Method for purifying vinylene carbonate

Abstract

The invention relates to a purifying method of vinylene carbonate, which comprises mixing curde vinylene carbonate and solvent, cooling and crystallizing the mixture, and separating solid product, wherein the mixing, cooling and crystallizing processes are processed under the protection of inertia gas. The invention can obtain vinylene carbonate at high purity and reach recover rate more than 98%, with uniform grains, reduced crystallization time and improved production efficiency.

Description

technical field

[0001] The invention relates to a method for purifying vinylene carbonate. Background technique

[0002] With the continuous expansion of the use of lithium-ion batteries, the technology of lithium-ion batteries is also improving. Adding some additives to the electrolyte as the "blood" of lithium-ion batteries can improve many performances of the battery. Among them, vinylene carbonate is an organic film-forming additive and overcharge protection additive in the electrolyte, which has good high and low temperature performance and anti-flat function, can increase the stability of the solvent, effectively inhibit the decomposition of the solvent, and promote The formation of the SEI film improves the cycle performance of the battery. However, due to the heat sensitivity of vinylene carbonate itself and the chlorination-dechlorination route usually used in the synthesis of vinylene carbonate, it is difficult to achieve high purity and high chlorine content of v...

Examples

Embodiment 1

[0029]First, the 250-liter crystallizer is replaced with nitrogen, then 40 kg of toluene as an aromatic hydrocarbon solvent and 40 kg of n-hexane as an aliphatic hydrocarbon solvent are added to the crystallizer, and 40 kg of crude carbonic acid with a purity of 91% and a chlorine content of 3540 ppm Add vinylene ester to the above solvent, mix at 14°C, stir for 7 hours to fully dissolve the crude vinylene carbonate in the solvent, start the water bath cooling device, slowly cool down to 4°C at a rate of 2°C / hour, and stir After 4 hours, vinylene carbonate crystallized out of the solvent. Then the mixture of vinylene carbonate crystallization and solvent is centrifuged, the obtained crystals are added to 2°C n-hexane, stirred and washed, centrifuged, and the washed crystals are vacuum freeze-dried at -5°C, and the final purity is 35.94 kg of 99.97% vinylene carbonate, after testing, the chlorine content is 134ppm, the recovery rate is 98.7%. (purity analyzed by gas chromatogr...

Embodiment 2

[0033] First, replace the 250-liter crystallizer with nitrogen, then add 80 kg of toluene as an aromatic hydrocarbon solvent into the crystallizer, the mixing temperature is 16 ° C, and add 40 kg of crude vinylene carbonate with a purity of 92% and a chlorine content of 2110 ppm In the above solvent, start ultrasonic oscillation for 30 minutes at a frequency of 100 kHz to fully dissolve the crude vinylene carbonate in the solvent, start the water bath cooling device, and slowly cool down to 2°C at a rate of 6°C / hour and keep it for 1 hour , vinylene carbonate crystallized from the solvent. Then the mixture of vinylene carbonate crystallization and solvent is centrifuged, and the obtained crystals are added to 0°C n-hexane, stirred and washed, centrifuged, and the washed crystals are vacuum freeze-dried at -10°C, and the final purity is 36.4 kg of 99.97% vinylene carbonate, after testing, the chlorine content is 102ppm, the recovery rate is 99%. (purity analyzed by gas chromat...

Embodiment 3

[0035] First the crystallizer of 250 liters is replaced with nitrogen, then 200 kilograms of toluene as aromatic hydrocarbon solvent, 100 kilograms of ethanol as polar solvent and 100 kilograms of n-hexane as aliphatic hydrocarbon solvent are added in the crystallizer, and the water bath cooling device is started. 40 kg of crude vinylene carbonate with a purity of 90.5%, a chlorine content of 3120 ppm, and melting at 35° C. was added to the above solvent, the mixing temperature was 20° C., and ultrasonic oscillation was started for 1.5 hours at a frequency of 85 kHz. Slowly cool down to 6°C at a rate of 3°C / hour and hold for 1 hour. Then the mixture was centrifuged, and the obtained crystals were added to n-hexane at 4°C, stirred and washed, centrifuged, and the crystals were vacuum freeze-dried at 0°C, and finally 35.67 kg of vinylene carbonate with a purity of 99.95% was obtained. , the chlorine content is 123ppm, and the recovery rate is 98.5%. (purity analyzed by gas chro...

technical field

[0001] The invention relates to a method for purifying vinylene carbonate. Background technique

[0002] With the continuous expansion of the use of lithium-ion batteries, the technology of lithium-ion batteries is also improving. Adding some additives to the electrolyte as the "blood" of lithium-ion batteries can improve many performances of the battery. Among them, vinylene carbonate is an organic film-forming additive and overcharge protection additive in the electrolyte, which has good high and low temperature performance and anti-flat function, can increase the stability of the solvent, effectively inhibit the decomposition of the solvent, and promote The formation of the SEI film improves the cycle performance of the battery. However, due to the heat sensitivity of vinylene carbonate itself and the chlorination-dechlorination route usually used in the synthesis of vinylene carbonate, it is difficult to achieve high purity and high chlorine content of v...

Examples

Embodiment 1

[0029]First, the 250-liter crystallizer is replaced with nitrogen, then 40 kg of toluene as an aromatic hydrocarbon solvent and 40 kg of n-hexane as an aliphatic hydrocarbon solvent are added to the crystallizer, and 40 kg of crude carbonic acid with a purity of 91% and a chlorine content of 3540 ppm Add vinylene ester to the above solvent, mix at 14°C, stir for 7 hours to fully dissolve the crude vinylene carbonate in the solvent, start the water bath cooling device, slowly cool down to 4°C at a rate of 2°C / hour, and stir After 4 hours, vinylene carbonate crystallized out of the solvent. Then the mixture of vinylene carbonate crystallization and solvent is centrifuged, the obtained crystals are added to 2°C n-hexane, stirred and washed, centrifuged, and the washed crystals are vacuum freeze-dried at -5°C, and the final purity is 35.94 kg of 99.97% vinylene carbonate, after testing, the chlorine content is 134ppm, the recovery rate is 98.7%. (purity analyzed by gas chromatogr...

Embodiment 2

[0033] First, replace the 250-liter crystallizer with nitrogen, then add 80 kg of toluene as an aromatic hydrocarbon solvent into the crystallizer, the mixing temperature is 16 ° C, and add 40 kg of crude vinylene carbonate with a purity of 92% and a chlorine content of 2110 ppm In the above solvent, start ultrasonic oscillation for 30 minutes at a frequency of 100 kHz to fully dissolve the crude vinylene carbonate in the solvent, start the water bath cooling device, and slowly cool down to 2°C at a rate of 6°C / hour and keep it for 1 hour , vinylene carbonate crystallized from the solvent. Then the mixture of vinylene carbonate crystallization and solvent is centrifuged, and the obtained crystals are added to 0°C n-hexane, stirred and washed, centrifuged, and the washed crystals are vacuum freeze-dried at -10°C, and the final purity is 36.4 kg of 99.97% vinylene carbonate, after testing, the chlorine content is 102ppm, the recovery rate is 99%. (purity analyzed by gas chromat...

Embodiment 3

[0035] First the crystallizer of 250 liters is replaced with nitrogen, then 200 kilograms of toluene as aromatic hydrocarbon solvent, 100 kilograms of ethanol as polar solvent and 100 kilograms of n-hexane as aliphatic hydrocarbon solvent are added in the crystallizer, and the water bath cooling device is started. 40 kg of crude vinylene carbonate with a purity of 90.5%, a chlorine content of 3120 ppm, and melting at 35° C. was added to the above solvent, the mixing temperature was 20° C., and ultrasonic oscillation was started for 1.5 hours at a frequency of 85 kHz. Slowly cool down to 6°C at a rate of 3°C / hour and hold for 1 hour. Then the mixture was centrifuged, and the obtained crystals were added to n-hexane at 4°C, stirred and washed, centrifuged, and the crystals were vacuum freeze-dried at 0°C, and finally 35.67 kg of vinylene carbonate with a purity of 99.95% was obtained. , the chlorine content is 123ppm, and the recovery rate is 98.5%. (purity analyzed by gas chro...