A process for the preparation of a complex

Abstract

The application discloses a preparation method of a complex, and relates to the technical field of boron trifluoride production, and comprises the following steps: S1, vaporizing a ketone intermediate and mixing the ketone intermediate with boron trifluoride gas to perform a complexing reaction, so as to obtain a ketone-boron trifluoride complex; S2, adding diethyl ether drop by drop into the ketone-boron trifluoride complex to perform a coordination reaction, and obtaining a reaction mixture after the reaction is completed; and S3, washing, filtering and evaporating and drying the reaction mixture to obtain a boron trifluoride-diethyl ether complex. According to the preparation method, the intermediate complex is prepared first, and then the boron trifluoride-diethyl ether complex is prepared through a coordination reaction, so that the generation of impurities is reduced, the purity of a product is improved, the operation is safer, the stability of boron trifluoride is protected in the reaction process, and the volatilization and loss of boron trifluoride are reduced.

Description

Technical Field

[0001] This invention relates to the field of boron trifluoride production technology, and more specifically to a method for preparing a complex. Background Technology

[0002] Boron-10 acid, also known as boron-10 isotope, is a white, powdery crystalline or flaky, lustrous crystal. Its natural purity is 19.4%, and it possesses strong neutron absorption and radiation protection properties. Boron-10 acid typically exists as a boron trifluoride-diethyl ether complex or as a solid 10B, H310BO3. Benefiting from its powerful radiation protection and thermal neutron absorption capabilities, as well as continuous breakthroughs in boron-10 acid processing technology, it has found widespread application in nuclear radiation shielding in nuclear power generation, energy supply in the defense industry, and neutron protection.

[0003] In the field of nuclear power generation, boron-10 acid can be directly applied to nuclear power plants as a preferred chemical compensation control agent to ensure the efficient and safe neutron shielding function of the reactor cooling system, thereby effectively improving the safety, flexibility, and service life of the nuclear power plant. Furthermore, boron-10 acid can also serve as a core raw material for reactor control rods to improve the level of reactor reaction intensity control. In addition, as a neutron shielding material, boron-10 acid can also be used for nuclear waste storage and transportation, effectively preventing nuclear proliferation and making nuclear waste disposal more efficient, safe, and reliable.

[0004] In the defense field, boron-10 acid is an ideal material for reactor control and radiation shielding in nuclear power plants such as nuclear submarines and nuclear aircraft carriers. On the other hand, boron-10 acid can be combined with other materials such as iron, aluminum, and polyethylene to manufacture boron-10 steel and boron-10 fiber. Furthermore, boron-10 steel can be used to produce armor, and boron-10 fiber can be used to produce nuclear radiation protective clothing and neutron protective clothing to ensure the energy supply of defense equipment and the safety of related operators.

[0005] Existing methods for preparing boron trifluoride-diethyl ether complexes often involve direct contact between boron fluoride gas and liquid diethyl ether to induce a complexation reaction. This results in a low purity of the prepared boron trifluoride-diethyl ether complex, around 90%. To improve the capture rate of boron fluoride gas by diethyl ether, it is first vaporized before gas-phase complexation. However, the vaporization of diethyl ether is highly hazardous. Diethyl ether is a volatile liquid with a low boiling point (approximately 34.6 degrees Celsius). It can rapidly vaporize into flammable vapor, forming a flammable gas-air mixture, and under suitable conditions, an explosive mixture. Therefore, this operation poses a significant safety hazard. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a method for preparing complexes, thereby solving the technical problems of low purity and high risk of preparation methods of boron trifluoride-diethyl ether complexes in the prior art.

[0007] To achieve the above-mentioned technical objectives, the present invention provides a method for preparing a complex, comprising the following steps;

[0008] S1; Mix potassium fluoroborate and boron anhydride, add concentrated sulfuric acid, and stir continuously. After stirring evenly, gradually heat the mixture. During the heating process, gas is gradually generated. Heat the mixture to 95-120℃ until no more gas is generated, and collect the generated boron trifluoride gas.

[0009] The chemical reaction equation for this process is as follows:

[0010] 6KBF4+B2O3+6H2SO4→8BF3+6KHSO4+3H2O

[0011] S2. The ketone intermediate is vaporized and mixed with boron trifluoride gas to carry out a complexation reaction to obtain a ketone-boron trifluoride complex. The temperature of the complexation reaction is -20 to 0℃. The molar ratio of boron trifluoride to ketone intermediate is 1.1-1.2:1. Excess boron trifluoride can promote the reaction, but excessive use should be avoided to reduce the occurrence of side reactions.

[0012] Boron trifluoride (BF3) is a strong Lewis acid with empty orbitals capable of accepting electron pairs. The ketone intermediate contains a basic hydrogen atom on the active α-carbon. In the reaction, boron trifluoride undergoes a complexation reaction with the ketone intermediate, where the empty orbital of one boron trifluoride molecule forms a new chemical bond with the basic hydrogen atom of the ketone intermediate.

[0013] The ketone intermediate is one of acetone, methyl isopropanone, aromatic ketone, or α,β-unsaturated ketone.

[0014] The structure of ketones plays a key role in their ability to capture boron trifluoride gas. To enhance the ability of ketone intermediates to capture boron trifluoride gas, electrophilic ketone structures, such as aromatic ketones and α,β-unsaturated ketones, with strong electron-attracting groups or conjugated structures, can be selected, which have higher affinity and reactivity for boron trifluoride gas.

[0015] For example, the ketone intermediates mentioned are α,β-unsaturated ketones. These ketone compounds can react with boron trifluoride to form ketone boron trifluoride complexes. Ensure that the selected ketone intermediates have sufficient purity and structural characteristics.

[0016] S3. The diethyl ether is added dropwise to the ketone-boron trifluoride complex to carry out a coordination reaction. After the reaction is completed, a reaction mixture (crude product of boron trifluoride-diethyl ether complex) is obtained.

[0017] In this step, the ketone-boron trifluoride complex diethyl ether (Et₂O) undergoes a coordination reaction. The oxygen atom of diethyl ether has a lone pair of electrons, which can form a strong coordinate bond with BF₃. This coordination reaction forms a stable complex, in which BF₃ and diethyl ether form a new chemical bond through the coordination of the oxygen atom, and form a stable complex, the boron trifluoride-diethyl ether complex (BF₃·Et₂O).

[0018] To enhance the reactivity of the coordination reaction between BF3 and diethyl ether, the molar ratio of diethyl ether to the ketone-boron trifluoride complex in the coordination reaction is 5-7:1, and the reaction temperature is -10 to 0℃.

[0019] Triethylamine and / or alkali metal salts can be added to enhance the ability of diethyl ether to abstract boron trifluoride from the boron trifluoride-ketone complex. The amount of triethylamine and / or alkali metal salt added is 1.5-2% of the molar amount of the reaction substrate. Triethylamine and / or alkali metal salts can provide active sites or promote coordination reactions, strengthen the interaction between boron trifluoride and diethyl ether in the complex, promote the formation of the boron trifluoride-diethyl ether complex, and improve the purity of the product.

[0020] S3. The reaction mixture is washed, filtered, and evaporated to dryness to obtain boron trifluoride-diethyl ether complex. The structural formula of the obtained boron trifluoride-diethyl ether complex is as follows;

[0021]

[0022] Compared with the prior art, the beneficial effects of the present invention include: the preparation method of the present invention first prepares an intermediate complex, and then prepares a boron trifluoride-diethyl ether complex through a coordination reaction, using a ketone as an intermediate. The carbonyl functional group (C=O) in the ketone molecule has a high affinity and selectivity for boron trifluoride molecules, and reacts with boron fluoride to form a stable complex. In the method of direct complexation of boron fluoride and diethyl ether, diethyl ether may compete with other reactants or byproducts when directly complexing with boron fluoride, resulting in high impurities in the product. By using a ketone as an intermediate, the selectivity of the product can be improved, the generation of impurities can be reduced, and thus the product can be improved. High product purity; acetone has a lower vaporization hazard and a relatively high boiling point (approximately 56.5 degrees Celsius). Compared to diethyl ether, acetone is less flammable, making the vaporization reaction relatively safer; choosing a more electrophilic ketone structure enhances the ability of the ketone intermediate to capture boron fluoride, while adding triethylamine and / or alkali metal salts provides more active sites or promotes coordination reactions, facilitating the formation of the boron fluoride diethyl ether complex and improving the overall yield; the carbonyl functional group in acetone can form a weak complex with boron fluoride, and its stability can be enhanced in subsequent reactions by reacting with stronger complexing agents such as diethyl ether. This helps protect the stability of boron fluoride during the reaction, reducing volatilization and loss. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] Example 1

[0025] This embodiment provides a method for preparing a complex, including the following steps;

[0026] S1; Mix potassium fluoroborate and boron anhydride, add concentrated sulfuric acid, and stir continuously. After stirring evenly, gradually heat the mixture. During the heating process, gas is gradually generated. Heat the mixture to 95°C until no more gas is generated, and collect the generated boron trifluoride gas.

[0027] S2. Acetone is vaporized and mixed with boron trifluoride gas to carry out a complexation reaction to obtain a ketone-boron trifluoride complex. The temperature of the complexation reaction is -20°C. The molar ratio of boron trifluoride to ketone intermediate is 1.1:1. Excess boron trifluoride can promote the reaction, but excessive use should be avoided to reduce the occurrence of side reactions.

[0028] S3. The diethyl ether is added dropwise to the ketone-boron trifluoride complex to carry out a coordination reaction. After the reaction is completed, a reaction mixture is obtained. The molar ratio of diethyl ether to ketone-boron trifluoride complex in the coordination reaction is 5:1, and the reaction temperature of the coordination reaction is -10℃.

[0029] S3. The reaction mixture is washed, filtered, and evaporated to dryness to obtain boron trifluoride-diethyl ether complex.

[0030] Example 2

[0031] This embodiment provides a method for preparing a complex, including the following steps;

[0032] S1; Mix potassium fluoroborate and boron anhydride, add concentrated sulfuric acid, and stir continuously. After stirring evenly, gradually heat the mixture. During the heating process, gas is gradually generated. Heat the mixture to 120°C until no more gas is generated, and collect the generated boron trifluoride gas.

[0033] S2. Methyl isopropanone is vaporized and mixed with boron trifluoride gas to carry out a complexation reaction to obtain a ketone-boron trifluoride complex. The temperature of the complexation reaction is 0°C, and the molar ratio of boron trifluoride to ketone intermediate is 1.2:1.

[0034] S3. The diethyl ether is added dropwise to the ketone-boron trifluoride complex, followed by the addition of an alcohol-alkali metal salt to carry out a coordination reaction. After the reaction is completed, a reaction mixture (crude product of boron trifluoride-diethyl ether complex) is obtained. The molar ratio of diethyl ether to ketone-boron trifluoride complex in the coordination reaction is 7:1, and the reaction temperature of the coordination reaction is 0℃.

[0035] S3. The reaction mixture is washed, filtered, and evaporated to dryness to obtain boron trifluoride-diethyl ether complex.

[0036] Example 3

[0037] This embodiment provides a method for preparing a complex, including the following steps;

[0038] S1; Mix potassium fluoroborate and boron anhydride, add concentrated sulfuric acid, and stir continuously. After stirring evenly, gradually heat the mixture. During the heating process, gas is gradually generated. Heat the mixture to 100°C until no more gas is generated, and collect the generated boron trifluoride gas.

[0039] S2. After vaporizing benzophenone, it is mixed with boron trifluoride gas to carry out a complexation reaction to obtain a ketone-boron trifluoride complex. The temperature of the complexation reaction is -10℃, and the molar ratio of boron trifluoride to ketone intermediate is 1.15:1.

[0040] S3. The diethyl ether is added dropwise to the ketone-boron trifluoride complex, followed by triethylamine, to carry out a coordination reaction. After the reaction is completed, a reaction mixture (crude product of boron trifluoride-diethyl ether complex) is obtained. The molar ratio of diethyl ether to ketone-boron trifluoride complex in the coordination reaction is 6:1, and the reaction temperature of the coordination reaction is -5℃.

[0041] S3. The reaction mixture is washed, filtered, and evaporated to dryness to obtain boron trifluoride-diethyl ether complex.

[0042] Example 4

[0043] This embodiment provides a method for preparing a complex, including the following steps;

[0044] S1; Mix potassium fluoroborate and boron anhydride, add concentrated sulfuric acid, and stir continuously. After stirring evenly, gradually heat the mixture. During the heating process, gas is gradually generated. Heat the mixture to 106°C until no more gas is generated, and collect the generated boron trifluoride gas.

[0045] S2. The α,β-unsaturated ketone (3-penten-2-one) is vaporized and mixed with boron trifluoride gas to carry out a complexation reaction to obtain a ketone-boron trifluoride complex. The temperature of the complexation reaction is -7°C. The molar ratio of boron trifluoride to ketone intermediate is 1.2:1. Excess boron trifluoride can promote the reaction, but excessive use should be avoided to reduce the occurrence of side reactions.

[0046] S3. The diethyl ether is added dropwise to the ketone-boron trifluoride complex, followed by the addition of an alcohol-alkali metal salt to carry out a coordination reaction. After the reaction is completed, a reaction mixture (crude product of boron trifluoride-diethyl ether complex) is obtained. The molar ratio of diethyl ether to ketone-boron trifluoride complex in the coordination reaction is 5:1, and the reaction temperature of the coordination reaction is 0℃.

[0047] S3. The reaction mixture is washed, filtered, and evaporated to dryness to obtain boron trifluoride-diethyl ether complex.

[0048] Comparative Example

[0049] In this comparative example, boron fluoride gas was directly passed into diethyl ether liquid to prepare boron fluoride diethyl ether complex.

[0050] The yields and purities of the boron trifluoride-diethyl ether complexes prepared in Examples 1 to 4 and the comparative examples were calculated, and the measurement results are shown in Table 1 below;

[0051] Table 1. Statistical results of yield and purity of boron trifluoride-diethyl ether complex.

[0052] Example 1 92.1 99.54 Example 2 93.9 99.71 Example 3 93.7 99.73 Example 4 94 99.81 Comparative Example 76.4 88.43

[0053] The data in the table clearly show that the overall yield of the preparation method of the present invention is higher than that of the preparation method in the prior art. Comparing the data in Example 1 and Examples 2-4, it can be seen that adding triethylamine and alkali metal salts can improve the reaction activity to a certain extent, and improve the yield and the purity of the final product.

[0054] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a complex, characterized in that, Includes the following steps; S1. The ketone intermediate is vaporized and mixed with boron trifluoride gas to carry out a complexation reaction to obtain a ketone-boron trifluoride complex; wherein the ketone intermediate is one of acetone, methyl isopropanone, aromatic ketone, or α,β-unsaturated ketone, and the molar ratio of boron trifluoride to the ketone intermediate is 1.1-1.2:

1. S2. Diethyl ether is added dropwise to the ketone-boron trifluoride complex, and triethylamine and / or an alcohol-alkali metal salt are also added to carry out a coordination reaction. After the reaction is completed, a reaction mixture is obtained. S3. The reaction mixture is washed, filtered, and evaporated to dryness to obtain boron trifluoride-diethyl ether complex.

2. The method for preparing the complex according to claim 1, characterized in that, The temperature of the complexation reaction is -20 to 0℃.

3. The method for preparing the complex according to claim 1, characterized in that, In the coordination reaction, the molar ratio of diethyl ether to ketone-boron trifluoride complex is 5-7:

1.

4. The method for preparing the complex according to claim 1, characterized in that, The reaction temperature for the coordination reaction is -10 to 0℃.

5. The method for preparing the complex according to claim 1, characterized in that, The ketone intermediates mentioned in S1 are α,β-unsaturated ketones.

6. The method for preparing the complex according to claim 1, characterized in that, The method for preparing boron trifluoride gas includes the following steps: mixing potassium fluoroborate and boron anhydride, adding concentrated sulfuric acid, and heating while stirring to generate boron trifluoride gas.

7. The method for preparing the complex according to claim 6, characterized in that, The heating temperature is 95-120℃.

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