WO2020224268A1

WO2020224268A1 - Synthesis method for 4,4'-bi-1,3-dioxolane-2,2'-dione

Info

Publication number: WO2020224268A1
Application number: PCT/CN2019/127304
Authority: WO
Inventors: 闫彩桥; 葛建民; 王军; 郝俊; 张民; 武利斌; 侯荣雪
Original assignee: 石家庄圣泰化工有限公司
Priority date: 2019-05-05
Filing date: 2019-12-23
Publication date: 2020-11-12
Also published as: CN111892569A; JP7315810B2; KR102509669B1; JP2022530931A; KR20210044829A

Abstract

A synthesis method for 4,4'-bi-1,3-dioxolane-2,2'-dione, relating to the technical field of battery electrolyte additives, and comprising: adding an imidazole and tetrahydrofuran to a reactor in an argon atmosphere, cooling same to -5 to 5ºC, starting dropping phosgene, completing the dropping after 0.5 to 1 h, then dropping the mixture to a tetrahydrofuran solution of erythritol at -8 to -15ºC, completing the dropping after 1 to 1.5 h, maintaining the temperature and stirring same for 0.5 to 2 h, and removing the solvent in vacuum to obtain a residue; dissolving the residue in dichloromethane, washing same by using cold water, drying and then concentrating same to obtain a 4,4'-bi-1,3-dioxolane-2,2'-dione crude product, and purifying the crude product to obtain refined 4,4'-bi-1,3-dioxolane-2,2'-dione. According to the present invention, the raw materials used are easy to obtain, and the synthesis method is simple to operate, low in energy consumption, short in reaction time, mild and stable in reaction conditions, and high in product yield, which is up to 94%.

Description

Synthesis method of 4,4'-linked-1,3-dioxolane-2,2'-dione

Technical field

The present invention belongs to the technical field of battery electrolyte additives, and relates to the use of 4,4'-dioxolane-2,2'-dione as a battery electrolyte additive, and specifically relates to 4,4'- Synthetic method of bi-1,3-dioxolane-2,2'-dione.

Background technique

The continuous improvement of lithium-ion battery performance has made it more and more widely used, but its safety issues and cycle performance have restricted the development of lithium-ion batteries to a certain extent. In particular, the current relatively hot power lithium-ion batteries for electric vehicles, safety performance, fast charging performance, and endurance are hot issues studied by various research institutions. The key to solving these problems should start from the battery itself. There are many factors that affect the safety and cycle stability of lithium-ion batteries, which can be divided into internal and external factors. The internal cause mainly involves the stability of the positive and negative active materials, the characteristics of the electrolyte itself and its compatibility with electrode materials, and the stability of the separator material. The external cause is mainly the incorrect use of the battery and the abuse during use. Through research, it is found that the introduction of electrolyte additives is a very effective method, which can not only improve the characteristics of the electrolyte itself, but also improve the compatibility of the electrolyte and the electrode material, and adding a small amount will have a significant effect . The modification of the electrode material can further improve the cycle stability of the lithium ion battery.

In recent years, many new multifunctional lithium ion battery electrolyte additives have appeared. However, our research found that 4,4'-linked-1,3-dioxolane-2,2'-dione with CAS number 24690-44-6 can effectively improve lithium ion batteries as an electrolyte additive The structural stability and thermal stability of the positive and negative electrode materials. In addition, 4,4'-linked-1,3-dioxolane-2,2'-dione exhibits excellent cycling and safety performance under high voltage, extremely high and low temperature conditions, which is useful for improving the performance of lithium-ion batteries. Great promotion. However, the existing 4,4'-linked-1,3-dioxolane-2,2'-dione synthesis process is still immature, and the synthesis process usually involves expensive raw materials, complex processes, product yield and purity Low-level problems, and currently in the synthesis process of 4,4'-linked-1,3-dioxolane-2,2'-dione, it is generally believed that high temperature should be used for the reaction, such as 60-130°C, etc. The time is more than 12 hours, although the yield can reach about 88-90%, but the reaction temperature is high, the reaction is unstable, and the reaction time is too long, which affects the production efficiency. Therefore, it is of great practical significance to study the synthesis method of 4,4'-linked-1,3-dioxolane-2,2'-dione.

Summary of the invention

In order to solve the above technical problems, the present invention provides a method for synthesizing 4,4'-bi-1,3-dioxolane-2,2'-dione. The synthesis method of the present invention is simple, and the raw materials are cheap and easily available. The energy consumption is low, the reaction conditions are mild and stable, and the yield is high.

The technical scheme adopted by the present invention to achieve its purpose is:

The synthesis method of 4,4'-linked-1,3-dioxolane-2,2'-dione, adding imidazole and tetrahydrofuran into the reactor under argon atmosphere, cooling down to -5～5℃ , Start to add phosgene dropwise, 0.5-1h to finish, stir for 0.5-1h, filter to obtain the filtrate containing 1,1'-carbonyldiimidazole; then at -8～-15℃, the filtrate is added dropwise to In the tetrahydrofuran solution of butanetetraol, the dripping is completed for 1-1.5h, the temperature is kept and stirred for 0.5-2h, and the solvent is removed in vacuo to obtain a residue; the residue is dissolved in dichloromethane, washed with cold water, dried and concentrated to obtain 4, 4'-Bi-1,3-dioxolane-2,2'-dione crude product, the crude product is purified to obtain refined 4,4'-dioxolane-2,2' -Diketone.

The molar ratio of phosgene, imidazole and butanetetraol is 1: (3-6): (0.45-0.8).

Tetrahydrofuran solution of butanetetraol (1g/4-4.5ml). That is, 4-4.5ml tetrahydrofuran solution contains 1g tetrahydrofuran.

Wash 2-3 times in cold water.

Dry using anhydrous sodium sulfate and/or calcium oxide.

The concentration control vacuum is 0.08-0.10MPa, and the concentration is 1.5-2h at a temperature of 50-60℃.

Purification uses acetone for recrystallization.

The vacuum degree of the solvent is controlled to 0.08-0.09Mpa, and the vacuum treatment time is 30-40min.

The beneficial effects of the present invention are:

The raw materials used in the invention are cheap and easily available, the synthesis method is simple and easy to operate, low energy consumption, short reaction time, mild and stable reaction conditions, and high product yield, which can reach more than 94%.

This application uses low-temperature reaction, breaking the current situation that is generally believed to require high-temperature reaction, and opens up a new method for synthesizing 4,4'-bi-1,3-dioxolane-2,2'-dione . Those skilled in the art generally believe that in the preparation of 4,4'-bi-1,3-dioxolane-2,2'-dione, high temperature and long time reaction will promote the progress of the reaction, which is beneficial to 4,4' -Synthesis of 1,3-dioxolane-2,2'-dione; if the temperature is low, it will affect the progress of the reaction, slow down the reaction speed, and the yield will be low, even resulting in failure to synthesize 4,4'-dione -1,3-dioxolane-2,2'-dione. After long-term research, the inventors used phosgene, imidazole, and butanetetraol as raw materials to prepare 4,4'-bi-1,3-dioxolane-2,2'-dione, which can achieve low temperature and short time The reaction is synthesized, and the yield reaches more than 94%.

Description of the drawings

Figure 1 is the cycle performance diagram of the LP063450AR square lithium-ion battery with a rated capacity of 950mAh.

Fig. 2 is a graph showing the cycle performance of a LP063450AR prismatic lithium ion battery with a rated capacity of 950 mAh added with 4,4'-linked-1,3-dioxolane-2,2'-dione of the present invention.

Figure 3 is a mass spectrum of 4,4'-bi-1,3-dioxolane-2,2'-dione prepared by the present invention.

Fig. 4 is a partial cut-out view of Fig. 3.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments.

One, specific embodiment

Example 1

Under argon atmosphere, add 4.0mol imidazole and 125ml tetrahydrofuran into a four-necked flask, cool down to 0℃, start dripping 1.0mol phosgene, drip for 0.5h, stir for 0.5h, and filter to obtain 1,1' -The filtrate of carbonyl diimidazole. Afterwards, at a temperature of -10°C, the filtrate was added dropwise to a solution of 0.5 mol tetrahydrofuran (250 ml) of tetrahydrofuran (250 ml), and the dropping was completed in 1.5 hours. After stirring for 1 hour, the solvent was removed in vacuo to obtain a residue. The residue was dissolved in dichloromethane and washed twice with cold water. Add 20g of anhydrous sodium sulfate to dry and concentrate to obtain crude 4,4'-bi-1,3-dioxolane-2,2'-dione. The crude product was recrystallized to obtain 82.20 g of pure 4,4'-dioxolane-2,2'-dione (yield 94.4%).

The obtained 4,4'-bi-1,3-dioxolane-2,2'-dione was collected, the density was determined to be 1.6075g/cm ³ , the boiling point was 535.33°C (760mmHg), and the purity was 99.87 by HPLC %.

Example 2

Under argon atmosphere, 3.0mol imidazole and 62ml tetrahydrofuran were added to the four-necked flask, cooled to -2°C, and 1.0mol phosgene was added dropwise. After 0.6h, the mixture was stirred for 0.6h and filtered to obtain the content of 1,1 '-Carbonyl diimidazole filtrate. Then, at -8°C, the filtrate was added dropwise to a tetrahydrofuran (220 ml) solution containing 0.45 mol of tetrahydrofuran (220 ml) for 1 hour, the mixture was kept warm and stirred for 1.5 hours, and the solvent was removed in vacuo to obtain a residue. The residue was dissolved in dichloromethane and washed twice with cold water. Add 20g of anhydrous sodium sulfate to dry and concentrate to obtain crude 4,4'-bi-1,3-dioxolane-2,2'-dione. The crude product was recrystallized to obtain 74.4 g of pure 4,4'-dioxolane-2,2'-dione (yield 94.96%).

The obtained 4,4'-bi-1,3-dioxolane-2,2'-dione was collected, and the measured density was 1.6083g/cm ³ , the boiling point was 535.38°C (760mmHg), and the purity was 99.89 by HPLC. %.

Example 3

Add 5.0 mol imidazole and 204 ml tetrahydrofuran to a four-necked flask under argon atmosphere, cool down to -5°C, start to add 1.0 mol phosgene dropwise, drop for 0.8h, stir for 0.8h, and filter to obtain a content of 1,1 '-Carbonyl diimidazole filtrate. Then, at -12°C, the filtrate was added dropwise to a tetrahydrofuran (384 ml) solution containing 0.7 mol of butane erythritol for 1.2 hours, and the mixture was kept and stirred for 0.8 hours, and the solvent was removed in vacuo to obtain a residue. The residue was dissolved in dichloromethane and washed twice with cold water. Add 20g of anhydrous sodium sulfate to dry and concentrate to obtain crude 4,4'-bi-1,3-dioxolane-2,2'-dione. The crude product was recrystallized to obtain 82.95 g 4,4'-dioxolane-2,2'-dione pure product (yield 95.29%).

The obtained 4,4'-linked-1,3-dioxolane-2,2'-dione was collected and the density was determined to be 1.6078g/cm ³ , the boiling point was 535.47°C (760mmHg), and the purity was 99.91 by HPLC %.

Example 4

Add 6.0mol imidazole and 164ml tetrahydrofuran into a four-neck flask under argon atmosphere, cool down to 5℃, start to add 1.0mol phosgene dropwise, drop for 1h, stir for 1h, filter, and obtain 1,1'-carbonyl group The filtrate of diimidazole. Then, at a temperature of -15°C, the filtrate was added dropwise to a solution of 0.6 mol tetrahydrofuran (307 ml) of tetrahydrofuran (307 ml), and the drop was completed in 1.5 hours. After stirring for 2 hours, the solvent was removed in vacuo to obtain a residue. The residue was dissolved in dichloromethane and washed twice with cold water. Add 20g of anhydrous sodium sulfate to dry and concentrate to obtain crude 4,4'-bi-1,3-dioxolane-2,2'-dione. The crude product was recrystallized to obtain 83.4 g of pure 4,4'-dioxolane-2,2'-dione (yield 95.8%).

The obtained 4,4'-linked-1,3-dioxolane-2,2'-dione was collected, and the measured density was 1.609g/cm ³ , the boiling point was 535.71°C (760mmHg), and the purity was 99.85 by HPLC. %.

Example 5

Under argon atmosphere, 4.0mol imidazole and 136ml tetrahydrofuran were added to a four-necked flask, cooled to 3°C, and 1.0 mol phosgene was added dropwise. After 0.7h, the mixture was stirred for 0.7h and filtered to obtain 1,1' -The filtrate of carbonyl diimidazole. Then, at -13°C, the filtrate was added dropwise to a solution of 0.8 mol tetrahydrofuran (420 ml) of tetrahydrofuran (420 ml) for 1.3 hours, the mixture was kept and stirred for 0.5 hours, and the solvent was removed in vacuo to obtain a residue. The residue was dissolved in dichloromethane and washed twice with cold water. Add 20g of anhydrous sodium sulfate to dry and concentrate to obtain crude 4,4'-bi-1,3-dioxolane-2,2'-dione. The crude product was recrystallized to obtain 83.74 g of pure 4,4'-dioxolane-2,2'-dione (yield 96.2%).

The obtained 4,4'-bi-1,3-dioxolane-2,2'-dione was collected, and the density was determined to be 1.6087g/cm ³ , the boiling point was 535.64°C (760mmHg), and the purity was 99.86 by HPLC. %.

Example 6

Under argon atmosphere, 4.0mol imidazole and 125ml tetrahydrofuran were added to a four-necked flask, cooled to -3°C, and 1.0 mol phosgene was added dropwise. After 0.9h, the mixture was stirred for 0.9h and filtered to obtain 1,1 '-Carbonyl diimidazole filtrate. Afterwards, at -9°C, the filtrate was added dropwise to a solution of 0.5 mol tetrahydrofuran (268 ml) of tetrahydrofuran (268 ml) for 1.4 hours, kept and stirred for 1.8 hours, and the solvent was removed in vacuo to obtain a residue. The residue was dissolved in dichloromethane and washed twice with cold water. Add 20g of anhydrous sodium sulfate to dry and concentrate to obtain crude 4,4'-bi-1,3-dioxolane-2,2'-dione. The crude product was recrystallized to obtain 84 g of pure 4,4'-dioxolane-2,2'-dione (yield 96.5%).

The obtained 4,4'-bi-1,3-dioxolane-2,2'-dione was collected, and the measured density was 1.6073g/cm ³ , the boiling point was 535.38°C (760mmHg), and the purity was 99.86 by HPLC. %.

Example 7

Under argon atmosphere, 4.0mol imidazole and 125ml tetrahydrofuran were added to the four-necked flask, cooled to -1°C, and 1.0mol phosgene was added dropwise. After 0.6h, the mixture was stirred for 0.6h and filtered to obtain 1,1 '-Carbonyl diimidazole filtrate. Afterwards, at a temperature of -11°C, the filtrate was added dropwise to a tetrahydrofuran (240 ml) solution containing 0.45 mol of tetrahydrofuran (240 ml) for 1.2 hours, kept and stirred for 1.2 hours, and the solvent was removed in vacuo to obtain a residue. The residue was dissolved in dichloromethane and washed twice with cold water. Add 20 g of anhydrous sodium sulfate, dry, and concentrate to obtain crude 4,4'-dioxolane-2,2'-dione. The crude product was recrystallized to obtain 76.23 g 4,4'-dioxolane-2,2'-dione pure product (yield 97.3%).

The obtained 4,4'-linked-1,3-dioxolane-2,2'-dione was collected and subjected to mass spectrometric detection. The mass spectra of the detection are shown in Figure 3 and Figure 4, and the measured density is 1.6088g/cm ³ . The boiling point is 535.68°C (760mmHg), and the purity is 99.84% by HPLC.

2. Test performance

1. High temperature performance research

The lithium-ion battery used in the experimental study is the LP063450AR square lithium-ion battery with a rated capacity of 950mAh produced by BYD Co., Ltd. The battery is subjected to 1c rate (950mA) charge-discharge cycle test at 25℃ and 5℃ respectively, using constant current and constant voltage charging system (CC-CV) and constant current discharge system, the charging and discharging voltage range is 3.0-4.5V, first Charge with 1C constant current to 4.5V, then charge with 4.5V constant voltage until the current is less than 20mA, and then discharge with 1C constant current until the final voltage is 3.0V, so the cycle of charge and discharge is 500 times. The cycle data is collected in LAND-2001T Performed on the battery test system.

Referring to Figure 1, after 300 cycles, the capacity retention rate of the battery cycled at 25°C is 88.8%, while the capacity of the battery at 65°C is only 73.1%, and the capacity decays rapidly. This shows the rated capacity produced by BYD Co., Ltd. The cycle stability of the 950mAh LP063450AR prismatic lithium-ion battery at 65°C is worse than that at 25°C. It is also found from Figure 1 that the discharge capacity of the battery at 65°C is higher than the rated capacity of the battery. The reason is that the viscosity of the electrolyte decreases at high temperatures, which accelerates the migration rate of lithium ions and increases the utilization rate of active lithium. As a result, lithium batteries exhibit higher charge and discharge capacity.

In order to verify that the 4,4'-linked-1,3-dioxolane-2,2'-dione prepared by the present invention has the function of improving the high temperature performance of the battery, we used the rated capacity produced by BYD Co., Ltd. to be 950mAh The LP063450AR square lithium-ion battery is the test object. Add 2% of the electrolyte mass of 4,4'-dioxolane-2,2'-dione to the electrolyte of the battery, repeat Perform the same operation as above to test the high temperature cycle performance of the battery.

Referring to Figure 2, after 300 cycles, the battery with the addition of 4,4'-link-1,3-dioxolane-2,2'-dione of the present invention has a battery capacity of 87.6% at 65°C, 500 cycles The battery capacity at 65°C after cycling is 75.2%, but the battery without adding the 4,4'-link-1,3-dioxolane-2,2'-dione of the present invention is the battery at 65°C after 500 cycles The capacity is 59%, end of life. It can be seen that the 4,4'-linked-1,3-dioxolane-2,2'-dione prepared by the present invention can improve the cycle performance of the battery under high voltage and high temperature.

2. Low temperature performance research

Taking LiFePO ₄ lithium-ion battery as the research object, the size is 12.cm*7cm*0.8cm, the rated capacity of a single battery is 10Ah, the working voltage is 3.3-4.2V, and the outer shell is aluminum-plastic film, and the low temperature test is carried out. Take 25℃ as the low temperature test reference point, starting from 25℃ to -20℃, every 5℃ is a temperature inspection point, the temperature change rate is 30min/5℃, and the temperature can be carried out after being left for 24h at each temperature point. The performance test, the test results are shown in Table 1.

Table 1 The influence of temperature on discharge capacity (0.5C)

From Table 1 above, it can be seen that the lower the temperature, the more serious the capacity attenuation, indicating that the subject of this experiment has the problem of poor low-temperature cycle performance.

In order to verify that the 4,4'-linked-1,3-dioxolane-2,2'-dione prepared by the present invention has the function of improving the low temperature performance of the battery, we used the same LiFePO ₄ lithium ion battery as the research Subject: Add 2% of the electrolyte mass of 4,4'-dioxolane-2,2'-dione to the electrolyte of the battery, repeat the same operation as above, and perform the battery low-temperature cycle performance The results are shown in Table 2.

Table 2 The influence of temperature on discharge capacity (0.5C)

It can be seen from Table 2 that the addition of the 4,4'-linked-1,3-dioxolane-2,2'-dione of the present invention can improve the low-temperature cycle performance of the battery.

Claims

The synthesis method of 4,4'-bi-1,3-dioxolane-2,2'-dione is characterized in that imidazole and tetrahydrofuran are added to the reactor under argon atmosphere, and the temperature is cooled down to- 5～5℃, start to add phosgene dropwise, 0.5-1h to finish, stir for 0.5-1h, filter to obtain a filtrate containing 1,1'-carbonyldiimidazole; then at -8～-15℃, the The filtrate was added dropwise to the tetrahydrofuran solution of tetrahydrofuran for 1-1.5h, the temperature was kept and stirred for 0.5-2h, and the solvent was removed in vacuo to obtain a residue; the residue was dissolved in dichloromethane and washed with cold water, after drying Concentrate to obtain crude 4,4'-bi-1,3-dioxolane-2,2'-dione. Purify the crude product to obtain refined 4,4'-bi-1,3-dioxolane- 2,2'-Diketone.
The method for synthesizing 4,4'-linked-1,3-dioxolane-2,2'-dione according to claim 1, wherein the molar ratio of phosgene, imidazole and butanetetraol is 1: (3-6): (0.45-0.8).
The method for synthesizing 4,4'-linked-1,3-dioxolane-2,2'-dione according to claim 1, wherein the tetrahydrofuran solution of butanetetraol (1g/4-4.5 ml).
The method for synthesizing 4,4'-linked-1,3-dioxolane-2,2'-dione according to claim 1, characterized in that it is washed 2-3 times in cold water.
The method for synthesizing 4,4'-linked-1,3-dioxolane-2,2'-dione according to claim 1, characterized in that the drying uses anhydrous sodium sulfate and/or calcium oxide drying .
The method for synthesizing 4,4'-linked-1,3-dioxolane-2,2'-dione according to claim 1, wherein the concentration control vacuum degree is 0.08-0.10MPa, and the temperature Concentrate at 50-60°C for 1.5-2h.
The method for synthesizing 4,4'-linked-1,3-dioxolane-2,2'-dione according to claim 1, characterized in that acetone is used for recrystallization for purification.
The method for synthesizing 4,4'-linked-1,3-dioxolane-2,2'-dione according to claim 1, characterized in that the degree of vacuum for removing the solvent in vacuum is controlled to be 0.08-0.09Mpa , The vacuum treatment time is 30-40min.