in the conical flask and the circulating water pump to maintain a vacuum during the preparation of halides, while avoiding the deliquescence reaction between water and oxygen in the air and rare earth halides, resulting in fewer impurities and higher purity in the halides. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of the present invention.

[0018] Among them, 1-circulating water pump, 2-two-way valve, 3-dehydrating agent conical flask, 4-tube furnace, 5-hydrated rare earth halide conical flask, 6-water-containing conical flask, 7-two-way valve II. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1 As shown, this invention provides an apparatus for the rapid preparation of anhydrous trihalides in the laboratory, comprising a circulating water pump 1, a dehydrating agent conical flask 3, a tube furnace 4, a chloride conical flask 5, and an aqueous conical flask 6. The aqueous conical flask 6 is connected to one end of the chloride conical flask 5 via a rubber tube, and the other end of the chloride conical flask 5 is connected to the tube furnace 4 via a rubber tube. The end of the tube furnace 4 furthest from the chloride conical flask 5 is connected to one end of the dehydrating agent conical flask 3 via a rubber tube, and the other end of the dehydrating agent conical flask 3 is connected to one end of the circulating water pump 1 via a rubber tube. The circulating water pump 1 is used to ensure the apparatus... The vacuum degree of the device; the dehydrating agent in the conical flask 3 is concentrated sulfuric acid, which is used to prevent the formation of water and maintain a dry environment, and is directly connected to the vacuum circulating water pump to provide a vacuum environment; the tube furnace 4 is the experimental reaction device, which is used to provide temperature for the experiment. The heating rate of the tube furnace 4 can be adjusted and can also be adjusted and controlled during theoretical calculations. At the same time, the tube furnace 4 conducts orthogonal experimental design of the generation of related chemical reactions at different temperatures to determine which condition yields the highest yield; the anhydrous calcium chloride and water in the chloride conical flask 5 and the aqueous conical flask 6 are used to treat the tail gas.

[0021] In this embodiment, a two-way valve 2 is provided on the rubber tube connecting the dehydrating agent conical flask 3 and the circulating water pump 1, and a two-way valve 7 is provided on the rubber tube connecting the water-containing conical flask 6 and the chloride conical flask 5. The two-way valve 2 and the two-way valve 7 are used to control the flow and closure of the rubber tube.

[0022] In this embodiment, the dehydrating agent in the conical flask 3 is concentrated sulfuric acid, used to prevent the formation of moisture, and the chloride in the conical flask 5 is anhydrous calcium chloride, used to treat the exhaust gas.

[0023] A method using an apparatus for the rapid preparation of anhydrous trihalides in a laboratory includes the following steps:

[0024] S1. Turn on the circulating water pump 1 in advance to absorb the air in the beaker and evacuate the conical flask to a vacuum. This operation must be carried out under oxygen-free conditions. After evacuating to a vacuum, turn off the circulating water pump 1 and then clamp the rubber tube with a clamp to prevent oxygen from entering again and to ensure the vacuum level of the experimental environment.

[0025] S2, grind NH4Cl and La2O3 in a mortar in a stoichiometric ratio until they are thoroughly mixed. Then, place this mixture in a quartz tube in a tube furnace 4 and heat it in the tube furnace 4 at 200°C under near vacuum for 10 hours. Then, under nitrogen protection, raise the temperature to 600°C and hold it at this temperature for 5 hours to remove unreacted NH4Cl and generate LaCl3.

[0026] Theoretical design calculation

[0027] This apparatus uses anhydrous LaCl3 chloride as an example to illustrate the theoretical design and calculations. It can represent the formation process of lanthanide chlorides (they have similar chemical properties, form a separate series, and occupy a special position in the periodic table. The lanthanides (La), scandium (Sc), and yttrium (Y), a total of 17 elements, are collectively called rare earth elements (RE). La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Pm (promethium), Sm (samarium), and Eu (europium) are called cerium group rare earths (light rare earths); Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium), Lu (lutetium), Sc, and Y are called yttrium group rare earths (medium and heavy rare earths)). In this experiment, LaCl3 powder was prepared using the ammonium chloride chlorination method. As mentioned earlier, the experimental preparation process is shown below, and the chemical equation for the reaction is shown below.

[0028] La2O3+6NH4Cl=2LaCl3(s)+3H2O(g)↑

[0029] The main raw materials include lanthanum oxide (La₂O₃, with a purity of 99.99%, by mass fraction) and ammonium chloride (NH₄Cl, analytical grade). First, the materials were weighed according to their composition. Multiple parallel experiments were conducted under different experimental conditions to perform the relevant experimental operations.

[0030] Option 1: Weigh 2.5 mmol La₂O₃ (approximately 0.8142 g) and 30 mmol NH₄Cl (approximately 1.6054 g). From a cost perspective, experimental analysis shows that the mass of NH₄Cl should be significantly greater than that of La₂O₃. This is because lanthanide oxides are expensive and difficult to obtain. Therefore, ensuring complete reaction of La₂O₃ is crucial. Theoretical calculations show that 5 mmol of anhydrous LaCl₃ (approximately 1.2263 g) can be generated. A circulating water pump 1 creates an oxygen-free environment inside the preparation apparatus. After grinding the solid with a grinding rod, it is placed into the tube furnace 4. In a tube furnace, the total mass of the mixture of La₂O₃ and NH₄Cl was weighed to be 2.4407 g. After adjusting the vacuum level to within the planned range, the furnace was placed in tube furnace 4 for a variable-temperature experiment. The temperature was initially set to 200°C. After two hours of reaction, the temperature was increased to 250°C. After one hour of reaction, the temperature of tube furnace 4 was set to 450°C. After one hour of reaction, the program was adjusted to the end, and the experiment was terminated. This reaction ensured that the two reactants reacted completely and uniformly, and that the reaction was carried out under anaerobic conditions. After the reaction, the mass of the obtained solid was weighed to be 0.9445 g. The yield of this experiment was calculated to be...

[0031]

[0032] Option 2: Weigh 5.0 mmol La₂O₃ (approximately 1.6162 g) and 60 mmol NH₄Cl (approximately 3.2187 g). Based on cost considerations, theoretical calculations show that 20 mmol of anhydrous LaCl₃ (approximately 2.4526 g) can be generated. A circulating water pump 1 creates an oxygen-free environment inside the preparation apparatus. After grinding the solid with a grinding rod, it is placed in a quartz tube within a tube furnace 4. The vacuum level is adjusted to the planned range, and the apparatus is then placed in tube furnace 1 for the experiment. The temperature is set to 600℃, and the reaction is carried out for 16 hours. The previous experimental setup is then removed, and high-purity N₂ is introduced to continue the reaction at a flow rate of 50 mL / min. Nitrogen acts as a protective gas. The program is adjusted to program-121, and the total reaction time is 2.5 hours. The experiment was then terminated. This reaction ensured that the two reactants reacted completely and uniformly, and that the reaction was carried out under anaerobic conditions. After the reaction, the mass of the obtained solid was weighed and found to be 1.7503 g. The yield of this experiment was calculated to be...

[0033]

[0034] Orthogonal experiments were designed, experiments were conducted under different experimental conditions, and the results were analyzed and processed. The experimental results were then processed and analyzed, and the substances under different experimental conditions were analyzed. Multiple repeated experiments were performed to obtain the corresponding experimental data.

[0035] Performance Testing and Analysis

[0036] Through a series of experimental operations, newly prepared anhydrous LaCl3 can be obtained, and its performance indicators can be judged by calculating its purity and other factors. The purity test of anhydrous LaCl3 is mainly determined by the Mohr method and the gravimetric method.

[0037] The Mohr method is a commonly used argentometric titration method in precipitation titration for determining the titration endpoint. It involves directly titrating chloride (or bromide) ions with a standard silver nitrate solution in a neutral or weakly alkaline solution using potassium chromate as an indicator. Based on the principle of stepwise precipitation, AgCl precipitate is initially formed. As silver nitrate is added, the chloride ion concentration decreases, while the silver ion concentration increases accordingly. The appearance of a brick-red silver chromate precipitate indicates the titration endpoint. The Mohr method can be used to standardize the precipitation of chloride ions that form halides. - and Br - The molar concentration of the substance is determined step by step to calculate the relevant concentrations in the experiment.

[0038] Gravimetric analysis is an analytical method that determines the content of a component in a substance by weighing it. In this process, the component to be analyzed is typically separated from the sample using an appropriate method, converted into a specific weighable form, and then weighed. The content of the component is then calculated from the obtained mass.

[0039] This experiment uses the following two experimental methods to further analyze the purity.

[0040] As shown in Scheme 1 above, taking one type of chloride as the main example, the final weight of the solid obtained is 0.9445g. 0.5037g of this solid is weighed out and dissolved in 250mL of anhydrous LaCl3. 25mL of this solution is then added to sufficient AgNO3 solution to initiate a chemical reaction. The chemical reaction equation is shown below:

[0041] AgNO3 + LaCl3 = AgCl↓ (white) + LaNO3

[0042] Ionic reaction: Ag + +Cl - =AgCl↓ (white)

[0043] After the chemical reaction is complete and no new white precipitate appears in the solution, let the beaker stand to allow the lower precipitate to completely separate from the supernatant. Discard the supernatant, leaving the lower precipitate. Filter the precipitate, dry it in an oven, and weigh the final precipitate. The obtained mass is 0.0872g, which is 1 / 10 of the total mass taken out. Therefore, the calculated purity is...

[0044]

[0045] By enumerating the methods, the production method of high-purity anhydrous LaCl3 is derived. Similarly, the theoretical calculation methods for other anhydrous halides and the relevant tests and analyses of their properties can be obtained, thus leading to relevant conclusions.

[0046] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0047] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for the rapid preparation of anhydrous trihalogenide in the laboratory, characterized in that, The system includes a circulating water pump (1), a dehydrating agent conical flask (3), a tubular furnace (4), a chloride conical flask (5), and an aqueous conical flask (6). The aqueous conical flask (6) is connected to one end of the chloride conical flask (5) via a rubber tube. The other end of the chloride conical flask (5) is connected to the tubular furnace (4) via a rubber tube. The end of the tubular furnace (4) away from the chloride conical flask (5) is connected to one end of the dehydrating agent conical flask (3) via a rubber tube. The other end of the dehydrating agent conical flask (3) is connected to one end of the circulating water pump (1) via a rubber tube. A two-way valve (2) is provided on the rubber tube connecting the dehydrating agent conical flask (3) and the circulating water pump (1), and a two-way valve (7) is provided on the rubber tube connecting the water-containing conical flask (6) and the chloride conical flask (5); The dehydrating agent in the dehydrating agent conical flask (3) is concentrated sulfuric acid, and the chloride in the chloride conical flask (5) is anhydrous calcium chloride.

2. A method for the rapid preparation of anhydrous trihalogenide in a laboratory, using the apparatus according to claim 1, characterized in that Includes the following steps: S1, turn on the circulating water pump (1) in advance to absorb the air in the beaker, evacuate the conical flask to a vacuum. This operation must be carried out under oxygen-free conditions. After evacuating to a vacuum, turn off the circulating water pump (1) and then clamp the rubber tube with a clamp to prevent oxygen from entering again and ensure the vacuum level of the experimental environment. S2, grind NH4Cl and La2O3 in a mortar in a 2:1 ratio until they are thoroughly mixed. Then, place the mixture in a quartz tube in a tube furnace (4) and heat it in the tube furnace (4) at 200°C under vacuum for 10 hours. Then, raise the temperature to 600°C under nitrogen protection and hold it at this temperature for 5 hours to remove unreacted NH4Cl and generate LaCl3.

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