A method for preparing triallyl phosphate

Abstract

The present invention provides a method for preparing triallyl phosphate, belonging to the technical field of battery electrolyte additives. Under the protection of an inert gas, 3-chloropropene, sodium dihydrogen phosphate and a weak base are added to toluene, and the reaction is carried out at room temperature under the action of a catalyst to obtain the triallyl phosphate. The present invention uses 3-chloropropene and sodium dihydrogen phosphate as raw materials. By selecting a suitable weak base and under the condition of the mutual cooperation of a specific solvent and a catalyst, the reaction can be carried out at room temperature, avoiding the increase in production cost caused by low temperature or high temperature, and at the same time effectively improving the yield and purity of triallyl phosphate.

Description

Technical Field

[0001] The present invention relates to the technical field of battery electrolyte additives, and specifically to a preparation method of triallyl phosphate. Background Art

[0002] Triallyl phosphate is a new type of non-aqueous lithium-ion battery electrolyte additive, which helps to form a stable and dense passivation film on the electrode surface, prevent further decomposition of solvent molecules, and can effectively improve the high-temperature storage and high-temperature cycling performance of lithium-ion batteries. At the same time, triallyl phosphate is also an important polymer monomer and can be used as a halogen-free flame retardant in industry.

[0003] The Chinese invention patent with the publication number of 106957332B uses allyl alcohol as a raw material, adds an acid-binding agent to a solvent under nitrogen protection, and then adds phosphorus oxychloride at a temperature below -30°C for reaction to prepare triallyl phosphate. This reaction condition is harsh and not entirely suitable for industrial production.

[0004] The Chinese invention patent application with the publication number of 111825712A reacts phosphate with trichloropropene at a relatively high temperature. After the reaction is completed, the product needs to be rectified, resulting in a high production cost, and side reactions are likely to occur. The post-treatment steps after the reaction are relatively complex and not suitable for industrial production either. Summary of the Invention

[0005] In view of the above problems, the present invention provides a preparation method of triallyl phosphate.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A preparation method of triallyl phosphate, characterized in that, in the protection of an inert gas, 3-chloropropene, sodium dihydrogen phosphate and a weak base are added to toluene, and under the action of a catalyst, the reaction is carried out at room temperature to obtain the triallyl phosphate. The specific chemical reaction formula is as follows:

[0008]

[0009] Further, the weak base is pyridine.

[0010] Further, the molar ratio of sodium dihydrogen phosphate to the weak base is 1:2.05 - 2.1.

[0011] Further, the molar ratio of 3-chloropropene to sodium dihydrogen phosphate is 3.1 - 3.2:1.

[0012] Further, the catalyst is benzyltriethylammonium chloride.

[0013] Further, the weight ratio of sodium dihydrogen phosphate to the catalyst is 1:0.10 - 0.15; the weight-to-volume ratio of sodium dihydrogen phosphate to toluene is 1 g:4 - 6 mL.

[0014] Further, after the reaction is completed, directly filter and concentrate, and add the obtained concentrate to a toluene-chloroform mixed solution for recrystallization to obtain the triallyl phosphate.

[0015] Further, in the toluene-chloroform mixed solution, the volume ratio of toluene to chloroform is 1:2.5 - 3.2.

[0016] Further, the volume ratio of the concentrate to the toluene-chloroform mixed solution is 1:4 - 6.

[0017] Further, during the reaction process, an inert gas needs to be continuously introduced.

[0018] The beneficial effects of the preparation method of the triallyl phosphate of the present invention are as follows:

[0019] The present invention uses 3-chloropropene and sodium dihydrogen phosphate as raw materials. By selecting a suitable weak base and under the condition of the mutual cooperation of a specific solvent and a catalyst, the reaction can be carried out at room temperature, avoiding the increase in production cost caused by low temperature or high temperature, and at the same time effectively improving the yield and purity of triallyl phosphate; the present invention uses 3-chloropropene and sodium dihydrogen phosphate as raw materials, and in the presence of pyridine, pyridine hydrochloride and sodium chloride are produced, which can be directly removed by filtration in the post-treatment stage, and a small amount of hydrogen chloride not neutralized by pyridine will also be removed by concentration, and then recrystallized with a toluene-chloroform mixed solution in a specific ratio, simplifying the post-treatment process; the overall process method of the present invention is simple, easy to operate, the product yield and purity are both high, and the reaction conditions are mild, without harsh production conditions, and it is suitable for industrial production. Specific Embodiments

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Many specific details are set forth in the following description in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0021] Example 1 A Preparation Method of Triallyl Phosphate

[0022] This example is a preparation method of triallyl phosphate, and the specific preparation process includes the following steps carried out in sequence:

[0023] Mix toluene and chloroform with a volume ratio of 1:3 to obtain a toluene-chloroform mixed solution;

[0024] Under nitrogen protection, 24.49 g (0.32 mol) of 3-chloropropene was dissolved in 60 mL of toluene, 1.8 g of benzyltriethylammonium chloride was added, and then 12.00 g (0.1 mol) of sodium dihydrogen phosphate was added in 5 batches (the total time for adding sodium dihydrogen phosphate was 25 min), and 16.22 g (0.205 mol) of pyridine was slowly added dropwise over 30 min. After the addition was complete, the reaction was carried out at room temperature, and nitrogen was bubbled in at a rate of 5 mL / min during the reaction. After the reaction was completed, the nitrogen bubbling was stopped. After filtration and concentration under reduced pressure, the obtained concentrate was recrystallized with 5 times the weight of a toluene-chloroform mixture to obtain 21.69 g of triallyl phosphate, with a yield of 99.41% and a purity of 99.95%. The specific chemical reaction formula is as follows:

[0025]

[0026] Example 2 A method for preparing triallyl phosphate

[0027] This example is a method for preparing triallyl phosphate. The specific preparation process includes the following steps carried out in sequence:

[0028] Mix toluene and chloroform in a volume ratio of 1:3.2 to obtain a toluene-chloroform mixture;

[0029] Under nitrogen protection, 23.72 g (0.31 mol) of 3-chloropropene was dissolved in 48 mL of toluene, 1.6 g of benzyltriethylammonium chloride was added, and then 12.00 g (0.1 mol) of sodium dihydrogen phosphate was added in 5 batches (the total time for adding sodium dihydrogen phosphate was 30 min), and 16.61 g (0.21 mol) of pyridine was slowly added dropwise over 40 min. After the addition was complete, the reaction was carried out at room temperature, and nitrogen was bubbled in at a rate of 8 mL / min during the reaction. After the reaction was completed, the nitrogen bubbling was stopped. After filtration and concentration under reduced pressure, the obtained concentrate was recrystallized with 4 times the weight of the toluene-chloroform mixture to obtain 21.65 g of triallyl phosphate, with a yield of 99.23% and a purity of 99.97%.

[0030] Example 3 A method for preparing triallyl phosphate

[0031] This example is a method for preparing triallyl phosphate. The specific preparation process includes the following steps carried out in sequence:

[0032] Mix toluene and chloroform in a volume ratio of 1:2.8 to obtain a toluene-chloroform mixture;

[0033] Under nitrogen protection, 24.10 g (0.315 mol) of 3-chloropropene was dissolved in 72 mL of toluene, 1.2 g of benzyltriethylammonium chloride was added, then 12.00 g (0.1 mol) of sodium dihydrogen phosphate was added in 5 batches (the total time for adding sodium dihydrogen phosphate was 35 min), and 14.45 g (0.208 mol) of pyridine was slowly added dropwise over 40 min. After the addition of pyridine was complete, the reaction was carried out at room temperature, and nitrogen was bubbled in at a rate of 3 mL / min during the reaction. After the reaction was completed, the bubbling of nitrogen was stopped. After filtration and concentration under reduced pressure, the resulting concentrate was recrystallized with 5.5 times the weight of a toluene-chloroform mixture to obtain 21.66 g of triallyl phosphate, with a yield of 99.27% and a purity of 99.94%.

[0034] Example 4 A method for preparing triallyl phosphate

[0035] This example is a method for preparing triallyl phosphate. The specific preparation process includes the following steps carried out in sequence:

[0036] Mix toluene and chloroform in a volume ratio of 1:2.5 to obtain a toluene-chloroform mixture;

[0037] Under nitrogen protection, 24.26 g (0.317 mol) of 3-chloropropene was dissolved in 55 mL of toluene, 1.5 g of benzyltriethylammonium chloride was added, then 12.00 g (0.1 mol) of sodium dihydrogen phosphate was added in 5 batches (the total time for adding sodium dihydrogen phosphate was 25 min), and 16.22 g (0.205 mol) of pyridine was slowly added dropwise over 35 min. After the addition of pyridine was complete, the reaction was carried out at room temperature, and nitrogen was bubbled in at a rate of 6 mL / min during the reaction. After the reaction was completed, the bubbling of nitrogen was stopped. After filtration and concentration under reduced pressure, the resulting concentrate was recrystallized with 6 times the weight of the toluene-chloroform mixture to obtain 21.68 g of triallyl phosphate, with a yield of 99.36% and a purity of 99.97%.

[0038] Example 5 A method for preparing triallyl phosphate

[0039] This example is a method for preparing triallyl phosphate. The specific preparation process includes the following steps carried out in sequence:

[0040] Mix toluene and chloroform in a volume ratio of 1:2.6 to obtain a toluene-chloroform mixture;

[0041] Under nitrogen protection, 24.03 g (0.314 mol) of 3-chloropropene was dissolved in 65 mL of toluene, 1.7 g of benzyltriethylammonium chloride was added, and then 12.00 g (0.1 mol) of sodium dihydrogen phosphate was added in 5 batches (the total time for adding sodium dihydrogen phosphate was 30 min), and 16.37 g (0.207 mol) of pyridine was slowly added dropwise over 35 min. After the addition of pyridine was complete, the reaction was carried out at room temperature, and nitrogen was bubbled in at a rate of 7 mL / min during the reaction. After the reaction was completed, the bubbling of nitrogen was stopped. After filtration and concentration under reduced pressure, the concentrated product was recrystallized with 4.5 times the weight of a toluene-chloroform mixture to obtain 21.66 g of triallyl phosphate, with a yield of 99.27% and a purity of 99.96%.

[0042] Comparative Example 1

[0043] Commercially available finished products of triallyl phosphate were purchased, and 5 sets of finished products were randomly selected and their purities were determined using a high-performance gas chromatograph. The average purity was 96.4%.

[0044] The purities of the finished products in Examples 1 to 6 were compared with the product yields and purities in Comparative Example 1, and the comparison results are shown in Table 1.

[0045] Table 1

[0046] Project Yield (%) Purity (%) Example 1 99.41 99.95 Example 2 99.23 99.97 Example 3 99.27 99.94 Example 4 99.36 99.97 Example 5 99.27 99.96 Comparative Example 1 / 96.4

[0047] Application experiment:

[0048] Using ternary material NCM(622) lithium as the positive electrode material, mesophase carbon microspheres as the negative electrode, aluminum foil and copper foil as the positive and negative current collectors respectively, and a ceramic separator to form a soft-pack battery. After injecting the electrolyte, the soft-pack battery was assembled in a glove box and left standing for 8 hours before testing. At a constant temperature of 25 °C at room temperature, the battery was activated by charging and discharging at 1 / 10C from 3.0 V to above 4.2 V to obtain the battery to be tested. The electrolytes to be tested included basic electrolyte E1 and electrolyte E2, and their compositions are as follows:

[0049] 1. Basic electrolyte E1

[0050] EC:Solution-1:DEC = 3:3:4 (v:v:v), LiPF6: 1.0 M, 0.5% LiFSI, 1% VC

[0051] 2. Electrolyte E2

[0052] EC:Solution-1:DEC = 3:3:4 (v:v:v), LiPF6: 1.0 M, 0.5% LiFSI, 1% VC, 1% triallyl phosphate additive

[0053] Test results:

[0054] 1. The test results after cycling at 60°C are as follows:

[0055] Table 2

[0056]

[0057] 2. Place the battery in a low-temperature chamber and control the temperature at -30°C or -40°C respectively for 240 minutes, and then measure the capacity retention rate of the battery.

[0058] Table 3

[0059]

[0060] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing triallyl phosphate, characterized in that, The preparation method is as follows: under the protection of an inert gas, 3-chloropropene, sodium dihydrogen phosphate and a weak base are added to toluene, and the reaction is carried out at room temperature under the action of a catalyst to obtain the triallyl phosphate. The specific chemical reaction formula is as follows: The weak base is pyridine; the molar ratio of sodium dihydrogen phosphate to the weak base is 1:2.05 - 2.1; the catalyst is benzyltriethylammonium chloride.

2. The preparation method of triallyl phosphate according to claim 1, characterized in that, The molar ratio of 3-chloropropene to sodium dihydrogen phosphate is 3.1 - 3.2:

1.

3. The preparation method of triallyl phosphate according to claim 1, characterized in that, The weight ratio of sodium dihydrogen phosphate to the catalyst is 1:0.10 - 0.15; the weight-volume ratio of sodium dihydrogen phosphate to toluene is 1 g:4 - 6 mL.

4. The preparation method of triallyl phosphate according to claim 1, characterized in that, After the reaction is completed, it is directly filtered and concentrated. The obtained concentrate is recrystallized with a toluene-chloroform mixed solution to obtain the triallyl phosphate.

5. The preparation method of triallyl phosphate according to claim 4, characterized in that, In the toluene-chloroform mixed solution, the volume ratio of toluene to chloroform is 1:2.5 - 3.

2.

6. The preparation method of triallyl phosphate according to claim 4, characterized in that, The volume ratio of the concentrate to the toluene-chloroform mixed solution is 1:4 - 6.

7. The preparation method of triallyl phosphate according to claim 1, 5 or 6, characterized in that, During the reaction process, an inert gas needs to be continuously bubbled in.

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