Preparation method of disodium dodecahydrogen dodecaboride salt with different degrees of fluorination and its products

Abstract

The present invention provides a preparation method of disodium dodecahydrogen dodecaboride with different degrees of fluorination and its products, belonging to the preparation field of disodium dodecahydrogen dodecaboride. First, Na2B 12 H 12 The mixture is mixed with hydrofluoric acid of a set concentration and heated to react, and the product in the reaction process is condensed and refluxed to obtain a mixture. Then, an alkaline solution or a metal oxide is added to the mixture to perform an acid removal reaction, and the mixture is filtered to obtain a filtrate. Then, the filtrate is purified and eluted to obtain a colorless eluate. Finally, the colorless eluate is evaporated and dried to obtain the fluorinated dodecahydroboron disodium salt product Na2B 12 H 12‑x F x , wherein by adjusting the concentration of hydrofluoric acid, disodium dodecahydrogen dodecaborate with different degrees of fluorination is obtained, and the values ​​of x are 1, 2, 4, 5, 6 or 6. The method of the present invention has readily available raw materials, a simple process, and convenient control, and is suitable for industrial application and promotion.

Description

Technical Field

[0001] The invention belongs to the field of preparation of disodium dodecahydrogen dodecaboride fluoride, and more specifically relates to a preparation method of disodium dodecahydrogen dodecaboride fluoride to different degrees and a product thereof. Background Art

[0002] Sodium-ion batteries (SIBs) have become one of the most attractive and viable battery technologies because sodium is abundant and widely distributed compared to the lithium used in lithium-ion batteries (LIBs). In addition, SIBs can use cheaper and lighter aluminum as the current collector and renewable hard carbon as the anode, thereby reducing the overall cost.

[0003] The main salt used in SIBs' electrolytes is sodium hexafluorophosphate (NaPF6). When exposed to trace amounts of moisture, NaPF6 electrolytes tend to produce hydrofluoric acid (HF). HF accelerates the corrosion of cathode materials and the migration of transition metal compounds from the cathode to the anode, a process that compromises the stability of the solid electrolyte interface (SEI).

[0004] In current technology, Na2B is often used 12 F 12-x H x (also known as disodium dodecahydrogen fluoride dodecaboron) replaces NaPF6 to solve the above problems. Disodium dodecahydrogen fluoride dodecaboron has good thermal stability, electrochemical and moisture stability.

[0005] It has been reported that by reacting Cs2B in supercritical pure HF 12 H 12 Heating to 550°C and holding for 5 hours can produce cesium salt Cs2B with a yield of 38%. 12 F 12 In addition, K2B 12 H 12 When the reaction mixture is heated to 70°C in anhydrous HF and then treated with a mixture of F2 and N2 in a ratio of 20:80 at 25°C, K2B can be obtained. 12 H 12 The fluorinated product of the present invention requires a monel reaction vessel in the preparation method because the F2 / N2 pressure commonly used is 50 psi or higher. However, the above studies all obtained perfluorinated products, and rarely obtained pure partially substituted products.

[0006] The existing technology lacks Na2B 12 F 12-x H x There is no systematic study on how to prepare disodium dodecahydrogen dodecaboron with different degrees of fluorination. Summary of the Invention

[0007] In view of the defects of the prior art, the purpose of the present invention is to provide a preparation method of disodium dodecahydrogen dodecaboride with different degrees of fluorination and its products, so as to make up for the current lack of a preparation method of disodium dodecahydrogen dodecaboride with different degrees of fluorination in the prior art.

[0008] To achieve the above object of the invention, according to the first aspect of the present invention, a method for preparing disodium dodecahydrogen dodecaboron with different degrees of fluorination is provided. First, Na2B 12 H 12 The mixture is mixed with hydrofluoric acid of a set concentration and heated to react. During the reaction, condensation and reflux are performed to obtain a mixture. Then, an alkaline solution or a metal oxide is added to the mixture to perform an acid removal reaction. The mixture is filtered to obtain a filtrate. The filtrate is then purified and eluted to obtain a colorless eluate. Finally, the colorless eluate is evaporated and dried to obtain the fluorinated disodium dodecahydroboron product Na2B 12 H 12-x F x , wherein by adjusting the concentration of hydrofluoric acid, disodium dodecahydrogen dodecaborate with different degrees of fluorination is obtained, and the values ​​of x are 1, 2, 4, 5, 6 or 6 respectively.

[0009] Furthermore, the specific process of purifying and eluting the filtrate is as follows: evaporating the filtrate obtained after deacidification and filtration to obtain a crude product, the crude product is a light yellow solid, dissolving the light yellow solid in a solvent, and collecting the filtrate after filtering again, then evaporating the filtrate collected after filtering again to obtain a solid, dissolving the solid again in the solvent to obtain a mixed liquid to be eluted, and eluting through an elution column to obtain a colorless eluate.

[0010] Furthermore, when the mass fraction of hydrofluoric acid is 40%, the disodium salt of dodecahydroboron fluoride is Na2B 12 H 11 F, the yield is not less than 98%, the hydrofluoric acid is used immediately after being prepared, and the storage time does not exceed 15 minutes.

[0011] Furthermore, when the mass fraction of hydrofluoric acid is 50%, the disodium salt of dodecahydroboron fluoride is Na2B 12 H 10 F2, the yield is not less than 98%, the hydrofluoric acid is used immediately after being prepared, and the storage time does not exceed 15 minutes.

[0012] Furthermore, when the mass fraction of hydrofluoric acid is 60%, the disodium salt of dodecahydroboron fluoride is Na2B 12 H8F4, the yield is not less than 80%, and the hydrofluoric acid is used immediately after preparation, and the storage time does not exceed 15 minutes.

[0013] Furthermore, when the mass fraction of hydrofluoric acid is 70%, the disodium salt of dodecahydroboron fluoride is Na2B 12 H7F5, the yield is not less than 70%, and the hydrofluoric acid is used immediately after preparation, and the storage time does not exceed 15 minutes.

[0014] Furthermore, when the mass fraction of hydrofluoric acid is 80%, the disodium salt of dodecahydroboron fluoride is Na2B 12 H6F6, the yield is not less than 68%, and the hydrofluoric acid is used immediately after preparation, and the storage time does not exceed 15 minutes.

[0015] Furthermore, when the mass fraction of hydrofluoric acid is 90%, the disodium salt of dodecahydroboron fluoride is Na2B 12 H6F6, the yield is not less than 65%, and the hydrofluoric acid is used immediately after preparation, and the storage time does not exceed 15 minutes.

[0016] Furthermore, Na2B 12 H 12 When mixed with hydrofluoric acid of set concentration and heated to react, Na2B 12 H 12 The molar ratio of the reaction mixture to hydrofluoric acid is 1:(15-20), the reaction temperature is 50°C to 80°C, the reaction time is 15 hours to 20 hours, an alkaline solution or a metal oxide is added to the mixture to perform an acid removal reaction, and when the filtrate is obtained by filtration, the alkaline solution is sodium carbonate or sodium bicarbonate solution, and the metal oxide is calcium oxide and / or aluminum oxide. The solvent is acetonitrile, methanol, tetrahydrofuran and / or dimethyl carbonate, and the elution column is made of neutral alumina with a pore size of 40 to 80 mesh.

[0017] According to a second aspect of the present invention, there is also provided a disodium dodecahydrogen dodecaboron salt with different degrees of fluorination obtained by the method as described above.

[0018] In the present invention, the reaction for preparing disodium dodecahydrogen dodecaboron salts with different degrees of fluorination is shown in the following formula: Na2B 12 H 12 +xHF→Na2B 12 H 12 -xF x +xH2.

[0019] In the present invention, Na2B 12 H 12 As raw material for the synthesis of Na2B 12 H 12 -xF xIn the method, the reaction system is liquid, which is convenient for subsequent purification operations; the deacidification and dehydration reactions reduce the impurity content in the reaction product, and the recrystallization process reduces the metal and non-metal ions or compounds in the product, including products produced by side reactions during the fluorination process, thereby greatly improving the purity of the product.

[0020] It should be noted that the hydrofluoric acid used in the method of the present invention is freshly prepared, rather than being sold or purchased on the market. For hydrofluoric acid available on the market, when the concentration of HF exceeds 40%, unsafe incidents may occur during transportation and transshipment. However, for laboratories with complete facilities, hydrofluoric acid of the required concentration can be prepared and used immediately. When the mass fraction of hydrofluoric acid is 100%, it is pure hydrogen fluoride. It is in the form of hydrogen fluoride at room temperature and pressure and can be miscible with water in any proportion. When heated, "white smoke" will emerge, and the "smoke" can be absorbed with water. In actual engineering practice, for example, a condensation reflux device can be used to treat the hydrogen fluoride emitted during the reaction, and it will enter the reaction solution after condensation and reflux. In addition, hydrofluoric acid will corrode glass, and the reaction device needs to be made of stainless steel, polytetrafluoroethylene or PFA.

[0021] In general, the above technical solutions conceived by the present invention have the following advantages compared with the prior art:

[0022] Beneficial effects:

[0023] The synthetic Na2B provided by the present invention 12 H 12-x F x In the method, Na2B 12 H 12 The method uses hydrofluoric acid as raw material to carry out solid-liquid reaction, and then undergoes deacidification reaction, cooling crystallization, and heating water removal to obtain the product. The corrosion-resistant equipment used in this method is relatively easy to obtain, has a simple structure, and has low investment cost, making it suitable for industrial promotion and application. In addition, by simply adjusting the concentration of hydrofluoric acid and the reaction temperature, Na2B with different degrees of fluorination can be obtained. 12 H 12-x F x Therefore, the method of the present invention is a method for preparing disodium dodecahydrogen dodecaboron fluoride with different degrees of fluorination, which has simple process, readily available raw materials, convenient process control and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention provides a flow chart of a method for preparing disodium dodecahydrogen dodecaboron salts with different degrees of fluorination.

[0025] Figure 2 It is the product Na2B of Example 1 of the present invention 12 Structural diagram of H1F.

[0026] Figure 3 This is the 19F nuclear magnetic spectrum of the product of Example 1 of the present invention in deuterated H2O.

[0027] Figure 4 This is the 19F nuclear magnetic spectrum of the product of Example 2 of the present invention in deuterated H2O.

[0028] Figure 5 This is the 19F nuclear magnetic spectrum of the comparative example product of the present invention in deuterated H2O. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0031] Na2B 12 F 12-x H x Has good thermal stability, chemical and moisture stability. Na2B 12 F 12-x H x Compatible with high concentrations of water in the electrolyte. When high concentrations of water up to 10,000 ppm are added to NaPF6-based electrolytes, water reacts with NaPF6 and is rapidly consumed, generating high concentrations of HF in the electrolyte. 12 F 12-x H x The water concentration in the base electrolyte does not change, and even in the presence of 35,000 ppm of water at room temperature, no HF is detected, and this state can be stable for up to 10 days. 12 F 12- x H x Salt has a unique redox shuttling capability that can provide overcharge protection and automatic capacity balancing of sodium-ion batteries when present in a battery pack. 12 F 12 It has a better cycle life than NaPF6.

[0032] The present invention provides a method for preparing disodium dodecahydrogen dodecaboron salts with different degrees of fluorination. The method uses a simple PFA bottle and a condensation reflux device and can obtain a partially fluorinated product by heating under normal pressure by controlling the concentration of hydrofluoric acid.

[0033] First, Na2B 12 H 12 The mixture is heated and reacted with a set concentration, and the product in the reaction process is condensed and refluxed to obtain a mixture. Then, an alkaline solution or a metal oxide is added to the mixture to perform an acid removal reaction, and the mixture is filtered to obtain a filtrate. Then, the filtrate is purified and eluted to obtain a colorless eluate. Finally, the colorless eluate is evaporated and dried to obtain the fluorinated dodecahydroboron disodium salt product Na2B 12 H 12-x F x , wherein, by adjusting the concentration of hydrofluoric acid, different degrees of fluorination of disodium dodecahydroboron are obtained, and the values ​​of x are 1, 2, 4, 5, 6 or 6. The higher the mass fraction of hydrofluoric acid, the higher the product Na2B 12 H 12- x F x The higher the value of x, the higher the degree of fluorination.

[0034] Among them, by adjusting the concentration of hydrofluoric acid, different degrees of fluorination of disodium dodecahydrogen dodecaborate are obtained, and the values ​​of x are 1, 2, 4, 5, 6 or 6. Further, when the mass fraction of hydrofluoric acid is 40%, the fluorinated disodium dodecahydrogen dodecaborate is Na2B 12 H 11 F, the yield is 98%. When the mass fraction of hydrofluoric acid is 50%, the disodium salt of dodecahydroboron fluoride is Na2B 12 H 10 F2, the yield is 98%. When the mass fraction of hydrofluoric acid is 60%, the disodium salt of dodecahydroboron fluoride is Na2B 12 H8F4, the yield is 80%. When the mass fraction of hydrofluoric acid is 70%, the disodium salt of dodecahydroboron fluoride is Na2B 12 H7F5, the yield is 70%. When the mass fraction of hydrofluoric acid is 80%, the disodium salt of dodecahydroboron fluoride is Na2B 12 H6F6, the yield is 68%. Similarly, when the mass fraction of hydrofluoric acid is 90%, the sodium salt of dodecahydroboron fluoride is Na2B 12 H6F6, but the yield is 65%. When the mass fraction of hydrofluoric acid is 80% and 90%, Na2B is obtained. 12 H6F6, it may be because if you want to get more fluorine substitution, the reactant needs a stronger electrophilic attack ability, and the mass fraction of hydrofluoric acid is 90% which is not enough to continue the substitution.

[0035] Among them, Na2B 12 H 12 When mixed with hydrofluoric acid of set concentration and heated to react, the mixture is 12 H 12 The molar ratio of hydrofluoric acid to fluorine is 1:(15-20). Excess hydrofluoric acid promotes the reaction, but excessive hydrofluoric acid contains a high water content, which prolongs subsequent purification. The reaction temperature is 50°C to 80°C. Increasing the temperature accelerates the reaction. If the reaction temperature is too high, the hydrofluoric acid reactant evaporates too quickly, affecting the hydrofluoric acid concentration. The reaction time is 15 to 20 hours. The substitution reaction takes a long time. Analysis of samples taken at regular intervals shows that the reaction results remain essentially unchanged after 15 hours, indicating the completion of the reaction. An alkaline solution or metal oxide is added to the mixture to remove the acid. The filtrate is filtered to obtain the filtrate. The alkaline solution is sodium carbonate or sodium bicarbonate solution. The advantage of using this neutralizing solution is that the reaction is mild and does not introduce new soluble impurities. The products of the acid removal reaction can be removed by filtration. The metal oxide is calcium oxide and / or aluminum oxide. The oxide layer on its surface can bind to positively or negatively charged compounds, thereby achieving separation of the compounds in the mixture. The crude product obtained by the first rotary evaporation is dissolved in a solvent. The solvent can be acetonitrile, tetrahydrofuran, methanol or / and dimethyl carbonate, which can dissolve Na2B well. 12 F 12-x H x Some impurities are separated. Evaporation is carried out by rotary evaporation to remove the solvent in the filtrate. The obtained solid is dissolved in the solvent again and eluted through an elution column containing activated neutral alumina. The elution column is wetted with solvent before use. 12 H 12-x F x When the yellow impurities migrate to 3 / 4 of the length of the elution column, the elution column needs to be replaced, and the colorless eluent is rotary evaporated to dryness to obtain Na2B 12 H 12-x F x Solid product.

[0036] In order to illustrate the method of the present invention in more detail, it is further described in detail below with reference to specific examples.

[0037] Example 1 (Preparation of Na2B 12 H 11 F, x is 1)

[0038] Na2B in this embodiment 12 H 12-x F xThe synthesis method comprises the following steps:

[0039] First, 2g Na2B 12 H 12 The raw materials and 40% hydrofluoric acid liquid were mixed in a PFA reaction bottle at a molar ratio of 1:15, stirred and condensed under reflux. The reaction temperature was 50° C. and the reaction time was 24 h.

[0040] Then, after the reaction is complete, calcium oxide is added to the reaction solution to remove the acid so that the pH of the solution is around 7. The temperature of the deacidification reaction is 50°C.

[0041] The filtrate is then rotary evaporated to obtain a crude product, which is pale yellow. The resulting pale yellow solid is redissolved in acetonitrile and filtered again. After rotary evaporation to remove the filtrate, the resulting solid is redissolved in acetonitrile and passed through an elution column containing activated 60-mesh neutral alumina. The elution column should be pre-wetted with acetonitrile before use. Elution is continued until the yellow impurities migrate to 3 / 4 of the length of the elution column, at which point the column can be replaced with a new one.

[0042] Finally, the colorless eluate was rotary evaporated and dried to obtain the product, which was characterized by 19F nuclear magnetic resonance and the obtained product was Na2B 12 H 11 F, the yield was 98%.

[0043] Figure 2 It is the product Na2B of Example 1 of the present invention 12 H1F structural diagram, Figure 3 This is the 19F NMR spectrum of the product of Example 1 of the present invention in deuterated H2O. Combining the two figures, it can be seen that the product obtained in this example is Na2B 12 H 11 F.

[0044] Example 2 (Preparation of Na2B 12 H 10 F2, x value is 2)

[0045] The synthesis method of this embodiment comprises the following steps:

[0046] First, 1g Na2B 12 H 12 The raw materials and 50% hydrofluoric acid liquid were mixed in a PFA reaction bottle at a molar ratio of 1:15, stirred and condensed under reflux. The reaction temperature was 80° C. and the reaction time was 20 h.

[0047] Then, after the reaction is complete, sodium carbonate solution is added to the reaction solution to remove the acid so that the pH of the solution is about 7. The temperature of the deacidification reaction is 18°C.

[0048] The filtrate is then rotary evaporated to yield a pale yellow crude product. The resulting pale yellow solid is redissolved in acetonitrile and filtered again. After rotary evaporation to remove the filtrate, the resulting solid is redissolved in methanol and passed through a column containing activated 80-mesh neutral alumina. The column is wetted with methanol before use. The product is eluted until the yellow impurities migrate to 3 / 4 of the column length, at which point the column can be replaced with a new one.

[0049] Finally, the colorless eluate was rotary evaporated and dried to obtain the product, which was characterized by 19F nuclear magnetic resonance and the obtained product was Na2B 12 H 10 F2, yield 98%.

[0050] Example 3 (Preparation of Na2B 12 H8F4, x is 4)

[0051] The synthesis method of this embodiment comprises the following steps:

[0052] First, 2g Na2B 12 H 12 The raw materials and 60% hydrofluoric acid liquid were mixed in a PFA reaction bottle at a molar ratio of 1:20, stirred and condensed under reflux. The reaction temperature was 70° C. and the reaction time was 20 h.

[0053] Then, after the reaction is complete, sodium bicarbonate solution is added to the reaction solution to remove the acid so that the pH of the solution is about 7. The temperature of the deacidification reaction is 20°C.

[0054] The filtrate was then subjected to rotary evaporation to obtain a crude product, which was pale yellow. The resulting pale yellow solid was redissolved in acetonitrile and filtered again. After removing the filtrate by rotary evaporation, the resulting solid was redissolved in acetonitrile and passed through a column containing activated 60-mesh neutral alumina, which had been pre-wetted with acetonitrile.

[0055] Finally, the colorless eluate was rotary evaporated and dried to obtain the product, which was characterized by 19F nuclear magnetic resonance and the obtained product was Na2B 12 H8F4, yield 80%.

[0056] Example 4 (Preparation of Na2B 12 H7F5, x is 5)

[0057] The synthesis method of this embodiment comprises the following steps:

[0058] First, 1g Na2B 12 H 12 The raw materials and 70% hydrofluoric acid liquid were mixed in a PFA reaction bottle at a molar ratio of 1:18, stirred and condensed under reflux. The reaction temperature was 70° C. and the reaction time was 20 h.

[0059] Then, after the reaction is complete, sodium bicarbonate solution is added to the reaction solution to remove the acid so that the pH of the solution is about 7. The temperature of the deacidification reaction is 30°C.

[0060] The filtrate was then rotary evaporated to obtain a crude product, which was pale yellow. The resulting pale yellow solid was redissolved in acetonitrile and filtered again. The filtrate was removed by rotary evaporation, and the resulting solid was redissolved in dimethyl carbonate and passed through a column containing activated 40-mesh neutral alumina, which had been pre-wetted with dimethyl carbonate.

[0061] Finally, the colorless eluate was rotary evaporated and dried to obtain the product, which was characterized by 19F nuclear magnetic resonance and the obtained product was Na2B 12 H7F5, yield 70%.

[0062] Figure 4 This is the 19F NMR spectrum of the product of Example 2 of the present invention in deuterated H2O. As can be seen from the figure, it shows that it is Na2B 12 H7F5.

[0063] Example 5 (Preparation of Na2B 12 H6F6, x is 6)

[0064] The synthesis method of this embodiment comprises the following steps:

[0065] First, 1g Na2B 12 H 12 The raw materials and 80% hydrofluoric acid liquid were mixed in a PFA reaction bottle at a molar ratio of 1:18, stirred and condensed under reflux. The reaction temperature was 60° C. and the reaction time was 18 h.

[0066] Then, after the reaction is complete, aluminum oxide solution is added to the reaction solution to remove the acid, so that the pH of the solution is about 7. The temperature of the deacidification reaction is 40°C.

[0067] The filtrate was then rotary evaporated to obtain a crude product, which was pale yellow. The resulting pale yellow solid was redissolved in acetonitrile and filtered again. The filtrate was removed by rotary evaporation, and the resulting solid was redissolved in tetrahydrofuran and passed through a column containing activated 60-mesh neutral alumina, which had been pre-wetted with tetrahydrofuran.

[0068] Finally, the colorless eluate was rotary evaporated and dried to obtain the product, which was characterized by 19F nuclear magnetic resonance and the obtained product was Na2B 12 H6F6, yield 68%.

[0069] Example 6 (Preparation of Na2B 12 H6F6, x is 6)

[0070] The synthesis method of this embodiment comprises the following steps:

[0071] First, 1g Na2B 12 H 12 The raw materials and 90% hydrofluoric acid liquid were mixed in a PFA reaction bottle at a molar ratio of 1:15, stirred and condensed under reflux. The reaction temperature was 80° C. and the reaction time was 18 h.

[0072] Then, after the reaction is complete, sodium carbonate solution is added to the reaction solution to remove the acid, so that the pH of the solution is about 7. The temperature of the deacidification reaction is 45°C.

[0073] The filtrate was then rotary evaporated to obtain a crude product, which was pale yellow. The resulting pale yellow solid was redissolved in acetonitrile and filtered again. The filtrate was removed by rotary evaporation, and the resulting solid was redissolved in acetonitrile and passed through a column containing activated 60-mesh neutral alumina, which had been pre-wetted with CH3CN.

[0074] Finally, the colorless eluate was rotary evaporated and dried to obtain the product, which was characterized by 19F nuclear magnetic resonance and the obtained product was Na2B 12 H6F6, yield 65%.

[0075] Comparative Example

[0076] First, fluorine gas is used to fluorinate Na2B 12 H 12 Specifically, 1 g of the raw material was dissolved in 500 mL of acetonitrile, and 30% fluorine and nitrogen mixed gas was continuously introduced. The reaction was completed after 20 hours.

[0077] Next, sodium bicarbonate solution was added to the reaction solution to remove the acid and adjust the pH of the solution to about 7.

[0078] The filtrate was then subjected to rotary evaporation to obtain a crude product, which was pale yellow. The resulting pale yellow solid was redissolved in acetonitrile and filtered again. The filtrate was removed by rotary evaporation, and the resulting solid was redissolved in acetonitrile and passed through a column containing activated 60-mesh neutral alumina, which had been pre-wetted with acetonitrile.

[0079] Finally, the colorless eluate was rotary evaporated and dried to obtain the product, which was characterized by nuclear magnetic 19F. The main product was NaBF4 with a mass fraction of 90%. It was difficult to obtain Na2B 12 H 12-x F x .

[0080] Figure 5 This is the 19F nuclear magnetic spectrum of the comparative example product of the present invention in deuterated H2O. As can be seen from the figure, the main product is NaBF4.

[0081] In the present invention, the yield is evaluated by the internal standard method, that is, the ratio of the integrated area of ​​the target product in the fluorine spectrum to the internal standard.

[0082] In the above embodiments, the hydrofluoric acid is used immediately after being prepared, and the storage time does not exceed 15 minutes.

[0083] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing disodium dodecahydrogen dodecaboron salts with varying degrees of fluorination, characterized in that: First, Na2B 12 H 12 The mixture is mixed with hydrofluoric acid of a set concentration and heated to react, and the product of the reaction is condensed and refluxed to obtain a mixture. Next, an alkaline solution or a metal oxide is added to the mixture to perform an acid removal reaction, and the mixture is filtered to obtain a filtrate. Then, the filtrate is purified and eluted to obtain a colorless eluate. Finally, the colorless eluate was evaporated to dryness to obtain the fluorinated disodium dodecahydroboron salt product Na2B 12 H 12-x F x , By adjusting the concentration of hydrofluoric acid, disodium dodecahydrogen dodecaboron salts with different degrees of fluorination are obtained, and the values ​​of x are 1, 2, 4, 5, 6 or 6 respectively.

2. The method for preparing disodium dodecahydrogen dodecaboron salts with different degrees of fluorination according to claim 1, characterized in that: The specific process of purifying and eluting the filtrate is as follows: evaporating the filtrate obtained after deacidification and filtration to obtain a crude product, the crude product is a light yellow solid, dissolving the light yellow solid in a solvent, filtering again and collecting the filtrate, then evaporating the filtrate collected after filtering again to obtain a solid, dissolving the solid again in the solvent to obtain a mixed liquid to be eluted, and eluting through an elution column to obtain a colorless eluent.

3. The method for preparing disodium dodecahydrogen dodecaboron salts with different degrees of fluorination according to claim 1, characterized in that: When the mass fraction of hydrofluoric acid is 40%, disodium dodecahydrofluoride dodecaboron is Na2B 12 H 11 F, the yield is not less than 98%, the hydrofluoric acid is used immediately after being prepared, and the storage time does not exceed 15 minutes.

4. The method for preparing disodium dodecahydrogen dodecaboron salts with different degrees of fluorination according to claim 1, wherein: When the mass fraction of hydrofluoric acid is 50%, the disodium salt of dodecahydroboron fluoride is Na2B 12 H 10 F2, the yield is not less than 98%, the hydrofluoric acid is used immediately after being prepared, and the storage time does not exceed 15 minutes.

5. The method for preparing disodium dodecahydrogen dodecaboron salts with different degrees of fluorination according to claim 1, wherein: When the mass fraction of hydrofluoric acid is 60%, the disodium salt of dodecahydroboron fluoride is Na2B 12 H8F4, the yield is not less than 80%, and the hydrofluoric acid is used immediately after preparation, and the storage time does not exceed 15 minutes.

6. The method for preparing disodium dodecahydrogen dodecaboron salts with different degrees of fluorination according to claim 1, characterized in that: When the mass fraction of hydrofluoric acid is 70%, disodium dodecahydroboron fluoride is Na2B 12 H7F5, the yield is not less than 70%, and the hydrofluoric acid is used immediately after preparation, and the storage time does not exceed 15 minutes.

7. The method for preparing disodium dodecahydrogen dodecaboron salts with different degrees of fluorination according to claim 1, characterized in that: When the mass fraction of hydrofluoric acid is 80%, the disodium salt of dodecahydroboron fluoride is Na2B 12 H6F6, the yield is not less than 68%, and the hydrofluoric acid is used immediately after preparation, and the storage time does not exceed 15 minutes.

8. The method for preparing disodium dodecahydrogen dodecaboron salts with different degrees of fluorination according to claim 1, wherein: When the mass fraction of hydrofluoric acid is 90%, the disodium salt of dodecahydroboron fluoride is Na2B 12 H6F6, the yield is not less than 65%, and the hydrofluoric acid is used immediately after preparation, and the storage time does not exceed 15 minutes.

9. A method for preparing a disodium salt of dodecahydrogen dodecaboron with different degrees of fluorination according to any one of claims 2 to 8, characterized in that: Na2B 12 H 12 When mixed with hydrofluoric acid of set concentration and heated to react, Na2B 12 H 12 The molar ratio of fluorine to hydrofluoric acid is 1: (15-20), the reaction temperature is 50 ℃ ~ 80 ℃, and the reaction time is 15h ~ 20h. An alkaline solution or a metal oxide is added to the mixture to perform an acid removal reaction. When the filtrate is obtained by filtration, the alkaline solution is a sodium carbonate or sodium bicarbonate solution, the metal oxide is calcium oxide and / or aluminum oxide, and the temperature of the acid removal reaction is 18° C. to 50° C. The solvent is acetonitrile, tetrahydrofuran and / or dimethyl carbonate, and the elution column is made of neutral alumina with a pore size of 40-80 meshes.

10. Disodium dodecahydrogen dodecaboron salts with varying degrees of fluorination obtained by the method of claim 9.

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